Web Server

Web Server: A webserver is a Hardware device used to host an eCommerce website. The server supports the entire content of the website such as HTML files, Data bases and Image Files. Web Servers will run on operating systems such as Windows or Linux and will use web server software to manage access requests to the website. Webservers are similar to PC’s however they have faster processors and more memory making it much more powerful.Firewall: A firewall is a software or hardware-based network security system that controls the incoming and outgoing network traffic by analysing the data packets and determining whether they should be allowed through or not, based on a rule set. A firewall establishes a barrier between a trusted, secure internal network and another network (e. g. , the Internet) that is not assumed to be secure and trusted. Software Browsers: When you design an eCommerce solution it is important to consider how the site is seen on the web.When customers access an o nline shop they will need to use a web browser to load the website. A browser is a software application on a machine that allows someone to access the internet. When a website is loaded in a browser the html code, css, image and information that is stored in a database connected to the website are rendered together to make the site appear in the browser window. When developing an eCommerce site it is important to test that the site appears correctly in all of the main browsers that people use to access the internet such as, Internet Explorer, Mozilla Firefox, Google Chrome and Safari.Operating Systems: An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. The operating system is an essential component of the system software in a computer system. Application programs usually require an operating system to function. Web Authoring Tools: web authoring tools are used to develop the front end of a n eCommerce website. A range of software packages can be used .HTML (Hypertext Mark-up Language) files can be created in a web authoring package such as Dreamweaver.The html files created by this software will include CSS (Cascading Style Sheet) files that are used to enhance the visual appearance of the site. Other web authoring tools are graphic design packages such as Adobe Photoshop that can be used to design a skin for the user interface design. This skin can then be exported into a html and css combination that is used as the basis for the developing site. Server Software: Web servers need to run software that manages access attempts to a website.When a user tries to access a website the web server software processes the access request and serves up the correct files that have been requested from the client’s machine. Examples include Windows IIS (internet information services) which runs on windows based web servers and Apache which runs on Linux based web servers. Ser ver Software runs in the background and works over a network to allow a browser stored on a client machine to access the files that make up an eCommerce site. Database System: A database system is an important part of an eCommerce website.The database is used to store information about the products for sale on the site. The database will hold information such as store pricing, descriptions, images and other details. In addition to this the customers details are also stored such as what they ordered, payment details, shipping details, phone numbers, emails and lots more. Staff who are responsible for the delivery of items will use the database that is connected to the eCommerce site to ensure all the correct products are sent to the correct customer.It is important to connect securely to the database to ensure that all orders are processed correctly and the business runs smoothly. Technologies such as a PHP (A programming script) and MySQL are used to communicate between the website and the database management system (DBMS). Network TCP/IP: TCP/IP is a protocol used to transfer data and information over a network such as the internet. TCP (Transfer Control Protocol) is a wired connection between different machines on the internet. A protocol is a rule of how connections are set up between two devices. Anyone using the internet to access an eCommerce website will use TCP/IP.IP stands for Internet Protocol and each device on a network has a fully unique IP address. When a shopper tries to access an eCommerce store they do not need to know the IP address of the web server that the store is hosted on but can type a URL such as www. shop. com into a browser window instead. TCP/IP is a complex technology and normally and eCommerce site developer does not have to have in depth knowledge of the protocols but should understand that they exist. Ports: Ports on different devices allow them to connect to other devices stored on the internet.Ports allow a device with one IP address to access another device with a different unique IP address. A device will normally have more than one port, for example when one user wants to send an email to another they will allow access through port 25 as this is normally reserved for email. When a shopper on a client machine wants to access an eCommerce website they will connect IP addresses from their machine to the web server that stores the eCommerce site over port 80. Other Protocols: FTP (File Transfer Protocol) is the set of rules used to communicate information between two devices running on a TCP/IP based network.If the customer online was to request a receipt this would be sent to them using FTP. Domain Names: When starting an eCommerce site it is important to register a recognisable domain name that links to your company and brand. Successful eCommerce companies on the web have recognisable names such as Amazon, eBay, Nike and Argos that make them stand out from the crowd. These are short one word names tha t are easy to remember and suit the company brand. Programming Requirements: When designing an eCommerce site it is important that everything is programmed correctly.Examples of programming that you might need would be embedding JavaScript in your website to increase functionality. PHP might be used to connect the website to the back end database. Complex search queries to find information about your products would need to run on the back end database based on what the shopper is looking for on your site. Security: There are other programming requirements to consider such as embedding security in your site so that customers' credit and debit card information is secure when they purchase from your store.Download speeds: when running an online business it is important to constantly monitor download speeds of your customers using analytic tools such as Google Analytics. You also need to tailor your website so images are as compressed as possible without compromising the quality of the site. All coding and mark-up must run as efficiently as possible so that the site loads as quickly as possible. Internet connection: Internet access connects individual computer terminals, computers, mobile devices, and computer networks to the Internet, enabling users to access Internet services (for example, email and the World Wide Web).Internet service providers (ISP's) offer Internet access to the public through various technologies that offer a wide range of data signalling rates (speeds). Web Hosting Service: A web hosting service is a type of internet hosting service that allows individuals and organizations such as eCommerce companies to make their website accessible via the World Wide Web. Web hosts are companies that provide space on a server owned or leased for use by clients as well as providing Internet connectivity.

Arduino

ELECTRICAL ENGINEERING TECH. (EE 306) Arduino Research Date: 2013/2/16 INTRODUCTION In this brief report we will discuss a family of electronic boards called Arduino. At the beginning we shall provide an overview of the Arduino boards and what they are. After that we will tackle the board’s component and how the board works. Finally an example of one of the applications will be shown. WHAT IS AN ARDUINO? An Arduino board is simply a microcontroller board. The board is designed with the purpose of facilitating the use of electronics in projects. The use of the board was intentionally made easy so that anyone can use it.The board comes with a software called the Arduino Integrated Development Environment. The software is used to program the Arduino board to do the required operations. An Arduino board receives inputs from different sensors and responds by controlling different types of actuators. It is also worth-mentioning that the board and its software are open-source. It mea ns that anyone can do anything with the board and its software. This nature has made the Arduino boards very popular among users because everyone can innovate with the board and share their innovations.However, this nature has also allowed clones with inferior qualities to be sold under the Arduino name. COMPONENTS There are many types of Arduino boards. Some components vary from type to type, but a simple Arduino board that can be built at home have the following components: 1- An Atmel Microcontroller. 2- LEDs. 3- Resistors. 4- Capacitors. 5- Clock Crystal. 6- Switch 7- Voltage regulator. 8- Connection pins. 9- Diode. 10- Transistors. An Arduino board’s capabilities can be extended by the use of shields. Arduino shields are boards that can be mounted on the Arduino board to perform different tasks.For example the Xbee shield allows multiple Arduino boards to communicate wirelessly, the motor shield allows the Arduino board to control a DC motor. 2|P a ge HOW IT WORKS In gen eral, a code is put in the memory of the board and then processed in the microcontroller. This code interacts with inputs and outputs. Inputs can be signals coming from sensors (light, voice, heat, etc. ) or results from another processed task. After processing the inputs in the microcontroller and applying the codes from the memory, the result comes in an output form (alarm, light, etc. ).Codes are written in the memory by connecting the Arduino board to a computer. Connecting the Arduino board requires the use of an ICSP header or a USB cable such as the one found in the newer versions e. g. Arduino UNO (see figure 1). An Arduino board can be powered from a USB cable, an ACDC adapter or a battery by connecting it in the Gnd and Vin pins. Figure 1: Connect Arduino by USB EXAMPLE OF APPLICATION Blinking LED In this example, we will use the Arduino board like a timer to turn a LED on for 1 second and off for another second. 3|P a ge To do this function see the code below; / Example B linking LED const int LED = 13; void setup () { pinMode(LED, OUTPUT); } void loop() { digitalWrite(LED, HIGH); delay(1000); digitalWrite(LED, LOW); delay(1000); } The First line written after // is a comment that does not affect the program. In the second line, we define the constant attached to pin 13 as LED. After attaching the LED to the pin, we decide whether the LED should be an input or an output, in this case, we chose output. Next, we write the processing code, (digitalWrite(LED, HIGH);) this means to provide voltage to the LED, (delay(1000);) means waiting 1000ms ? s, (digitalWrite(LED, LOW);) means cutting off the voltage, (delay(1000);) the same process, which is waiting 1s. This code will be repeated in a loop. CONCLUSION An Arduino board can be a great starting point for anyone interested in microcontrollers. The board is easy to use and has a wide variety of applications. There are many tutorials available in the world web for the board due to its popularity. Although the board has many advantages, it still has its own limitations. REFERENCE [1] Arduino site, (http://arduino. cc/en/) [2] Simply Arduino, Eng. Abdullah Ali Abdullah, (http://simplyarduino. com/? page_id=5) 4|P a ge

Building Positive Teacher Student Relationships

Teacher-student relationship has numerous benefits for the teacher and the student in the classroom. There are different types of relationships between the teachers and the students. They include that of being a mentor, being friends or a parental figure. However, in the recent decade, a new type of relationship that is unlawful and illegal has developed. When the connection between the student and the teacher starts being that of more than friends, it disadvantages the student. The teacher-student†¦ 2. Student-teacher relationships-To improve my student-teacher relationship the first thing I will do is get to know my students. I need to find out what they like and dislike, and become approachable. This will help me and the student in the long run because we will have some goodwill built with each other, and they may be able to come to me with personal issues that are hindering their learning. The second thing I would do is listen to my students. It is a sort of dictatorship in the classroom†¦ will begin to normalize certain aspects of ideology. â€Å"The social roles that we occupy throughout our lifetime, like child, student, or employee place us in relationships of unequal power and as a result of ideological value hierarchies†(139). This though is considered norm just like a student is supposed to/expected to do their homework. The relationship between teacher and student is a common one. The next function is privileging basically states that people of power are more important than others.†¦ collaborate with colleagues. Collaboration between colleagues build relationships among teachers and plays a significant role in the growth of an educator. There are many positives to collaboration but communication is essential. We all have different perspectives, and ideas and when people meet, conflict can arise because of the many differences. Furthermore, the personality of teachers can also clash when a group meets. As a teacher leader, it is important to understand colleagues and that can be†¦ Teaching a specialism of any matter requires the teacher themselves to be competent and confident with their own abilities first. To be a competent carpenter requires lots of experience, dedication and time – without dedication, you will not put in the time and in turn not gain the experience. Hence dedication is a fundamental element, which is expressed to all the construction students at Harlow College, in order for them to succeed. Dedication goes hand in hand with motivation, motivation is developed†¦ are three examples of ways a teacher can build a positive relationship with students: a. Making clear relationship between student and teacher is one of respect. This important so the student knows that you are their mentor and you are on their team. You want them to be successful and see it through that they are successful. Always be the student’s personal cheerleader! b. Knowing about the student’s home life is important when building a relationship with the student. By knowing about the student’s†¦ Teacher relationship and the effects on students At a young age, children are molded by the adults around them, shaping how they socially develop and their cognitive development. Once the child is at a school age, the most important adult around them beside family is their teacher. Thus the teacher-student relationship is formed and it must be a positive atmosphere to ensure the child to grow mentally and emotionally. Student-teacher relationships are studied and is found to have a correlation with†¦ Student-Teacher Relationships Create Positive Learning Environments When it comes to the topic of education, most of us will readily agree that a positive connection with a teacher is an essential part of learning and growing as a student. Where this agreement usually ends, however, is on the question of will positive student-teacher relationships improve student behavior? While administrators are convinced that strict discipline is the only answer for classrooms, psychologists believe that positive†¦ Student teacher relationship is very important inside of a classroom. With this relationship students and teachers will most likely do great inside of the class, but without this relationship students are more likely to not do well. Throughout this semester, I have learned a lot about how any why these relationship is key to the success of both students and teachers. Successful student-relationship enables good outcomes for both students and teachers. According to Mester et al. we must first see†¦ The teacher student relationship is very important for children. Children spend approximately 5 to 7 hours a day with a teacher for almost 10 months. We ask ourselves what is considered a good teacher? All of us have gone through schooling, and if fortunate had a favorite teacher. A positive relationship between the student and the teacher is difficult to establish, but can be found for both individuals at either end. The qualities for a positive relationship can vary to set a learning experience†¦

Maritime Logistics Essay Example | Topics and Well Written Essays - 1500 words - 1

Maritime Logistics - Essay Example Both parties sought to develop a solution meant to avert a strike, which would cause a substantial economic and social impact on East and Gulf Coast citisens and other business stakeholders. One port in eastern Florida employs approximately 64,000 workers on full-time and casual labour jobs. Staging of a strike means that the port will suffer an economic predicament for an indefinite period of time – certainly until authorities address the workers’ issues. According to maritime statistics, the port generates approximately $1 billion daily in form of gross domestic revenue to the US economy. This means that downing of tools by port workers will affect Florida residents because of the $1 billion revenue gap created on a daily basis. Among the stakeholders affected are export merchants involved in production and sale of agricultural produces. Norilsk (2012) argues that prolonged wrangles between workers and employers in the port will affect Florida farmers and other indust rial businesses that depend on the port for business activities. Efforts were made by the Longshoremen Association to pursue federal government into stopping the strike in the event that the parties could not reach an agreement. Despite these efforts, legal proceedings within the Florida judicial system allowed workers to continue with the strike. The courts arrived at this decision after considering the provisions availed by proportionate workers’ right in accordance with the Trade Union Ordinance. Therefore, the next step would be to appraise the economic and social impact that will result from the strike. Ports in Supply Chain Management Maritime technical operations indicate that ports play a significant role in international supply chain management. Supply chain management entails integration of technology, information, and manpower skills in facilitating the movement of products from the producer’s premises to the different types of consumers in the market. Wang (2007) states that the role played by supply chain management at the international business platform became more pronounced as a result of increased globalisation. Currently, these chains enhance synchronisation of business activities between trading partners. Supply chains facilitate flow of goods and information from one region to another. As a result, export companies can acquire relevant information meant to make future business decisions. From an economic perspective, producers will adjust their production likes based on consumer patterns observed in their market segments. On the other hand, consumers will only benefit in their trade relationship if they stay abreast of latest developments within the producers environment. This means that international supply chains are charged with the responsibility of developing and maintaining day-to-day movement of goods and information between trading regions. In the context of international supply chain management, ports play a key role as a source of relevant logistical infrastructure. Ports provide a suitable environment where buyers meet sellers. In this regard, involved stakeholders could adjust their business activities in relation to the dictates of supply and demand witnessed in ports. Supply inclines towards the trends created by the demand of goods and services within the consumer market. In this case, some producers wait

Ancient Art Research Paper Example | Topics and Well Written Essays - 500 words

Ancient Art - Research Paper Example explanation on the manner by which the works of art fit into the context of the time period, as created between 30,000 BCE- 500 CE to be classified as Ancient Art. A research from the three official websites of the (1) The Metropolitan Museum of Art; (2) The Louvre Museum; and (3) The Smithsonian Institution Freer Gallery and Sackler Gallery, generated several suggestions of ancient art. However, given the specified time frame, two works of art fall within the category. One was the Terracotta amphora (jar) from The Metropolitan Museum of Art as it was disclosed to have been created within 490 BC. The other work of art was the Attic Red-Figure Amphora, which was classified as an aryballos, allegedly a perfume container, or a very small jar, which was created within the 500 to 490 BC time frame. These two works of ancient art have similarities in terms of the form, both are receptacles or jars. The Terracotta amphora (jar) was reportedly made from terracotta as the medium; while the Attic Red-Figure Aryballos was made from clay. These works of art were both created within the same time frame, about 490B.C. and shows the red figure as the images within these receptacles. The Terracotta amphora jar had the following dimensions H. 16 5/16 in. or 41.50 cm; while the Attic Red-Figure Aryballos was noted to be smaller with the following dimensions, to wit: H. 8.8 cm; or 8.6 cm. Both background colors were predominantly black to enhance the color red figures. Both the Terracotta amphora jar and the Attic Red-Figure Aryballos were was noted to be from the Ancient Greek culture. Both are also representational objects, where the former was noted to be apparently used for decorative purposes; while the latter was a perfume container, which was reportedly hanged in the wrists of athletes (Attic Red-Figure Aryballos). It was described in the first art work that the image was supposed to represent the â€Å"a musician in a long, slim garment accompanies himself on the kithara, a

Cinematography of the film Casablanca Essay Example | Topics and Well Written Essays - 750 words

Cinematography of the film Casablanca - Essay Example Edeson helped director Michael Curtiz in visualizing by focusing on the shadows and maximizing the use of proper lighting and angles. Wide-angle shots are placed in the beginning scenes giving importance to the place of Casablanca and how a German plane flies behind the sign for Rick's Cafe. The wide shot of the planes just over the cafe shows how important this place will be in the next parts of the story. An establishing shot will soon be noticed as camera angles focuses inside Rick’s cafe as if the audience were walking inside for the first time, giving wide angle shots of the patrons inside the club. Some medium shots are placed on individual characters such as the colored man piano player, until an extreme close up shot of a slip of paper is shown with an â€Å"OK† sign by Rick. Here it is established that Rick is an important man, in a medium shot, he is shown slowly puffing a cigarette. The shots through out the scenes create such continuity and gives credibility to the empty life of Rick. The intensity of the setting in a neutral country of Morocco is established with the mix of characters from the Allied forces and the Germans. It also creates an impression on how â€Å"all is fair in love and war† as what the story line would develop. There is also a use of proper lighting maximized with the proper dà ©cor to create at 1940’s kind of American cafà © with live band and gambling, but still the production team maintained certain props to make sure that the audience would remember that it is still in Morocco like the Islamic architecture that remains obvious in the interior. There is heightened use of lighting to create shadows especially to give focus on melancholic state like after curfew encounters at Rick’s cafe with Renault as he searches for money or documents. It creates a touch of mystery establishing that the main character Rick is an amoral man who after a painful heartbreak has remained to be neutral and cynical. He is portrayed as a bitter and sad man, as focused on the medium and close up shots of a face that seems to be sad and old despite earthly success. He moves slow and somehow gloomy with the background of shadows and smoke that surrounds his cafe. As for Iisa the leading lady, angles are focused on her sad and somehow glowing face with eyes that appears to be always in tears. The musical score also creates an impression. Most part of the film revolves around the song â€Å"As Time Goes By† as it somehow relives a memorable time in Paris by both Rick and Iisa. Songs from the 1930’s to the 1940’s are also el oquently highlighted and combined with national anthems from France and Germany, The audience are reminded that this is not just another love story, it maintains the political issues of World War II. Bogart plays a superb role of a romantic leading man, the sad and indifferent bad boy ruined by a past love. At first he seems to be the typical strong man, full of machismo and ego without caring for anyone in the world but himself. But a sense of humanity is shown by how he treats his employees such as Sam, the piano player. As Bergman enters the scene, we notice that indeed this could be the woman that has created all this illusion. When Sam had an encounter with Iisa, he pretends to have never met her before. It is obvious then that this woman would be someone important. Bergman portrays the role of Iisa with so much justice. The focus on her soft face makes a

Aerobic Cellular Respiration in Isolated Mitochondria of Lima Bean Lab Report

Aerobic Cellular Respiration in Isolated Mitochondria of Lima Bean Seeds - Lab Report Example During aerobic respiration, oxygen in the air is used as the final electron receptor which subsequently gets reduced to water. Energy is generated during this process in the form of a high energy molecule, adenosine triphosphate (ATP). This is a complex process involving a series of reactions that use many chemicals and enzymes. Glucose is the most preferred source for cellular respiration and as reported by Rich (2003), it release high energy (29-30 ATP molecules per glucose molecule) during aerobic respiration. Aerobic respiration consists of 3 major steps as glycolysis, Krebs cycle (Citric acid cycle) and electron transport chain. During glycolysis, pyruvate is produced by glucose which is converted to a 2C molecule, acetyl-CoA. Acetyl-CoA combines with the 4C oxaloacetate (last product of the previous Krebs cycle) to produce citrate which is a very high energy source. During the Krebs cycle, citrate is consumed in an 8-step process to release this energy (electrons). Here, the co enzymes FAD (flavin adenine dinucleotide) and NAD+ (nicotinamide adenine dinucleotide) gets reduced to produce a small quantity of carbon dioxide and ATP. Therefore, hydrogen electrons coming from glucose will reduce FAD and NAD+ to FADH2 and NADH + H+ respectively. These electrons then enter the electron transport chain to get oxidized and produce ATP. ... This reaction is catalyzed by the enzyme succinic dehydrogenase using FAD as co-enzyme. In this reaction, 2 hydrogen atoms are removed from succinate and transfer to FAD thereby reducing it to FADH2. DPIP (2, 6-dichloro-phenol-indophenol) blue dye can act as a hydrogen molecule acceptor instead of FAD during this reaction. When DPIP receive hydrogen from succinate, blue color get decolorized. Thus the DPIP color change from blue to colorless is an indication of the level of enzyme activity in the mitochondria which can be measured and recorded with a spectrophotometer. The Krebs cycle is influenced by competitive and noncompetitive inhibitors. Competitive inhibitors compete with the substrate to bind to the active site of the enzyme and this can be overcome by providing more quantity of substrate molecules. Conversely, noncompetitive inhibitors such as metal ions (copper, Cu2+ and mercury, Hg2+) will deactivate the enzyme thereby making it impossible to return back to the reaction. T herefore, the reaction cannot be reactivated by incorporation of more substrate. In the succinate-to-fumarate reaction of the Krebs cycle, Malonate act as a competitive inhibitor on succinate molecule. Molecule shape of malonate is similar to succinate molecule and thus it obstructs the conversion reaction of succinate to fumarate by binding to active site of the enzyme succinate dehydrogenase. However, as described in Zeevalk, Derr-Yellin and Nicklas (1995) it will not react further and result in the termination of the reaction. Therefore FAD will not reduce to FADH2 and fumarate will not be produced, thus arresting the Krebs cycle. As malonate is a competitive inhibitor, the reaction can be

Should Animals Be Used In Medical Research Essay

Should Animals Be Used In Medical Research - Essay Example According to the paper ‘morality’, ‘rights’ and ‘ethics’ are part of philosophy and not of ‘survival instinct’. Millions of people would have either died or would have lived ill lives if the progress in the medical field was not made. Hence, even though use of animals in medical research is violation of animal rights, it is nothing but a different form of ‘fight or flight’ instinct used by human beings to survive the threat to their lives through diseases and health problems. Hence, human beings have every right to use animals in medical research as they are genetically programmed to ‘survive’ any threat and through any means, as they are the part of the natural system where ‘survival of the fittest’ is an accepted law of nature. This paper gives a strong opinion that a healthy body, mind and a soul are foundation of healthy and happy life of human beings. With advent of machines and computers, the physical exertion of human beings have reduced to a great extend. People have become lethargic, physically inactive and dependent on machines to do most of their work. It concluded that humans would have replaced the animals in laboratories for medical research and would have died unnecessarily. The number of the inventions and the discoveries that were made in the medical world with the help of animals shows how important the use of animals is in the medical research. Sadly, most of the discoveries and inventions were possible only because animals were used in the laboratories and researches. Improvement In Quality And Quantity Of Human Life The development of different methods to cure and prevent diseases in humans and animals, in last 100 years, has been possible because of animal experiments in medical research (Giridharan, Kumar & Muthuswamy, 2000, p.1). In last four centuries, major advances in basic research and medical treatments have been achieved only because of the experiments on animals (Giridharan,

Environmental Audit Essay Example | Topics and Well Written Essays - 750 words

Environmental Audit - Essay Example This paper is focused upon environmental audit and how important it is for an organization. It would elaborate on the environmental policies of 3M. Moreover it would shed light upon how 3M followed sustainable practices. Discussion Anything that impinges on the firm can be included in the environment. The environment is not stable; in fact, it is increasingly turbulent due to the era of change and uncertainty in which we live. Changes are happening faster and faster, requiring continual response on the part of businesses. Thereby, it is becoming increasingly imperative for companies to carry out feasibility studies and environmental audits to assess the nature of the new market and plan the strategies accordingly. Environmental audit is the process by which the company’s environmental performance is tested based upon the various environmental policies and strategies that are implemented. The environmental policies and objectives of an organization are clearly stated and docume nted even if they are not followed as rigorously. The audit is carried out based on tests that study the documentation, the policies, work manuals and other material, observation of work practices, and other tests that ensure compliance to the policies and legal requirements. According to the International Chamber of Commerce environmental audit is defined as â€Å"a management tool that ensures a methodical, documented, regular and objective assessment of how an organization is performing in its aims to maintain and protect the environment through controlling management of environmental practices and evaluating the conformity with the policies of the company† (Environmental Auditing, 2004) Environmental audit is a done in a structured and organized manner in order to manage environmental and sustainability issues. It must be supported through the documentation so that verification and validation is carried out effectively at any point in time. The purpose and idea behind an environmental audit is to assess the performance of an organization in terms of its environmental management and equipment. There are various types of environmental audits including environmental management audit, environmental compliance audit, environmental assessment audit, waste audits, environmental due diligence audits and supplier audits. I formerly worked at 3M US which is one of the top companies when it comes to environmental sustainability. It has been at the forefront from the beginning when it comes to adopting programs and policies to ensure environmental protection, social responsibility and economic vitality. The legal structure of the US also has influence over the companies and ensures that environmental policies that are stated are properly followed and implemented. The environmental protection agency (EPA) had strong compliance and conformity principles. At 3M the environmental audit is conducted by the company’s lawyers. The information of the audit is ke pt confidential and not issued until court orders are received. The approach of audit is been changed by the USEPA to go towards ‘self-policing’. Self audit is considered a better option as it allows the companies to reduce any potential legal costs by a great amount. 3M had high regards for sustainability and gave precedence to the sustainable practices. The sustainable practices policies of 3M were in line with the overall corporate policies and values. 3M

Civil Engineering Essay Example for Free

Civil Engineering Essay Introduction This research aims to identify and highlight the career opportunities awaiting fresh graduates of civil engineering. This research further aims to look at the specific jobs that are available for them, amount of work load, basic salaries and evaluate the advantages and disadvantages of particular choice of specialized civil engineering practice such as structural, water resources, environmental, construction, transportation and geo-technical engineering, among others. Statement of the Problem With the wide variety of specialized practice of civil engineering, newly graduated civil engineers need to be aware of the requirements of each specialization and fully understand the other details of the job. Being fresh from the realms of the academe, these fresh civil engineering graduates need to be guided accordingly as they ready to join the civil engineering workforce. Presenting the result of this study will help them evaluate their specific areas of interest within the bounds of the civil engineering career and will enable them to make an intelligent choice as to what career they really want to pursue. Proposed Solution This study will employ in-depth analysis of the career opportunities and choices available for civil engineering graduates. As such, specialized civil engineering fields will be identified and explained, the likeability that a new graduate will pursue a specific field will be determined and the factors that should be considered in choosing a specific career path. Methods In order to address the research problem, the researcher will employ quantitative and qualitative research method which is designed to complement each other’s findings. Respondents of the research will be practicing civil engineers. Using the qualitative research design, the researcher will conduct a survey to compare factors such as the specialized field where civil engineers usually get for their first job and the basic salary offer for an entry level position. The qualitative research design will include in-depth interviews of practitioners on the specifics of their jobs, the factors that should be considered in choosing a line of practice and other pertinent information about the field based on their experience. Conclusion This research aims to help fresh civil engineering graduates in making a decision of which career path to pursue after college by presenting the choices available for them along with the considerations and factors that might affect their decision. First hand data will be gathered through survey and interview of practicing civil engineers specialized in different fields to get information based on their experience.

Radiation Protection for Angiography Procedure.

Radiation Protection for Angiography Procedure. Fluoroscopic procedure produces the greatest patient radiation exposure rate in diagnostic radiology. Therefore the radiation protection in fluoroscopy is very important. Several feature and techniques in fluoroscopy are designed for protection to the patient during fluoroscopic procedure. a) Protection to Patient * A dead-man switch is a device (switch) constructed so that a circuit closing contact can only be maintained by continuous pressure on the switch by the operator. Therefore, when the machine is turned on by any means, whether by the push button at the control panel, or by the foot pedal, this switch must be held in for the machine to remain on. * The on-time of the fluoroscopic tube must be controlled by a timing device, and must end alarm when the exposure exceeds 5 minutes. An audible signal must alert the user to the completion of the preset on time. This signal will remain on until the timing device is reset. * The X-ray tube used for fluoroscopic must not produce X-rays unless a barrier is in position to intercept the entire cross-section of the useful beam. The fluoroscopic imaging assembly must be provided with shielding sufficient that the scatter radiation from the useful beam is minimized. * Protective barriers of at least 0.25 mm lead equivalency must be used to attenuate scatter radiation above the tabletop. This shielding does not replace the lead garments worn by personnel. Scattered radiation under the table must be attenuated by at least 0.25 mm lead equivalency shielding. * Additionally, most c-arm fluoroscopes have a warning beeper or light that activate when the beam is on, some have both. Never inactivate any warning devices, and keep ones foot off the foot pedal whenever possible. * Methods of limiting radiation exposure include: o making certain that the fluoroscopy unit is functioning properly through routine maintenance, o limiting fluoroscopic exposure time, o reducing fields of exposure through collimation, o keeping the X-ray source under the table by avoiding cross-table lateral visualization when possible, and o bringing the image intensifier down close to the patient b) Protection to personnel There are therefore three basic ways to minimize dose: * Reduce time of exposure * Use the inverse square law-doubling your distance away quarter your exposure * Use shielding by barrier These basics known as Cardinal Principle which is important to achieved ALARA. i) Time Radiation dose is directly proportional to the time, those by doubling the radiation time the dose is doubled and by having the radiation time the doses halved. Many factors impact the on time of a fluoroscopic procedure. The exposure time is related to radiation exposure and exposure rate (exposure per unit time) as follows: Exposure time = Exposure/Exposure rate Exposure = Exposure rate x time The algebraic expressions simply imply that if the exposure time is kept short, then the resulting dose to the individual is small. Method of reducing exposure time include meticulous advanced planning of the procedure, judicious use of contrast enhancement, appropriate positioning of the patient, orientation of the fluoroscope unit prior to beginning the procedure. ii) Distance The second radiation protection action relates to the distance between the source of radiation and the exposed individual. The exposure to the individual decreases inversely as the square of the distance. This is known as the inverse square law, which is stated mathematically as: where I is the intensity of radiation and d is the distance between the radiation source and the exposed individual. For example, when the distance is doubled the exposure is reduced by a factor of four. In mobile radiography, where there is no fixed protective control booth, the technologist should remain at least 2 m from the patient, the x-ray tube, and the primary beam during the exposure. In this respect, the ICRP (1982), as well as the NCRP (1989a), recommended that the length of the exposure cord on mobile radiographic units be at least 2 m long. Another important consideration with respect to distance relates to the source-to-image receptor distance (SID). The appropriate SIDs for various examinations must always be maintained because an incorrect SID could mean a second exposure to the patient. Long SID results in less divergent beam and thus decreases the concentration of photons in the patients. Short SID results in the reverse action and increases the patient dose. Hence the longest possible SID should be employed in examinations. However, if a greater than standard SID is used then greater intensity of radiation would be required to produce the same film density. Therefore it is recommended that only standard SIDs should be used. iii) Shielding Shielding procedure the most utilitarian results in the reduction of staff dose as there are times when the procedure list simply must function in close proximity, even directly cines fluoroscopy. In these circumstances there simply is no substitute for the best modern flexible lead gloves, lead glasses, lightweight lead apron and lead lined thyroid shield available. Appropriate shielding is mandatory for the safe use of ionizing radiation for medical imaging. Other method of shielding includes beam collimation, protective drapes and panels. Shielding of occupational workers can be achieved by following methods: * Personnel should remain in the radiation environment only when necessary (step behind the control booth, or leave the room when practical) * The distance between the personnel and the patient should be maximized when practical as the intensity of radiation decreases as the square of distance (inverse square law). * Shielding apparel should be used as and when necessary which comprise of lead aprons, eye glasses with side shields, hand gloves and thyroid shields. Lead aprons are shielding apparel recommended for use by radiation workers. These are classified as a secondary barrier to the effects of ionizing radiation. These aprons protect an individual only from secondary (scattered) radiation, not the primary beam. The thickness of lead in the protective apparel determines the protection it provides. It is known that 0.25 mm lead thickness attenuates 66% of the beam at 75kVp and 1mm attenuates 99% of the beam at same kVp. It is recommended that for general purpose radiography the minimum thickness of lead equivalent in the protective apparel should be 0.5mm. It is recommended that women radiation workers should wear a customized lead apron that reaches below mid thigh level and wraps completely around the pelvis. This would eliminate an accidental exposure to a concept us. Other protective apparel included eye glasses with side shields, thyroid shields and hand gloves. The minimum protective lead equivalents in hand gloves and thyroid shields should be 0.5mm. Lead lined glass and thyroid shield likewise reduce 90% of the exposure to the eyes and thyroid respectively. Lead lined gloves reduce radiation exposure to the hands; however they are no substitute for strict observation of appropriate fluoroscopic hygiene. Gloves should be considered as an effective means of reducing scatter radiation only. 2. State five clinical indications for the patient undergo the angiography procedure. 3. Explain the patient care management before, during and after the procedure Before a procedure: * Patients undergoing an angiogram are advised to stop eating and drinking eight hours prior to the procedure. * They must remove all jewelry before the procedure and change into a hospital gown. * If the arterial puncture is to be made in the armpit or groin area, shaving may be required. * A sedative may be administered to relax the patient for the procedure. * An IV line will also be inserted into a vein in the patients arm before the procedure begins in case medication or blood products are required during the angiogram. * Be aware of and follow all Local Rules and protocols * Prior to the angiography procedure, patients will be briefed on the details of the test, the benefits and risks, and the possible complications involved, and asked to sign an informed consent form. * Ensure that all exposures are justified and there is informed consent * Check patient identity * Position patient comfortably flat, with arm above head where possible * Ensure all members of staff in room are wearing suitable. For operations this should be lead glasses, thyroid collar and wrap-around lead apron * Check all staff are wearing radiation monitors correctly * Use all available lead shielding appropriately sited * Position table before screening * Keep tube current as low as possible and kVp as high as possible for cardiac studies, 60 – 90 kV is appropriate * Keep x ray tube at maximum and image intensifier / receptor at minimum distance from patient * Check all staff are as far away as possible in their role * Use dose reduction programmers when possible * Perform acquisitions on full inspiration where possible * Collimate closely to area of interest * Prolonged procedures: reduce dose to the irradiated skin eg. Change beam angulations * Minimize fluoroscopy time, high dose rate time and no of acquisitions * Remember software features, such as replay fluoro to minimize dose * Dont over use geometric magnification * Remove grid for small patients or when image intensifier / detector cannot be placed close to patient * Check and record screening time and DAP at the end of the case and review against the DRL. During the procedure: * The radiologic technologist will position you on the exam table. A radiologist a physician who specializes in the diagnostic interpretation of medical images will administer a local anesthetic and then make a small nick in your skin so that a thin catheter can be inserted into an artery or vein. The catheter is a flexible, hollow tube about the size of a strand of spaghetti. It usually is inserted into an artery in your groin, although in some cases your arm or another site will be selected for the catheter. * The radiologist will ease the catheter into the artery or vein and gently guide it to the area under investigation. The radiologist will be able to watch the movement of the catheter on a fluoroscope, which is an x-ray unit combined with a television monitor. * When the catheter reaches the area under study, the contrast agent will be injected through the catheter. By watching the fluoroscope screen, the radiologist will be able to see the outline of your blood vessels and identify any blockages or other irregularities. * Angiography procedures can range in time from less than an hour to three hours or more. It is important that you relax and remain as still as possible during the examination. The radiologic technologist and radiologist will stay in the room with you throughout the procedure. If you experience any difficulty, let them know. * Angiography also can be performed using magnetic resonance instead of x-rays to produce images of the blood vessels; this procedure is known as magnetic resonance angiography (MRA) or magnetic resonance venography (MRV). After the procedure: * Because life-threatening internal bleeding is a possible complication of an arterial puncture, an overnight stay in the hospital is sometimes recommended following an angiography procedure, particularly with cerebral and coronary angiograms. * If the procedure is performed on an outpatient basis, the patient is typically kept under close observation for a period of at six to 12 hours before being released. * If the arterial puncture was performed in the femoral artery, the patient will be instructed to keep his leg straight and relatively immobile during the observation period. * The patients blood pressure and vital signs will be monitored and the puncture site observed closely. Pain medication may be prescribed if the patient is experiencing discomfort from the puncture, and a cold pack is applied to the site to reduce swelling. It is normal for the puncture site to be sore and bruised for several weeks. * The patient may also develop a hematoma, a hard mass created by the blood vessels broken during the procedure. Hematomas should be watched carefully, as they may indicate continued bleeding of the arterial puncture site. * Angiography patients are also advised to enjoy two to three days of rest and relaxation after the procedure in order to avoid placing any undue stress on the arterial puncture. Patients who experience continued bleeding or abnormal swelling of the puncture site, sudden dizziness, or chest pains in the days following an angiography procedure should seek medical attention immediately. * Patients undergoing a fluorescein angiography should not drive or expose their eyes to direct sunlight for 12 hours following the procedure. 4. Identify the type of contrast medium, the dose and delivering technique in angiography procedure. * Reducing radiation doses to the patient also generally reduces doses to the medical personnel. Â · Angiography procedure is using fluoroscopy imaging technique which is a real-time imaging technique. 5. List down the catheters and guide wires inclusive of size, shape and the hole type that are used in angiography procedures. The use of lead gloves during procedures is unusual as they are cumbersome and difficult to work in. The automatic brightness control will increase the exposure to go through two layers and one only protects the hand, so if they are going to be used a programme that sets the radiation factors rather than allowing adjustment may be appropriate. In practice, with careful collimation and attenuation to detail it should not necessary for the operators hand to be in the primary beam and only close to it for short periods. While doing catheterization, radiologist should do it behind the lead glass viewer which consists of lead equivalent glass of 0.25mm thickness. Geometric consideration is one of the important things in angiography because source of exposure to personnel is mainly from scattered radiation from the patient. So, it is important to minimize the amount of scattered radiation to personnel. This can be achieved by geometric consideration involving the x-ray tube, patient and image intensifier. The image intensifier should be as close as possible to patient to minimize the amount of scattered radiation hitting personnel. Because in angiography room is sterile for all things, personnel such as radiologist, nurses, radiographer or student should wear shoes which are prepared only. Make sure that film badges always outside personnel body to measure the dose receive to the personnel. The most important thing to remember is that all individuals should be fully trained and learned to be responsible for radiation safety. Involvement of a radiation expert is essential and is particularly useful in equipment specification, assessment and quality assurance, but also in the formulation of Local Rules. Technique Reduces Physician Radiation Exposure During Angiography Current technique requires that physicians performing radiation procedures wear lead gowns. The new technique involves use of a body length floor mounted lead plastic panel to protect to physicians as they monitor patients angiograms and control exam table movement. An extension bar allows the physician to remain safely behind the shield and still retain table control for panning. In the study, researchers recorded radiation exposure to various parts of a physicians body during 25 coronary angiography procedures and compared those results with radiation exposure during angiography on 25 patients using conventional radiation protection. A lead apron, thyroid shield, eyeglasses and facemask were used in both techniques, but a ceiling mounted shield was used in the conventional technique. The researchers placed radiation badges outside and inside the facemask; outside and inside the thyroid shield; on the right and left arm; outside and inside the lead apron; and on the right and left leg. The new equipment resulted in a 90 percent reduction in radiation exposure to the physicians head, arms, and legs. Exposure of the thyroid and torso was minimal with both techniques. Enhanced physician radiation protection during coronary angiography is readily achievable with this new technique, said Martin Magram, M.D., of the University of Maryland Medical Center in Baltimore, Md. Dr. Magram presented the study results on May 3 at the American Roentgen Ray Society Annual Meeting in Vancouver, British Columbia. Dr. Magram pointed out that by freeing physicians from the need to wear lead gowns, the new technique could preserve their ability to benefit patients. It may extend by years their ability to apply the skills they have developed over long careers of serving patients, noted Dr. Magram. New methods of radiation protection must parallel the development of new radiation techniques, added Dr. Magram. The key is to limit medical workers radiation exposure with effective and easy-to-use techniques, and the use of this extension bar and lead plastic shield may be such a technique. Definition Angiography is the x-ray study of the blood vessels. An angiogram uses a radiopaque substance, or dye, to make the blood vessels visible under x ray. Arteriography is a type of angiography that involves the study of the arteries. Purpose Angiography is used to detect abnormalities or blockages in the blood vessels (called occlusions) throughout the circulatory system and in some organs. The procedure is commonly used to identify atherosclerosis; to diagnose heart disease; to evaluate kidney function and detect kidney cysts or tumors; to detect an aneurysm (an abnormal bulge of an artery that can rupture leading to hemorrhage), tumor, blood clot, or arteriovenous malformations (abnormals tangles of arteries and veins) in the brain; and to diagnose problems with the retina of the eye. It is also used to give surgeons an accurate map of the heart prior to open-heart surgery, or of the brain prior to neurosurgery. Precautions Patients with kidney disease or injury may suffer further kidney damage from the contrast mediums used for angiography. Patients who have blood clotting problems, have a known allergy to contrast mediums, or are allergic to iodine, a component of some contrast mediums, may also not be suitable candidates for an angiography procedure. Because x rays carry risks of ionizing radiation exposure to the fetus, pregnant women are also advised to avoid this procedure. Description Angiography is usually performed at a hospital by a trained radiologist and assisting technician or nurse. It takes place in an x-ray or fluoroscopy suite, and for most types of angiograms, the patients vital signs will be monitored throughout the procedure. Angiography requires the injection of a contrast dye that makes the blood vessels visible to x ray. The dye is injected through a procedure known as arterial puncture. The puncture is usually made in the groin area, armpit, inside elbow, or neck. The site is cleaned with an antiseptic agent and injected with a local anesthetic. First, a small incision is made in the skin to help the needle pass. A needle containing an inner wire called a stylet is inserted through the skin into the artery. When the radiologist has punctured the artery with the needle, the stylet is removed and replaced with another long wire called a guide wire. It is normal for blood to spout out of the needle before the guide wire is inserted. The guide wire is fed through the outer needle into the artery and to the area that requires angiographic study. A fluoroscopic screen that displays a view of the patients vascular system is used to pilot the wire to the correct location. Once it is in position, the needle is removed and a catheter is slid over the length of the guide wire until it to reaches the area of study. The guide wire is removed and the catheter is left in place in preparation for the injection of the contrast medium, or dye. Depending on the type of angiography procedure being performed, the contrast medium is either injected by hand with a syringe or is mechanically injected with an automatic injector connected to the catheter. An automatic injector is used frequently because it is able to propel a large volume of dye very quickly to the angiogram site. The patient is warned that the injection will start, and instructed to remain very still. The injection causes some mild to moderate discomfort. Possible side effects or reactions include headache, dizziness, irregular heartbeat, nausea, warmth, burning sensation, and chest pain, but they usually last only momentarily. To view the area of study from different angles or perspectives, the patient may be asked to change positions several times, and subsequent dye injections may be administered. During any injection, the patient or the camera may move. Throughout the dye injection procedure, x-ray pictures and/or fluoroscopic pictures (or moving x rays) will be taken. Because of the high pressure of arterial blood flow, the dye will dissipate through the patients system quickly, so pictures must be taken in rapid succession. An automatic film changer is used because the manual changing of x-ray plates can eat up valuable time. Once the x rays are complete, the catheter is slowly and carefully removed from the patient. Pressure is applied to the site with a sandbag or other weight for 10-20 minutes in order for clotting to take place and the arterial puncture to reseal itself. A pressure bandage is then applied. Most angiograms follow the general procedures outlined above, but vary slightly depending on the area of the vascular system being studied. A variety of common angiography procedures are outlined below: Cerebral angiography Cerebral angiography is used to detect aneurysms, blood clots, and other vascular irregularities in the brain. The catheter is inserted into the femoral or carotid artery and the injected contrast medium travels through the blood vessels on the brain. Patients frequently experience headache, warmth, or a burning sensation in the head or neck during the injection portion of the procedure. A cerebral angiogram takes two to four hours to complete. Coronary angiography Coronary angiography is administered by a cardiologist with training in radiology or, occasionally, by a radiologist. The arterial puncture is typically given in the femoral artery, and the cardiologist uses a guide wire and catheter to perform a contrast injection and x-ray series on the coronary arteries. The catheter may also be placed in the left ventricle to examine the mitral and aortic valves of the heart. If the cardiologist requires a view of the right ventricle of the heart or of the tricuspid or pulmonic valves, the catheter will be inserted through a large vein and guided into the right ventricle. The catheter also serves the purpose of monitoring blood pressures in these different locations inside the heart. The angiogram procedure takes several hours, depending on the complexity of the procedure. Pulmonary angiography Pulmonary, or lung, angiography is performed to evaluate blood circulation to the lungs. It is also considered the most accurate diagnostic test for detecting a pulmonary embolism. The procedure differs from cerebral and coronary angiograms in that the guide wire and catheter are inserted into a vein instead of an artery, and are guided up through the chambers of the heart and into the pulmonary artery. Throughout the procedure, the patients vital signs are monitored to ensure that the catheter doesnt cause arrhythmias, or irregular heartbeats. The contrast medium is then injected into the pulmonary artery where it circulates through the lung capillaries. The test typically takes up to 90 minutes. Kidney angiography Patients with chronic renal disease or injury can suffer further damage to their kidneys from the contrast medium used in a kidney angiogram, yet they often require the test to evaluate kidney function. These patients should be well-hydrated with a intravenous saline drip before the procedure, and may benefit from available medications (e.g., dopamine) that help to protect the kidney from further injury due to contrast agents. During a kidney angiogram, the guide wire and catheter are inserted into the femoral artery in the groin area and advanced through the abdominal aorta, the main artery in the abdomen, and into the renal arteries. The procedure will take approximately one hour. Fluorescein angiography Fluorescein angiography is used to diagnose retinal problems and circulatory disorders. It is typically conducted as an outpatient procedure. The patients pupils are dilated with eye drops and he rests his chin and forehead against a bracing apparatus to keep it still. Sodium fluorescein dye is then injected with a syringe into a vein in the patients arm. The dye will travel through the patients body and into the blood vessels of the eye. The procedure does not require x rays. Instead, a rapid series of close-up photographs of the patients eyes are taken, one set immediately after the dye is injected, and a second set approximately 20 minutes later once the dye has moved through the patients vascular system. The entire procedure takes up to one hour. Celiac and mesenteric angiography Celiac and mesenteric angiography involves x-ray exploration of the celiac and mesenteric arteries, arterial branches of the abdominal aorta that supply blood to the abdomen and digestive system. The test is commonly used to detect aneurysm, thrombosis, and signs of ischemia in the celiac and mesenteric arteries, and to locate the source of gastrointestinal bleeding. It is also used in the diagnosis of a number of conditions, including portal hypertension, and cirrhosis. The procedure can take up to three hours, depending on the number of blood vessels studied. Splenoportography A splenoportograph is a variation of an angiogram that involves the injection of contrast medium directly into the spleen to view the splenic and portal veins. It is used to diagnose blockages in the splenic vein and portal vein thrombosis and to assess the strength and location of the vascular system prior to liver transplantation. Most angiography procedures are typically paid for by major medical insurance. Patients should check with their individual insurance plans to determine their coverage. Aftercare Risks Because angiography involves puncturing an artery, internal bleeding or hemorrhage are possible complications of the test. As with any invasive procedure, infection of the puncture site or bloodstream is also a risk, but this is rare. A stroke or heart attack may be triggered by an angiogram if blood clots or plaque on the inside of the arterial wall are dislodged by the catheter and form a blockage in the blood vessels or artery. The heart may also become irritated by the movement of the catheter through its chambers during pulmonary and coronary angiography procedures, and arrhythmias may develop. Patients who develop an allergic reaction to the contrast medium used in angiography may experience a variety of symptoms, including swelling, difficulty breathing, heart failure, or a sudden drop in blood pressure. If the patient is aware of the allergy before the test is administered, certain medications can be administered at that time to counteract the reaction. Angiography involves minor exposure to radiation through the x rays and fluoroscopic guidance used in the procedure. Unless the patient is pregnant, or multiple radiological or fluoroscopic studies are required, the small dose of radiation incurred during a single procedure poses little risk. However, multiple studies requiring fluoroscopic exposure that are conducted in a short time period have been known to cause skin necrosis in some individuals. This risk can be minimized by careful monitoring and documentation of cumulative radiation doses administered to these patients. Normal results The results of an angiogram or arteriogram depend on the artery or organ system being examined. Generally, test results should display a normal and unimpeded flow of blood through the vascular system. Fluorescein angiography should result in no leakage of fluorescein dye through the retinal blood vessels. Abnormal results Abnormal results of an angiography may display a restricted blood vessel or arterial blood flow (ischemia) or an irregular placement or location of blood vessels. The results of an angiography vary widely by the type of procedure performed, and should be interpreted and explained to the patient by a trained radiologist. Arteriosclerosis A chronic condition characterized by thickening and hardening of the arteries and the build-up of plaque on the arterial walls. Arteriosclerosis can slow or impair blood circulation. Carotid artery An artery located in the neck. Catheter A long, thin, flexible tube used in angiography to inject contrast material into the arteries. Cirrhosis A condition characterized by the destruction of healthy liver tissue. A cirrhotic liver is scarred and cannot break down the proteins in the bloodstream. Cirrhosis is associated with portal hypertension. Embolism A blood clot, air bubble, or clot of foreign material that travels and blocks the flow of blood in an artery. When blood supply to a tissue or organ is blocked by an embolism, infarction, or death of the tissue the artery feeds, occurs. Without immediate and appropriate treatment, an embolism can be fatal. Femoral artery An artery located in the groin area that is the most frequently accessed site for arterial puncture in angiography. Fluorescein dye An orange dye used to illuminate the blood vessels of the retina in fluorescein angiography. Fluoroscopic screen A fluorescent screen which displays moving x-rays of the body. Fluoroscopy allows the radiologist to visualize the guide wire and catheter he is moving through the patients artery. Guide wire A wire that is inserted into an artery to guides a catheter to a certain location in the body. Iscehmia A lack of normal blood supply to a organ or body part because of blockages or constriction of the blood vessels. Necrosis Cellular or tissue death; skin necrosis may be caused by multiple, consecutive doses of radiation from fluoroscopic or x-ray procedures. Plaque Fatty material that is deposited on the inside of the arterial wall. Portal hypertension A condition caused by cirrhosis of the liver. It is characterized by impaired or reversed blood flow from the portal vein to the liver, an enlarged spleen, and dilated veins in the esophagus and stomach. Portal vein thrombosis The development of a blood clot in the vein that brings blood into the liver. Untreated portal vein thrombosis causes portal hypertension. For Your Information Books * Baum, Stanley, and Michael J. Pentecost, eds. Abrams Angiography. 4th ed. Radiation Protection for Angiography Procedure. Radiation Protection for Angiography Procedure. Fluoroscopic procedure produces the greatest patient radiation exposure rate in diagnostic radiology. Therefore the radiation protection in fluoroscopy is very important. Several feature and techniques in fluoroscopy are designed for protection to the patient during fluoroscopic procedure. a) Protection to Patient * A dead-man switch is a device (switch) constructed so that a circuit closing contact can only be maintained by continuous pressure on the switch by the operator. Therefore, when the machine is turned on by any means, whether by the push button at the control panel, or by the foot pedal, this switch must be held in for the machine to remain on. * The on-time of the fluoroscopic tube must be controlled by a timing device, and must end alarm when the exposure exceeds 5 minutes. An audible signal must alert the user to the completion of the preset on time. This signal will remain on until the timing device is reset. * The X-ray tube used for fluoroscopic must not produce X-rays unless a barrier is in position to intercept the entire cross-section of the useful beam. The fluoroscopic imaging assembly must be provided with shielding sufficient that the scatter radiation from the useful beam is minimized. * Protective barriers of at least 0.25 mm lead equivalency must be used to attenuate scatter radiation above the tabletop. This shielding does not replace the lead garments worn by personnel. Scattered radiation under the table must be attenuated by at least 0.25 mm lead equivalency shielding. * Additionally, most c-arm fluoroscopes have a warning beeper or light that activate when the beam is on, some have both. Never inactivate any warning devices, and keep ones foot off the foot pedal whenever possible. * Methods of limiting radiation exposure include: o making certain that the fluoroscopy unit is functioning properly through routine maintenance, o limiting fluoroscopic exposure time, o reducing fields of exposure through collimation, o keeping the X-ray source under the table by avoiding cross-table lateral visualization when possible, and o bringing the image intensifier down close to the patient b) Protection to personnel There are therefore three basic ways to minimize dose: * Reduce time of exposure * Use the inverse square law-doubling your distance away quarter your exposure * Use shielding by barrier These basics known as Cardinal Principle which is important to achieved ALARA. i) Time Radiation dose is directly proportional to the time, those by doubling the radiation time the dose is doubled and by having the radiation time the doses halved. Many factors impact the on time of a fluoroscopic procedure. The exposure time is related to radiation exposure and exposure rate (exposure per unit time) as follows: Exposure time = Exposure/Exposure rate Exposure = Exposure rate x time The algebraic expressions simply imply that if the exposure time is kept short, then the resulting dose to the individual is small. Method of reducing exposure time include meticulous advanced planning of the procedure, judicious use of contrast enhancement, appropriate positioning of the patient, orientation of the fluoroscope unit prior to beginning the procedure. ii) Distance The second radiation protection action relates to the distance between the source of radiation and the exposed individual. The exposure to the individual decreases inversely as the square of the distance. This is known as the inverse square law, which is stated mathematically as: where I is the intensity of radiation and d is the distance between the radiation source and the exposed individual. For example, when the distance is doubled the exposure is reduced by a factor of four. In mobile radiography, where there is no fixed protective control booth, the technologist should remain at least 2 m from the patient, the x-ray tube, and the primary beam during the exposure. In this respect, the ICRP (1982), as well as the NCRP (1989a), recommended that the length of the exposure cord on mobile radiographic units be at least 2 m long. Another important consideration with respect to distance relates to the source-to-image receptor distance (SID). The appropriate SIDs for various examinations must always be maintained because an incorrect SID could mean a second exposure to the patient. Long SID results in less divergent beam and thus decreases the concentration of photons in the patients. Short SID results in the reverse action and increases the patient dose. Hence the longest possible SID should be employed in examinations. However, if a greater than standard SID is used then greater intensity of radiation would be required to produce the same film density. Therefore it is recommended that only standard SIDs should be used. iii) Shielding Shielding procedure the most utilitarian results in the reduction of staff dose as there are times when the procedure list simply must function in close proximity, even directly cines fluoroscopy. In these circumstances there simply is no substitute for the best modern flexible lead gloves, lead glasses, lightweight lead apron and lead lined thyroid shield available. Appropriate shielding is mandatory for the safe use of ionizing radiation for medical imaging. Other method of shielding includes beam collimation, protective drapes and panels. Shielding of occupational workers can be achieved by following methods: * Personnel should remain in the radiation environment only when necessary (step behind the control booth, or leave the room when practical) * The distance between the personnel and the patient should be maximized when practical as the intensity of radiation decreases as the square of distance (inverse square law). * Shielding apparel should be used as and when necessary which comprise of lead aprons, eye glasses with side shields, hand gloves and thyroid shields. Lead aprons are shielding apparel recommended for use by radiation workers. These are classified as a secondary barrier to the effects of ionizing radiation. These aprons protect an individual only from secondary (scattered) radiation, not the primary beam. The thickness of lead in the protective apparel determines the protection it provides. It is known that 0.25 mm lead thickness attenuates 66% of the beam at 75kVp and 1mm attenuates 99% of the beam at same kVp. It is recommended that for general purpose radiography the minimum thickness of lead equivalent in the protective apparel should be 0.5mm. It is recommended that women radiation workers should wear a customized lead apron that reaches below mid thigh level and wraps completely around the pelvis. This would eliminate an accidental exposure to a concept us. Other protective apparel included eye glasses with side shields, thyroid shields and hand gloves. The minimum protective lead equivalents in hand gloves and thyroid shields should be 0.5mm. Lead lined glass and thyroid shield likewise reduce 90% of the exposure to the eyes and thyroid respectively. Lead lined gloves reduce radiation exposure to the hands; however they are no substitute for strict observation of appropriate fluoroscopic hygiene. Gloves should be considered as an effective means of reducing scatter radiation only. 2. State five clinical indications for the patient undergo the angiography procedure. 3. Explain the patient care management before, during and after the procedure Before a procedure: * Patients undergoing an angiogram are advised to stop eating and drinking eight hours prior to the procedure. * They must remove all jewelry before the procedure and change into a hospital gown. * If the arterial puncture is to be made in the armpit or groin area, shaving may be required. * A sedative may be administered to relax the patient for the procedure. * An IV line will also be inserted into a vein in the patients arm before the procedure begins in case medication or blood products are required during the angiogram. * Be aware of and follow all Local Rules and protocols * Prior to the angiography procedure, patients will be briefed on the details of the test, the benefits and risks, and the possible complications involved, and asked to sign an informed consent form. * Ensure that all exposures are justified and there is informed consent * Check patient identity * Position patient comfortably flat, with arm above head where possible * Ensure all members of staff in room are wearing suitable. For operations this should be lead glasses, thyroid collar and wrap-around lead apron * Check all staff are wearing radiation monitors correctly * Use all available lead shielding appropriately sited * Position table before screening * Keep tube current as low as possible and kVp as high as possible for cardiac studies, 60 – 90 kV is appropriate * Keep x ray tube at maximum and image intensifier / receptor at minimum distance from patient * Check all staff are as far away as possible in their role * Use dose reduction programmers when possible * Perform acquisitions on full inspiration where possible * Collimate closely to area of interest * Prolonged procedures: reduce dose to the irradiated skin eg. Change beam angulations * Minimize fluoroscopy time, high dose rate time and no of acquisitions * Remember software features, such as replay fluoro to minimize dose * Dont over use geometric magnification * Remove grid for small patients or when image intensifier / detector cannot be placed close to patient * Check and record screening time and DAP at the end of the case and review against the DRL. During the procedure: * The radiologic technologist will position you on the exam table. A radiologist a physician who specializes in the diagnostic interpretation of medical images will administer a local anesthetic and then make a small nick in your skin so that a thin catheter can be inserted into an artery or vein. The catheter is a flexible, hollow tube about the size of a strand of spaghetti. It usually is inserted into an artery in your groin, although in some cases your arm or another site will be selected for the catheter. * The radiologist will ease the catheter into the artery or vein and gently guide it to the area under investigation. The radiologist will be able to watch the movement of the catheter on a fluoroscope, which is an x-ray unit combined with a television monitor. * When the catheter reaches the area under study, the contrast agent will be injected through the catheter. By watching the fluoroscope screen, the radiologist will be able to see the outline of your blood vessels and identify any blockages or other irregularities. * Angiography procedures can range in time from less than an hour to three hours or more. It is important that you relax and remain as still as possible during the examination. The radiologic technologist and radiologist will stay in the room with you throughout the procedure. If you experience any difficulty, let them know. * Angiography also can be performed using magnetic resonance instead of x-rays to produce images of the blood vessels; this procedure is known as magnetic resonance angiography (MRA) or magnetic resonance venography (MRV). After the procedure: * Because life-threatening internal bleeding is a possible complication of an arterial puncture, an overnight stay in the hospital is sometimes recommended following an angiography procedure, particularly with cerebral and coronary angiograms. * If the procedure is performed on an outpatient basis, the patient is typically kept under close observation for a period of at six to 12 hours before being released. * If the arterial puncture was performed in the femoral artery, the patient will be instructed to keep his leg straight and relatively immobile during the observation period. * The patients blood pressure and vital signs will be monitored and the puncture site observed closely. Pain medication may be prescribed if the patient is experiencing discomfort from the puncture, and a cold pack is applied to the site to reduce swelling. It is normal for the puncture site to be sore and bruised for several weeks. * The patient may also develop a hematoma, a hard mass created by the blood vessels broken during the procedure. Hematomas should be watched carefully, as they may indicate continued bleeding of the arterial puncture site. * Angiography patients are also advised to enjoy two to three days of rest and relaxation after the procedure in order to avoid placing any undue stress on the arterial puncture. Patients who experience continued bleeding or abnormal swelling of the puncture site, sudden dizziness, or chest pains in the days following an angiography procedure should seek medical attention immediately. * Patients undergoing a fluorescein angiography should not drive or expose their eyes to direct sunlight for 12 hours following the procedure. 4. Identify the type of contrast medium, the dose and delivering technique in angiography procedure. * Reducing radiation doses to the patient also generally reduces doses to the medical personnel. Â · Angiography procedure is using fluoroscopy imaging technique which is a real-time imaging technique. 5. List down the catheters and guide wires inclusive of size, shape and the hole type that are used in angiography procedures. The use of lead gloves during procedures is unusual as they are cumbersome and difficult to work in. The automatic brightness control will increase the exposure to go through two layers and one only protects the hand, so if they are going to be used a programme that sets the radiation factors rather than allowing adjustment may be appropriate. In practice, with careful collimation and attenuation to detail it should not necessary for the operators hand to be in the primary beam and only close to it for short periods. While doing catheterization, radiologist should do it behind the lead glass viewer which consists of lead equivalent glass of 0.25mm thickness. Geometric consideration is one of the important things in angiography because source of exposure to personnel is mainly from scattered radiation from the patient. So, it is important to minimize the amount of scattered radiation to personnel. This can be achieved by geometric consideration involving the x-ray tube, patient and image intensifier. The image intensifier should be as close as possible to patient to minimize the amount of scattered radiation hitting personnel. Because in angiography room is sterile for all things, personnel such as radiologist, nurses, radiographer or student should wear shoes which are prepared only. Make sure that film badges always outside personnel body to measure the dose receive to the personnel. The most important thing to remember is that all individuals should be fully trained and learned to be responsible for radiation safety. Involvement of a radiation expert is essential and is particularly useful in equipment specification, assessment and quality assurance, but also in the formulation of Local Rules. Technique Reduces Physician Radiation Exposure During Angiography Current technique requires that physicians performing radiation procedures wear lead gowns. The new technique involves use of a body length floor mounted lead plastic panel to protect to physicians as they monitor patients angiograms and control exam table movement. An extension bar allows the physician to remain safely behind the shield and still retain table control for panning. In the study, researchers recorded radiation exposure to various parts of a physicians body during 25 coronary angiography procedures and compared those results with radiation exposure during angiography on 25 patients using conventional radiation protection. A lead apron, thyroid shield, eyeglasses and facemask were used in both techniques, but a ceiling mounted shield was used in the conventional technique. The researchers placed radiation badges outside and inside the facemask; outside and inside the thyroid shield; on the right and left arm; outside and inside the lead apron; and on the right and left leg. The new equipment resulted in a 90 percent reduction in radiation exposure to the physicians head, arms, and legs. Exposure of the thyroid and torso was minimal with both techniques. Enhanced physician radiation protection during coronary angiography is readily achievable with this new technique, said Martin Magram, M.D., of the University of Maryland Medical Center in Baltimore, Md. Dr. Magram presented the study results on May 3 at the American Roentgen Ray Society Annual Meeting in Vancouver, British Columbia. Dr. Magram pointed out that by freeing physicians from the need to wear lead gowns, the new technique could preserve their ability to benefit patients. It may extend by years their ability to apply the skills they have developed over long careers of serving patients, noted Dr. Magram. New methods of radiation protection must parallel the development of new radiation techniques, added Dr. Magram. The key is to limit medical workers radiation exposure with effective and easy-to-use techniques, and the use of this extension bar and lead plastic shield may be such a technique. Definition Angiography is the x-ray study of the blood vessels. An angiogram uses a radiopaque substance, or dye, to make the blood vessels visible under x ray. Arteriography is a type of angiography that involves the study of the arteries. Purpose Angiography is used to detect abnormalities or blockages in the blood vessels (called occlusions) throughout the circulatory system and in some organs. The procedure is commonly used to identify atherosclerosis; to diagnose heart disease; to evaluate kidney function and detect kidney cysts or tumors; to detect an aneurysm (an abnormal bulge of an artery that can rupture leading to hemorrhage), tumor, blood clot, or arteriovenous malformations (abnormals tangles of arteries and veins) in the brain; and to diagnose problems with the retina of the eye. It is also used to give surgeons an accurate map of the heart prior to open-heart surgery, or of the brain prior to neurosurgery. Precautions Patients with kidney disease or injury may suffer further kidney damage from the contrast mediums used for angiography. Patients who have blood clotting problems, have a known allergy to contrast mediums, or are allergic to iodine, a component of some contrast mediums, may also not be suitable candidates for an angiography procedure. Because x rays carry risks of ionizing radiation exposure to the fetus, pregnant women are also advised to avoid this procedure. Description Angiography is usually performed at a hospital by a trained radiologist and assisting technician or nurse. It takes place in an x-ray or fluoroscopy suite, and for most types of angiograms, the patients vital signs will be monitored throughout the procedure. Angiography requires the injection of a contrast dye that makes the blood vessels visible to x ray. The dye is injected through a procedure known as arterial puncture. The puncture is usually made in the groin area, armpit, inside elbow, or neck. The site is cleaned with an antiseptic agent and injected with a local anesthetic. First, a small incision is made in the skin to help the needle pass. A needle containing an inner wire called a stylet is inserted through the skin into the artery. When the radiologist has punctured the artery with the needle, the stylet is removed and replaced with another long wire called a guide wire. It is normal for blood to spout out of the needle before the guide wire is inserted. The guide wire is fed through the outer needle into the artery and to the area that requires angiographic study. A fluoroscopic screen that displays a view of the patients vascular system is used to pilot the wire to the correct location. Once it is in position, the needle is removed and a catheter is slid over the length of the guide wire until it to reaches the area of study. The guide wire is removed and the catheter is left in place in preparation for the injection of the contrast medium, or dye. Depending on the type of angiography procedure being performed, the contrast medium is either injected by hand with a syringe or is mechanically injected with an automatic injector connected to the catheter. An automatic injector is used frequently because it is able to propel a large volume of dye very quickly to the angiogram site. The patient is warned that the injection will start, and instructed to remain very still. The injection causes some mild to moderate discomfort. Possible side effects or reactions include headache, dizziness, irregular heartbeat, nausea, warmth, burning sensation, and chest pain, but they usually last only momentarily. To view the area of study from different angles or perspectives, the patient may be asked to change positions several times, and subsequent dye injections may be administered. During any injection, the patient or the camera may move. Throughout the dye injection procedure, x-ray pictures and/or fluoroscopic pictures (or moving x rays) will be taken. Because of the high pressure of arterial blood flow, the dye will dissipate through the patients system quickly, so pictures must be taken in rapid succession. An automatic film changer is used because the manual changing of x-ray plates can eat up valuable time. Once the x rays are complete, the catheter is slowly and carefully removed from the patient. Pressure is applied to the site with a sandbag or other weight for 10-20 minutes in order for clotting to take place and the arterial puncture to reseal itself. A pressure bandage is then applied. Most angiograms follow the general procedures outlined above, but vary slightly depending on the area of the vascular system being studied. A variety of common angiography procedures are outlined below: Cerebral angiography Cerebral angiography is used to detect aneurysms, blood clots, and other vascular irregularities in the brain. The catheter is inserted into the femoral or carotid artery and the injected contrast medium travels through the blood vessels on the brain. Patients frequently experience headache, warmth, or a burning sensation in the head or neck during the injection portion of the procedure. A cerebral angiogram takes two to four hours to complete. Coronary angiography Coronary angiography is administered by a cardiologist with training in radiology or, occasionally, by a radiologist. The arterial puncture is typically given in the femoral artery, and the cardiologist uses a guide wire and catheter to perform a contrast injection and x-ray series on the coronary arteries. The catheter may also be placed in the left ventricle to examine the mitral and aortic valves of the heart. If the cardiologist requires a view of the right ventricle of the heart or of the tricuspid or pulmonic valves, the catheter will be inserted through a large vein and guided into the right ventricle. The catheter also serves the purpose of monitoring blood pressures in these different locations inside the heart. The angiogram procedure takes several hours, depending on the complexity of the procedure. Pulmonary angiography Pulmonary, or lung, angiography is performed to evaluate blood circulation to the lungs. It is also considered the most accurate diagnostic test for detecting a pulmonary embolism. The procedure differs from cerebral and coronary angiograms in that the guide wire and catheter are inserted into a vein instead of an artery, and are guided up through the chambers of the heart and into the pulmonary artery. Throughout the procedure, the patients vital signs are monitored to ensure that the catheter doesnt cause arrhythmias, or irregular heartbeats. The contrast medium is then injected into the pulmonary artery where it circulates through the lung capillaries. The test typically takes up to 90 minutes. Kidney angiography Patients with chronic renal disease or injury can suffer further damage to their kidneys from the contrast medium used in a kidney angiogram, yet they often require the test to evaluate kidney function. These patients should be well-hydrated with a intravenous saline drip before the procedure, and may benefit from available medications (e.g., dopamine) that help to protect the kidney from further injury due to contrast agents. During a kidney angiogram, the guide wire and catheter are inserted into the femoral artery in the groin area and advanced through the abdominal aorta, the main artery in the abdomen, and into the renal arteries. The procedure will take approximately one hour. Fluorescein angiography Fluorescein angiography is used to diagnose retinal problems and circulatory disorders. It is typically conducted as an outpatient procedure. The patients pupils are dilated with eye drops and he rests his chin and forehead against a bracing apparatus to keep it still. Sodium fluorescein dye is then injected with a syringe into a vein in the patients arm. The dye will travel through the patients body and into the blood vessels of the eye. The procedure does not require x rays. Instead, a rapid series of close-up photographs of the patients eyes are taken, one set immediately after the dye is injected, and a second set approximately 20 minutes later once the dye has moved through the patients vascular system. The entire procedure takes up to one hour. Celiac and mesenteric angiography Celiac and mesenteric angiography involves x-ray exploration of the celiac and mesenteric arteries, arterial branches of the abdominal aorta that supply blood to the abdomen and digestive system. The test is commonly used to detect aneurysm, thrombosis, and signs of ischemia in the celiac and mesenteric arteries, and to locate the source of gastrointestinal bleeding. It is also used in the diagnosis of a number of conditions, including portal hypertension, and cirrhosis. The procedure can take up to three hours, depending on the number of blood vessels studied. Splenoportography A splenoportograph is a variation of an angiogram that involves the injection of contrast medium directly into the spleen to view the splenic and portal veins. It is used to diagnose blockages in the splenic vein and portal vein thrombosis and to assess the strength and location of the vascular system prior to liver transplantation. Most angiography procedures are typically paid for by major medical insurance. Patients should check with their individual insurance plans to determine their coverage. Aftercare Risks Because angiography involves puncturing an artery, internal bleeding or hemorrhage are possible complications of the test. As with any invasive procedure, infection of the puncture site or bloodstream is also a risk, but this is rare. A stroke or heart attack may be triggered by an angiogram if blood clots or plaque on the inside of the arterial wall are dislodged by the catheter and form a blockage in the blood vessels or artery. The heart may also become irritated by the movement of the catheter through its chambers during pulmonary and coronary angiography procedures, and arrhythmias may develop. Patients who develop an allergic reaction to the contrast medium used in angiography may experience a variety of symptoms, including swelling, difficulty breathing, heart failure, or a sudden drop in blood pressure. If the patient is aware of the allergy before the test is administered, certain medications can be administered at that time to counteract the reaction. Angiography involves minor exposure to radiation through the x rays and fluoroscopic guidance used in the procedure. Unless the patient is pregnant, or multiple radiological or fluoroscopic studies are required, the small dose of radiation incurred during a single procedure poses little risk. However, multiple studies requiring fluoroscopic exposure that are conducted in a short time period have been known to cause skin necrosis in some individuals. This risk can be minimized by careful monitoring and documentation of cumulative radiation doses administered to these patients. Normal results The results of an angiogram or arteriogram depend on the artery or organ system being examined. Generally, test results should display a normal and unimpeded flow of blood through the vascular system. Fluorescein angiography should result in no leakage of fluorescein dye through the retinal blood vessels. Abnormal results Abnormal results of an angiography may display a restricted blood vessel or arterial blood flow (ischemia) or an irregular placement or location of blood vessels. The results of an angiography vary widely by the type of procedure performed, and should be interpreted and explained to the patient by a trained radiologist. Arteriosclerosis A chronic condition characterized by thickening and hardening of the arteries and the build-up of plaque on the arterial walls. Arteriosclerosis can slow or impair blood circulation. Carotid artery An artery located in the neck. Catheter A long, thin, flexible tube used in angiography to inject contrast material into the arteries. Cirrhosis A condition characterized by the destruction of healthy liver tissue. A cirrhotic liver is scarred and cannot break down the proteins in the bloodstream. Cirrhosis is associated with portal hypertension. Embolism A blood clot, air bubble, or clot of foreign material that travels and blocks the flow of blood in an artery. When blood supply to a tissue or organ is blocked by an embolism, infarction, or death of the tissue the artery feeds, occurs. Without immediate and appropriate treatment, an embolism can be fatal. Femoral artery An artery located in the groin area that is the most frequently accessed site for arterial puncture in angiography. Fluorescein dye An orange dye used to illuminate the blood vessels of the retina in fluorescein angiography. Fluoroscopic screen A fluorescent screen which displays moving x-rays of the body. Fluoroscopy allows the radiologist to visualize the guide wire and catheter he is moving through the patients artery. Guide wire A wire that is inserted into an artery to guides a catheter to a certain location in the body. Iscehmia A lack of normal blood supply to a organ or body part because of blockages or constriction of the blood vessels. Necrosis Cellular or tissue death; skin necrosis may be caused by multiple, consecutive doses of radiation from fluoroscopic or x-ray procedures. Plaque Fatty material that is deposited on the inside of the arterial wall. Portal hypertension A condition caused by cirrhosis of the liver. It is characterized by impaired or reversed blood flow from the portal vein to the liver, an enlarged spleen, and dilated veins in the esophagus and stomach. Portal vein thrombosis The development of a blood clot in the vein that brings blood into the liver. Untreated portal vein thrombosis causes portal hypertension. For Your Information Books * Baum, Stanley, and Michael J. Pentecost, eds. Abrams Angiography. 4th ed.