Introduction to Radiation Protection

Transcription

1 CHAPTER 1 Introduction to Radiation Protection OBJECTIVES After completing this chapter, the reader will be able to perform the following: Identify the consequences of ionization in human cells. Give examples of how radiologic technologists and radiologists can exercise control of radiant energy while performing imaging procedures. Discuss the concept of effective radiation protection. Discuss the need to safeguard against significant and continuing radiation exposure. Explain the justification and responsibility for imaging procedures. Explain how diagnostic efficacy of an imaging procedure can be maximized. Explain how imaging professionals can help ensure that both occupational and nonoccupational dose limits remain well below maximum allowable levels. State the ALARA principle and discuss its significance in diagnostic imaging. List employer requirements for implementing and maintaining an effective radiation safety program in a facility that provides imaging services. List the responsibilities that radiation workers must fulfill to maintain an effective radiation safety program. Describe the importance of patient education as it relates to medical imaging. Explain how radiographers should answer patients questions about the risk of radiation exposure from an imaging procedure, and give some examples. Define the terms sievert (Sv) and millisievert (msv). CHAPTER OUTLINE Effective Radiation Protection Need to Safeguard against Significant and Continuing Radiation Exposure Justification and Responsibility for Imaging Procedures Benefit versus Risk Diagnostic Efficacy As Low as Reasonably Achievable (ALARA) Principle Concepts of Radiologic Practice Cardinal Rules of Radiation Protection Responsibility for Maintaining ALARA in the Medical Industry Patient Protection and Patient Education Educating Patients about Imaging Procedures Risk of Imaging Procedure versus Potential Benefit Background Equivalent Radiation Time Tools for Radiation Awareness and Community Education (TRACE) Program Standardized Dose Reporting Summary Copyright 2014, Elsevier Inc. 1

2 2 CHAPTER 1 Introduction to Radiation Protection KEY TERMS as low as reasonably achievable (ALARA) background equivalent radiation time (BERT) biologic effects diagnostic efficacy entrance skin exposure (ESE) ionizing radiation millisievert (msv) occupational and nonoccupational doses optimization for radiation protection (ORP) radiation protection risk sievert (Sv) standardized dose reporting Tools for Radiation Awareness and Community Education (TRACE Program) Although radiation in all its manifestations has been present on our planet since its beginnings, the use of radiation in the healing arts did not begin until the discovery of x-rays in Scientists experimenting with the newly discovered mysterious rays gradually became aware of their value to the medical community both as a diagnostic and as a therapeutic tool. The ability of x-rays to cause injury in normal biologic tissue soon became apparent as well. Hence, since the early 1900s both the beneficial and destructive potentials of x-rays have been known. X-rays are a form of ionizing radiation. When passing through matter, ionizing radiation produces positively and negatively charged particles (ions). The production of these ions is the event that may cause injury in normal biologic tissue. Consequences of ionization in human cells are listed in Box 1-1 and are discussed in Chapter 7 of this text. BOX 1-1 Consequences of Ionization in Human Cells * Creation of unstable atoms Production of free electrons Production of low-energy x-ray photons Creation of reactive free radicals capable of producing substances poisonous to the cell Creation of new biologic molecules detrimental to the living cell Injury to the cell that may manifest itself as abnormal function or loss of function * Each of these consequences is fully discussed in subsequent chapters. By using the knowledge of radiation-induced hazards that has been gained over many years and by employing effective methods to limit or eliminate those hazards, humans can safely control the use of radiant energy. An example of controllable radiant energy is the radiation produced from an x-ray tube ( Fig. 1-1 ). Radiologic technologists and radiologists: Are educated in the safe operation of radiation-producing imaging equipment. Use protective devices whenever possible. Follow established procedures. Select technical exposure factors that significantly reduce radiation exposure to patients and to themselves. Through these good practices, technologists and radiologists minimize the possibility of causing damage to healthy biologic tissue. EFFECTIVE RADIATION PROTECTION Diagnostic imaging professionals have an ongoing responsibility to ensure radiation safety during all medical radiation procedures. They fulfill this obligation by adhering to an established radiation protection program. Radiation protection may be defined simply as effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation. This is any radiation exposure that does not benefit a person in terms of diagnostic information obtained for the clinical management of medical

3 CHAPTER 1 Introduction to Radiation Protection 3 Glass envelope X-ray beam (electromagnetic waves) Target (anode +) High-speed electron stream Filament (cathode ) FIGURE 1-1 Radiant energy is emitted from the x-ray tube in the form of waves (or particles). This manmade energy can be controlled by the selection of equipment components and devices made for this purpose and by the selection of appropriate technical exposure factors. needs or any radiation exposure that does not enhance the quality of the study. Effective protective measures take into consideration both human and environmental physical determinants, technical elements, and procedural factors. They consist of tools and techniques primarily designed to minimize radiation exposure while producing optimal-quality diagnostic images. To comprehend that process more fully, this textbook has been designed to introduce to its readers at appropriate times in the following chapters the relevant scientific principles that underlie those tools and techniques. In science, fundamental pieces of information are necessary to describe physical processes correctly. Some basic examples are the concepts of length, force, energy, and time. To know these concepts in a quantitative way, which is what scientific reality demands, units have been constructed to quantify every such concept uniquely. Unfortunately, there is not just one unique set or system of these units. Rather, three such unit systems are currently in existence, and each one has a significant area of usage. Appendix A contains detailed lists of all the major units comprising each of the three systems and furthermore gives the numeric relationships among the corresponding units of each system. Need to Safeguard against Significant and Continuing Radiation Exposure Biologic Effects. The need for safeguarding against significant and continuing radiation exposure is based on evidence of harmful biologic effects (i.e., damage to living tissue of animals and humans exposed to radiation). Various methods of radiation protection may be applied to ensure safety for persons employed in radiation industries, including medicine, and for the population at large. In medicine, when radiation safety principles are correctly applied during imaging procedures, the energy deposited in living tissue by the radiation can be limited, thereby reducing the potential for adverse biologic effects. This book focuses on radiation protection for patients, diagnostic imaging personnel, and the general public. Biologic effects are also discussed extensively in Chapters 7, 8, 9, and 10. JUSTIFICATION AND RESPONSIBILITY FOR IMAGING PROCEDURES Benefit versus Risk Radiation exposure should always be kept at the lowest possible level for the general public. However, when illness or injury occurs or when a specific imaging procedure for health screening purposes is prudent, a patient may elect to assume the relatively small risk of exposure to ionizing

4 4 CHAPTER 1 Introduction to Radiation Protection FIGURE 1-2 Mammography continues to be the most effective tool for diagnosing breast cancer. It can be used as a screening tool or a diagnostic procedure. In either instance, the directly realized benefit, in terms of medical information obtained, far outweighs any slight risk of possible biologic damage. radiation to obtain essential diagnostic medical information. A prime example of such a voluntary assumption of risk occurs when women elect to undergo screening mammography to detect breast cancer in its early stages ( Fig. 1-2 ). Because mammography continues to be the most effective tool for diagnosing breast cancer early, when the disease can best be treated, 1 its use contributes significantly to improving the quality of life for women. When ionizing radiation is used in this fashion for the welfare of the patient, the directly realized benefits of the exposure to this radiant energy far outweigh any slight risk of inducing a radiogenic malignancy or any genetic defects ( Fig. 1-3 ). Diagnostic Efficacy Diagnostic efficacy is the degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient. It is maximized when essential images are produced under recommended radiation protection guidelines. Potential benefits Potential risk of adverse biologic effects FIGURE 1-3 The potential benefits of exposing the patient to ionizing radiation must far outweigh the potential risk of adverse biologic effects. Efficacy is a vital part of radiation protection in the healing arts. It provides the basis for determining whether an imaging procedure or practice is justified ( Box 1-2 ). The referring physician carries the responsibility for determining this medical necessity for the patient. After ordering

5 CHAPTER 1 Introduction to Radiation Protection 5 BOX 1-2 Achievement of Diagnostic Efficacy Imaging procedure Minimal Optimal or practice justified radiation image() s by referring exposure produced physician Presence or absence Diagnostic = of disease efficacy revealed an x-ray examination or procedure, the referring physician must accept basic responsibility for protecting the patient from nonuseful radiation exposure. The physician exercises this responsibility by relying on qualified imaging personnel. As health care professionals, radiographers accept a portion of the responsibility for the patient s welfare by providing high-quality imaging services. The radiographer and participating radiologist share in keeping the patient s medical radiation exposure at the lowest level possible. In this way imaging professionals help ensure that both occupational and nonoccupational doses remain well below maximum allowable levels, that is, the upper boundary doses of ionizing radiation for which there is a negligible risk of bodily injury or genetic damage. This can best be accomplished by using the smallest radiation exposure that will produce useful images and by producing optimal images with the first exposure. Repeated examinations made necessary by technical error or carelessness ( Fig. 1-4 ) must be avoided because they significantly increase radiation exposure for both the patient and the radiation worker. AS LOW AS REASONABLY ACHIEVABLE (ALARA) PRINCIPLE Concepts of Radiologic Practice ALARA is an acronym for as low as reasonably achievable. This term is synonymous with the term optimization for radiation protection ( ORP ). The intention behind these concepts of radiologic practice is to keep radiation exposure and consequent dose to the lowest possible level ( Fig. 1-5 ). The rationale for this intention comes from evidence compiled by scientists over the past century. 2 At the time of this publication, radiation protection guidelines are rooted in the philosophy of ALARA. Therefore, this philosophy, as low as reasonably achievable, should be a main part of every health care facility s personnel radiation control program. In addition, because no dose limits have been established for the amount of radiation that patients may receive for individual imaging procedures, the ALARA philosophy should be established and maintained and must show that we have considered reasonable actions that will reduce doses to patients and personnel below required limits. Radiation-induced cancer does not have a fixed threshold, that is, a dose level below which individuals would have no chance of developing this disease. Therefore, because it appears that no safe dose levels exist for radiation-induced malignant disease, radiation exposure should always be kept ALARA for all medical imaging procedures, and ALARA should serve as a guide to radiographers and radiologists for the selection of technical exposure factors. For many radiation regulatory agencies (see Chapter 10 ), the ALARA principle provides a method for comparing the amount of radiation used in various health care facilities in a particular area for specific imaging procedures. An example using this method is provided in Box 1-3. Cardinal Rules of Radiation Protection The three basic principles of radiation protection are as follows: Time Distance Shielding

6 6 CHAPTER 1 Introduction to Radiation Protection A B C D FIGURE 1-4 A, Posteroanterior chest projection requiring repeat examination because of multiple external foreign bodies (several necklaces and an underwire bra) that should have been removed before the x-ray examination. B, Anteroposterior projection of a right hip requiring a repeat examination because of poor collimation and the presence of an external foreign body (a cigarette lighter) overlying the anatomy of concern. The patient s slacks with the pocket containing the lighter should have been removed before the x-ray examination. C, Double exposure (two lateral projections of the cervical spine) requiring a repeat examination. D, Conventional radiograph of left hip demonstrating an off-level grid error. This occurs when the patient s weight is not evenly distributed on the grid, thus causing the grid to tilt so that it is not properly aligned with the x-ray tube.

7 CHAPTER 1 Introduction to Radiation Protection 7 A FIGURE 1-5 A, Patient protection. B, Radiographer protection. Medical radiation exposure should always be kept as low as reasonably achievable (ALARA) for the patient and for imaging personnel. B BOX 1-3 Example of ALARA Method to Compare the Amount of Radiation That Various Health Care Facilities in a Particular Area Use for Specific Imaging Procedures If patients in a particular location were receiving on average approximately the same entrance skin exposure (ESE ) for a specific imaging procedure in every health care facility in that same area, then that ESE would represent the radiation exposure and consequent dose that is reasonably achieved within that specific location. However, if one of the health care facilities in this same area began giving its patients higher-radiation ESEs and subsequent doses, that institution would no longer be in compliance with ALARA (as low as reasonably achievable) standards. The noncompliant facility would have to take the necessary action to bring the ESE values and subsequent doses back to a level that would comply with regulatory standards. These principles can be applied to the patient and the radiographer. To reduce the exposure to the patient: Reduce the amount of the x-ray beam-on time. Use as much distance as warranted between the x-ray tube and the patient for the examination. Always shield the patient with appropriate gonadal and/or specific area shielding devices. Occupational radiation exposures of imaging personnel can be minimized by the use of these cardinal principles: Shortening the length of time spent in a room where x-radiation is produced Standing at the greatest distance possible from an energized x-ray beam Interposing a radiation-absorbent shielding material between the radiographer and the source of radiation These principles are discussed in greater detail in Chapter 13. Responsibility for Maintaining ALARA in the Medical Industry Both employers of radiation workers and the workers themselves have a responsibility for radiation safety in the medical industry. For the welfare of patients and the workers, facilities providing imaging services must have an effective

8 8 CHAPTER 1 Introduction to Radiation Protection radiation safety program. This requires a firm commitment to radiation safety by all participants. It is the responsibility of the employer to provide the necessary resources and appropriate environment in which to execute an ALARA program. A written policy statement describing this program and identifying the commitment of management to keeping all radiation exposure ALARA must be available to all employees in the workplace. In a hospital setting, an individual called the Radiation Safety Officer (RSO) is expressly charged by the hospital administration to be directly responsible for the Execution Enforcement Maintenance of the ALARA program. In Chapter 10, pp , the duties of the RSO are described in much more detail. To determine how radiation exposure in the workplace may be lowered, management should perform periodic exposure audits. 3 Radiation workers with appropriate education and work experience must function with awareness of rules governing the work situation. They are required to perform their occupational practices in a manner consistent with the ALARA principle ( Box 1-4 ). When radiation is safely and prudently used in the imaging of patients, the benefit of the exposure can be maximized while the potential risk of biologic damage is minimized. Additional information on the ALARA concept can be found in Chapter 10. PATIENT PROTECTION AND PATIENT EDUCATION Educating Patients about Imaging Procedures Facilities that provide imaging services have a responsibility to ensure the highest quality of service. An important aspect is education of patients about imaging procedures. Patients not only should be made aware of what a specific procedure involves and what type of cooperation BOX 1-4 Responsibilities for an Effective Radiation Safety Program Employers Responsibilities Implement and maintain an effective radiation safety program in which to execute ALARA * by providing the following: Necessary resources Appropriate environment for ALARA program Make a written policy statement describing the ALARA program and identifying the commitment of management to keep all radiation exposure ALARA available to all employees in the workplace. Perform periodic exposure audits to determine how to lower radiation exposure in the workplace. Radiation Workers Responsibilities Be aware of rules governing the workplace. Perform duties consistent with ALARA. *ALARA, As low as reasonably achievable. is required, but also they must be informed of what needs to be done, if anything, as a follow-up to their examination. Through appropriate and effective communication, patients can be made to feel that they are active participants in their own health care ( Fig. 1-6 ). Risk of Imaging Procedure versus Potential Benefit In general terms, risk can be defined as the probability of injury, ailment, or death resulting from an activity. In the medical industry with reference to the radiation sciences, risk is the possibility of inducing radiogenic cancer or a genetic defect after irradiation. Typically, people are more willing to accept a risk if they perceive that the potential benefit to be obtained is greater than the risk involved. Regarding exposure to ionizing radiation, patients who understand the medical benefit of an imaging procedure because they received factual information about the study before the examination are more likely to overcome any radiation phobia and be willing to assume a small risk of possible biologic damage. Greater understanding of biologic effects

9 CHAPTER 1 Introduction to Radiation Protection 9 FIGURE 1-6 Effective communication is an important part of the patient-radiographer relationship. Patients need to be educated about imaging procedures so that they can understand what the procedure involves and what type of cooperation is required. The radiographer must answer patient questions about the potential risk of radiation exposure honestly. To create understanding and reduce fear and anxiety for the patient, the radiographer can provide an example that compares the amount of radiation received for a specific procedure with natural background radiation received over a given period of time. associated with diagnostic radiology was gained throughout the twentieth century. The medical imaging industry currently continues to build on this knowledge. This information, coupled with better design of medical imaging equipment and improved radiation safety standards, has greatly reduced risk from imaging procedures for both patients and radiographers. When radiographers use their intelligence and knowledge to answer patients questions about the risk of radiation exposure honestly, they can do much to alleviate patients apprehension and fears during a routine radiologic examination. Background Equivalent Radiation Time Another way that radiographers can improve understanding and reduce fear and anxiety for the patient is to use the background equivalent radiation time ( BERT ) method. On occasion, a patient will ask the radiographer, Are x-rays safe? Radiologic technologists have a responsibility to give a reasonable, honest, and understandable answer to the patient. Radiographers correctly tell patients that for normal diagnostic examinations there are no existing data of any unsafe effects from the x-rays used in the ex - amination. The question about the amount of radiation to the patient is difficult to answer in an understandable way because (1) the received dose is measured in a number of different units and (2) scientific units for radiation dose are not comprehensible by the patient. The purpose is not to provide high scientific accuracy but to relieve anxiety about radiation by giving an understandable and reasonable correct answer. The BERT method compares the amount of radiation received, for example, from a patient s chest x-ray examination or from radiography of any other part of the anatomy, with natural background radiation received over a specified period of time such as days, weeks, months, or years ( Table 1-1 ). This method is also recommended by the U.S. National Council on Radiation Protection and Measurements (NCRP). 4 For example, a patient is having a chest x-ray study and asks the radiographer, How much radiation will I receive from this x-ray? The radiographer can respond by using an estimation based on the comparison of radiation received from the x-ray to natural background radiation received, for example, over a certain number of days. Thus the radiographer can reply, The radiation received from having a chest x-ray is equivalent to what would be received while spending approximately 10 days in your natural surroundings (see Table 1-1 ). BERT is based on an annual U.S. population exposure of approximately 3 millisieverts per year. * Using the BERT method in this context has the following advantages: BERT does not imply radiation risk; it is simply a means for comparison. BERT emphasizes that radiation is an innate part of our environment. The answer given in terms of BERT is easy for the patient to comprehend. * The millisievert ( msv ), a subunit of the sievert (Sv), is equal to of a sievert. The sievert ( Sv ) is the International System of Units (SI) unit of measure for the radiation quantity equivalent dose.

10 10 CHAPTER 1 Introduction to Radiation Protection TABLE 1-1 Typical Adult Patient Effective Dose (EfD) and Background Equivalent Radiation Time (BERT) Values Radiologic Procedure EfD (msv) Dental, intraoral wk Chest radiograph days Cervical spine wk Thoracic spine mo Lumbar spine yr Upper GI series yr Lower GI series yr Skull day Hip wk Pelvis mo Abdomen mo Limbs and joints (except hip) <0.01 <1.5 days CT brain yr CT chest yr CT abdomen/pelvis yr BERT (Amount of Time to Receive the Same EfD from Nature) Adapted from BF Wall: Patient dosimetry techniques in diagnostic radiology, York, UK, 1988, Institute of Physics and Engineering in Medicine, pp 53, 117; Cameron JR: Med Phys World, 15:20, 1999; Stabin MG: Radiation protection and dosimetry: an introduction to health physics, New York, 2008, Springer. CT, Computed tomography; GI, gastrointestinal; msv, millisievert. Patients may mistakenly think that manmade radiation is more dangerous than an equal amount of natural radiation. Most patients are unaware that most of their background radiation comes from natural radioactivity in their own body. Radiation phobia can be greatly reduced by explaining the diagnostic radiation dose to the patient by using the BERT method. Radiologic technologists have a responsibility to educate patients and others who ask them about radiation. The BERT concept is understandable. BERT is not a radiation quantity. It is a method of explaining radiation to the public. The word BERT is never used in the explanation. 5 Tools for Radiation Awareness and Community Education (TRACE) Program In 2010 Toshiba American Medical Systems awarded six Putting Patients First Grants to individual hospitals throughout the United States to create a radiation dose awareness and dose reduction program for patients through the process of education for these individuals, for the community, for health care workers employed in the medical imaging profession, and for physicians. 6,7 The main components of the program include technologic enhancements such as embedded software capable of recording and reporting dose, timely notification of the patient and the referring physician when the radiation dose is greater than 3 Gy, and substantial lowering of computed tomography (CT) doses through improved technology and alterations to existing protocols. 7 This process is known as the Tools for Radiation Awareness and Community Education (TRACE) Program. It consists of two phases: 1. Formulating new policies and procedures to promote radiation safety and the implementation of patient and community education 2. Technologic enhancements

11 CHAPTER 1 Introduction to Radiation Protection 11 During phase one of the TRACE Program, after new and more definitive radiation safety policies and procedures have been written, some ways of providing patient and community education are through the use of: 1. Informational posters placed strategically throughout the health care facility. 2. Brochures that describe imaging procedures in simple terms. 3. Basic information on a specific website designed for patient education. 4. Use of a wallet-size card on which a person s radiation exposure can be recorded and tracked. Some ways of providing education for imaging department staff are: 1. Providing in-service education on various radiation safety topics to accommodate individual needs of staff members. 2. Handing out a facts-to-remember sheet at the end of an in-service program. 3. s highlighting the most important topics covered in a staff in-service program to imaging staff members to help reinforce and retain vital information. Some ways of providing education for nonradiologist physicians who perform fluoroscopic procedures can include: 1. Creating increased awareness of radiation dose for specific procedures through discussion. 2. Establishing goals for lowering radiation dose for patients, assisting personnel, and themselves. 3. Radiographers helping physicians performing fluoroscopic procedures by informing them that they have reached a specific dose, 7 thereby giving fluoroscopists the opportunity to decide to continue or stop a procedure. During phase two of the TRACE Program, to accommodate technologic enhancements, the following items are required: 1. An operational or capital budget, such as acquiring CT dose reduction technology 7 2. Utilization of tools for recording and reporting dose 7 3. Providing notification for excessive radiation dose 7 Introducing and implementing the TRACE Program in a medical imaging department can lead to greater radiation safety through patient and community education. Patients become empowered and benefit through their inclusion in decisions concerning their own radiologic care. Physicians become better able to make decisions involving the use of ionizing radiation because the TRACE Program creates greater awareness of radiation doses. 6 The end result of this program is a reduction in dose to the patient. Standardized Dose Reporting Standardization of dose reporting can also lead to a reduction in radiation dose for patients. A large variability in radiation dose still exists for many procedures. The radiation dose to the patient for individual procedures, such as those involving general fluoroscopy, CT, and interventional procedures, needs to be dictated into every radiologic report. Many newer CT systems and interventional fluoroscopic units possess the technical capability for standardized dose structured reporting. 8 However, other ionizing radiation equipment may not as yet have such a capability. The benefit to the referring physician in having direct access to a patient s radiation dose history is the option of knowing whether ordering an additional radiologic procedure is advisable. The need to develop a way for each radiationproducing modality to record a patient s radiation dose persists. SUMMARY Ionizing radiation has both a beneficial and a destructive potential. Healthy normal biologic tissue can be injured by ionizing radiation; therefore, it is

12 12 CHAPTER 1 Introduction to Radiation Protection necessary to protect humans against significant and continuous exposure. X-rays are a form of ionizing radiation; therefore, their use in medicine for the detection of disease and injury requires protective measures. To safeguard patients, personnel, and the general public, effective radiation protection measures should always be employed when diagnostic imaging procedures are performed. Radiation exposure should always be kept as low as reasonably achievable (ALARA) to minimize the probability of any potential damage to people. Referring physicians should justify the need for every radiation procedure and accept basic responsibility to protect the patient from excessive ionizing radiation. The benefits of exposing patients to ionizing radiation should far outweigh any slight risk of inducing radiogenic cancer or genetic effects after irradiation. Radiographers should select the smallest radiation exposure that produces the best radiographic results and should avoid errors that result in repeated radiographic exposures. Imaging facilities must have an effective radiation safety program that provides patient protection and patient education. Background equivalent radiation time (BERT) is used to compare the amount of radiation a patient receives from a radiologic procedure with natural background radiation received over a specific period of time. The millisievert (msv) is equal to of a sievert (Sv). The Tools for Radiation Awareness and Community Education (TRACE) Program helps patients and the community to enhance understanding for using radiation safely and for enabling these people to participate in their own medical decisions more actively. Methods for standardized patient radiation dose reporting must be developed and implemented. REFERENCES 1. Women s breast health: annual reminder needed for mammography. RT Image 17 : 35, National Research Council, Commission of Life Sciences, Committee on Biological Effects on Ionizing Radiation (BEIR V), Board on Radiation Effects Research : Health effects of exposure to low levels of ionizing radiations, Washington, DC, 1989, National Academy Press. 3. Gollnick DA : Basic radiation protection technology, ed 4, Altadena, Calif, 2000, Pacific Radiation Corporation. 4. National Council on Radiation Protection and Measurements (NCRP) : Research needs for radiation protection, Report No Bethesda, MD, 1993, NCRP, p Ng K-H, Cameron JR: Using the BERT concept to promote understanding of radiation, International conference on the radiological protection of patients organized by the International Atomic Energy Agency, Malaga, Spain, March C&S Paper Series 7/P, Austria, Vienna Radiation Safety Awareness. Available at : healthoutlook.com/summer-2011/106-radiation-safety -awareness. Accessed September 8, Rinehart B : TRACE Program: improving patient safety. Radiol Manage 33 : 35, Center for Devices and Radiological Health, U.S. Food and Drug Administration: White Paper: initiative to reduce unnecessary radiation exposure from medical imaging, Washington, DC, U.S. Government Printing Office, February GENERAL DISCUSSION QUESTIONS 1. What are the consequences of ionization in the human cell? 2. When is medical radiation exposure considered unnecessary? 3. How can the background equivalent radiation time (BERT) method be used to eliminate a patient s fears about medical radiation exposure? 4. Describe how radiographers can use the ALARA concept in the performance of their daily responsibilities. 5. How does implementation of the TRACE Program improve patient safety? 6. How will a patient benefit from standardized radiation dose reporting?

13 CHAPTER 1 Introduction to Radiation Protection Why should the ALARA philosophy be established and maintained as a main part of every health care facility s radiation safety program? 8. When are patients more likely to overcome any radiation phobia and be willing to assume a small risk of possible biologic damage? 9. On what premise is BERT based? 10. In the medical industry with reference to the radiation sciences, how is risk defined? REVIEW QUESTIONS 1. A patient may elect to assume the relatively small risk of exposure to ionizing radiation to obtain essential diagnostic medical information when: 1. Illness occurs 2. Injury occurs 3. A specific imaging procedure for health screening purposes is prudent A. 1 and 2 only B. 1 and 3 only C. 2 and 3 only D. 1, 2, and 3 2. Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation define: A. Diagnostic efficacy. B. Optimization. C. Radiation protection. D. The concept of equivalent dose (EqD). 3. Which of the following is a method that can be used to answer patients questions about the amount of radiation received from a radiographic procedure? A. ALARA concept B. BERT C. BRET D. EPA 4. The term optimization for radiation protection (ORP) is synonymous with the term: A. As low as reasonably achievable (ALARA). B. Background equivalent radiation time (BERT). C. Equivalent dose (EqD). D. Diagnostic efficacy (DE). 5. Standardized dose reporting for radiologic procedures can lead to: A. An invasion of patient privacy. B. An increase in patient radiation dose. C. A reduction in patient radiation dose. D. Elimination of the need for imaging equipment radiation safety features. 6. Which of the following is a two-phase program to create radiation awareness and community education? A. ALARA B. BERT C. DE D. TRACE 7. The degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient defines which of the following terms? A. Radiation protection B. Radiographic pathology C. Effective diagnosis D. Diagnostic efficacy 8. The millisievert (msv) is equal to: A of a sievert. B of a sievert. C of a sievert. D. 1 10, 000 of a sievert. 9. An effective radiation safety program requires a firm commitment to radiation safety by: 1. Facilities providing imaging services 2. Radiation workers 3. Patients A. 1 and 2 only B. 1 and 3 only C. 2 and 3 only D. 1, 2, and 3

14 14 CHAPTER 1 Introduction to Radiation Protection 10. If patients in facilities in the same location are receiving on average approximately the same entrance skin exposure (ESE) in every health care facility for a specific imaging procedure with the exception of one facility, in which higher-radiation ESEs and subsequent doses are being received for the same procedure, that institution would: A. Be excluded from the group of compliant facilities for comparison purposes. B. No longer be in compliance with ALARA standards and would have to take the necessary action to bring the ESE values and subsequent doses back to a level that would comply with regulatory standards. C. Simply establish their own ESE values for the specific procedure in question and ignore ALARA standards. D. Be required to close down the facility immediately.