ANNEX D Medical Radiation Exposures
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ANNEX D Medical radiation exposures CONTENTS Page INTRODUCTION................................................... 295 I. SCOPE AND BASIS FOR THE ANALYSIS .......................... 295 A. MEDICALRADIATIONPROCEDURES........................ 295 B. SOURCESOFDATA ....................................... 296 C. DOSIMETRICASPECTS .................................... 296 D. ASSESSMENTOFGLOBALPRACTICE........................ 297 E. SUMMARY............................................... 297 II. DIAGNOSTIC RADIOLOGY ..................................... 300 A. TECHNIQUESOFEXAMINATION............................ 300 B. DOSIMETRY ............................................. 300 C. ANALYSIS OF EXPOSURES ................................. 302 1. Frequencyofexaminations ............................... 302 2. Exposedpopulations .................................... 302 3. Dosesfromspecifictypesofexamination..................... 303 D. ASSESSMENTOFGLOBALPRACTICE........................ 309 E. TRENDS IN DIAGNOSTIC RADIOLOGY ....................... 309 1. Frequenciesofexaminations .............................. 310 2. Dosesperexamination................................... 312 3. Quality assurance and patient protection initiatives ............. 313 F. SUMMARY............................................... 314 III. DIAGNOSTIC ADMINISTRATIONS OF RADIOPHARMACEUTICALS . 315 A. TECHNIQUES............................................. 315 B. DOSIMETRY ............................................. 316 C. ANALYSIS OF EXPOSURES ................................. 316 1. Frequencyofexaminations ............................... 316 2. Exposedpopulations .................................... 317 3. Doses................................................ 317 D. ASSESSMENTOFGLOBALPRACTICE........................ 318 E. TRENDS IN DIAGNOSTIC PRACTICE WITH RADIOPHARMACEUTICALS................................ 318 1. Frequenciesofexaminations .............................. 318 2. Diagnosticpractices..................................... 319 F. SUMMARY............................................... 320 294 ANNEX D: MEDICAL RADIATION EXPOSURES Page IV. TELETHERAPYANDBRACHYTHERAPY.......................... 320 A. TECHNIQUES............................................. 321 B. DOSIMETRY ............................................. 321 C. ANALYSIS OF EXPOSURES ................................. 322 1. Frequencyoftreatments.................................. 322 2. Exposedpopulations .................................... 323 3. Dosesfromtreatments................................... 323 D. ASSESSMENTOFGLOBALPRACTICE........................ 324 E. TRENDSINTELETHERAPYANDBRACHYTHERAPY........... 325 1. Frequenciesoftreatments ................................ 325 2. Therapeuticpractices.................................... 325 F. SUMMARY............................................... 328 V. THERAPEUTIC ADMINISTRATIONS OF RADIOPHARMACEUTICALS . 328 A. TECHNIQUES............................................. 328 B. DOSIMETRY ............................................. 329 C. ANALYSIS OF EXPOSURES ................................. 329 1. Frequencyoftreatments.................................. 329 2. Exposedpopulations .................................... 330 3. Dosesfromtreatments................................... 330 D. ASSESSMENTOFGLOBALPRACTICE........................ 330 E. TRENDSINTHERAPYWITHRADIOPHARMACEUTICALS....... 330 1. Frequenciesoftreatment ................................. 330 2. Therapeuticpractices.................................... 331 F. SUMMARY............................................... 331 VI. EXPOSURES OF VOLUNTEERS IN MEDICAL RESEARCH ............ 332 VII.ACCIDENTALEXPOSURESOFPATIENTS......................... 332 CONCLUSIONS.................................................... 333 Tables ............................................................ 336 References ......................................................... 467 ANNEX D: MEDICAL RADIATION EXPOSURES 295 INTRODUCTION 1. Over the last 100 years, ionizing radiation has been in countries where medical services are in the earlier stages of increasingly applied in medicine and is now firmly estab- development [U3]. However, further and more lished as an essential tool for diagnosis and therapy. The comprehensive analyses would be required in order to refine overwhelming benefits accruing to patients from properly global estimates and establish important trends. conducted procedures have fostered the widespread practice of medical radiology [A22], with the result that medical 4. The need for such analysis is heightened bya number of radiation exposures have become an important component of underlying factors that could affect the practice of radiology, the total radiation exposure of populations. in terms of both the type and frequency of procedures carried out and the associated levels of dose to individual patients 2. Since beginning its work in 1955, the Committee has [S60]. For example, population growth, urbanization, and regularly monitored the medical uses of radiation as part of its longer lifespans can be expected to result in growing demands continuing review of sources of exposure. The most recent for medical radiology [U3]. Conversely, as a general trend analysis, included in the UNSCEAR 1993 Report [U3], some reductions in dose can be expected to arise from covered theperiod 19851990, but information available since continuing advances in the technology for ionizing radiation 1970 was cited in order to investigate trends in usage and and its substitution by non-ionizing radiations, more doses. TheCommitteeconcluded that medical applicationsare widespread and formalized implementation of quality the largest man-made source of radiation exposure for the assuranceproceduresin radiologydepartments, better training world’s population, although there was still a far from of staff involved in medical radiology [I2], and more rigorous equitable distribution of medical radiation services in different standards for patient protection [I3, I5, I17]. countries with different levels of health care; whereas the 1993 worldwide estimate for the annual per caput dose from 5. Accordingly, this Annex presents the results of an diagnostic examinations was 0.3 mSv, corresponding average updated, broad review of medical radiation exposures. Its values for countries of the upper and lower health-care levels purpose is to provide new qualitative and quantitative were 1.1 mSv and 0.05 mSv, respectively. A century after information on the frequencies and doses for diagnostic Röntgen's seminal discovery of x rays, some two thirds of the and therapeutic procedures, to assess medical radiation world'spopulation still lacks adequate diagnostic imaging and exposures worldwide, to make comparisons with data from radiation therapy services [W12]. previous reviews, and to explore temporal or regional trends in the practice of medical radiology. Although the 3. The Committee also concluded that population expo- review is not intended as a means to optimize procedures sures from the diagnostic and therapeutic uses of ionizing or as a guideline for radiation protection, it will never- radiation were likely to be increasing worldwide, particularly theless provide the background for such work. I. SCOPE AND BASIS FOR THE ANALYSIS A. MEDICAL RADIATION PROCEDURES unsealed radio-nuclides, the disposal of radioactive waste from hospitals, and the production of radionuclides for 6. This Annex is principally concerned with exposures medicine are considered in Annex C, “Exposures to the received by patients from the use of radiation generators or public from man-made sources of radiation”. radionuclides as part of their diagnosis or treatment (Chapters IIV). Medical exposures are also conducted for medico-legal 7. Diagnostic procedures, in particular the widespread use reasons and on volunteers (patients or healthy persons) for the of x rays, are the most common application of radiation in purposes of research; this latter category of exposures is medicine. The range of x-ray techniques used, such as considered in Chapter VI. The information on patient radiography, fluoroscopy, computed tomography, exposures reported for different types of procedure in various interventional radiology, and bone densitometry, arediscussed countries is assumed to reflect routine practice, although a in Chapter II. There is also significant practice in imaging and brief discussion of radiation incidents in medicine is included other functional studies involving administrations to patients in Chapter VII for the purpose of illustration. Exposures of unsealed radionuclides; these uses are described in Chapter received by medical staff from medical radiology are III. Such nuclear medicine and x-ray procedures are intended discussed elsewhere, in Annex E, “Occupational radiation toprovidedoctorswith diagnosticinformation and in principle exposures”. Exposures of the general public arising from are conducted with the lowest practicable levels of patient dose contact with patients undergoing therapy with sealed or to meet clinical objectives [M39, S54]. 296 ANNEX D: MEDICAL RADIATION EXPOSURES 8. In contrast, therapeutic exposures are less frequent and instances of extrapolation are generally identified in the the levels of dose are very much higher in view of the quite footnotes to the tables. The interpretation of non-standard different purpose. Radiotherapy is used mainly for the or incomplete dosimetric information provided in the treatment of cancer, where