The U.S. National Council on Radiation Protection and Measurements (NCRP) conducted a retrospective assessment of the U.S. data, and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) performed a similar worldwide assessment for 2009-2018 (with most data from 2014 to 2017). Using the data from those reports, the frequency of radiologic and nuclear medicine studies, annual collective, and per capita effective dose in the United States for 2016 were compared with worldwide estimates from 2009 to 2018. There were an estimated 691 million radiologic, CT, dental, and nuclear medicine studies performed in the United States in 2016, which represented 16.5% of the 4.2 billion performed worldwide. The United States also accounted for 74 million CT procedures (18% of the world's estimated total), 275 million conventional radiology procedures (11% of the world's total), 8.1 million interventional radiologic procedures (34% of the world's total), 320 million dental radiography procedures (29% of the world's total), and 13.5 million nuclear medicine procedures (34% of the world's total). The U.S. collective effective dose was 717 000 person-sieverts (17.6% of the world's total). The average annual individual effective dose in the United States was 2.2 mSv compared with 0.56 mSv worldwide. The United States accounts for a large and disproportionate share of global medical radiation procedures and collective effective dose, but use of CT has increased more in other countries compared with the United States.

This a historical review and current information regarding risks and effects of ionizing radiation in the context of human pregnancy and in particular the information needed for pregnant women to understand the type and magnitude of risks placing them in a realistic context. Much of our understanding comes from early animal studies but has been supported by studies of human exposure to medical radiation, radiation accidents and nuclear weapons.

HomeRadiologyVol. 300, No. 3 PreviousNext Reviews and CommentaryFree AccessEditorialOccupational Exposure in General Radiology and Nuclear Medicine: A Changing TargetFred A. Mettler, Jr , Milton J. GuiberteauFred A. Mettler, Jr , Milton J. GuiberteauAuthor AffiliationsFrom the Department of Radiology, University of New Mexico School of Medicine, 2211 Lomas Blvd NE, Albuquerque, NM 87106 (F.A.M.); and 619 Northumberland Rd, Austin, Tex (M.J.G.).Address correspondence to F.A.M. (e-mail: [email protected]).Fred A. Mettler, Jr Milton J. GuiberteauPublished Online:Jun 22 2021https://doi.org/10.1148/radiol.2021211104MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In See also the article by Villoing et al in this issue.Dr Mettler is an emeritus professor in the Department of Radiology at the University of New Mexico. His research interests include radiation dose, radiation effects on humans, and radiation injury. He is an emeritus commissioner of the International Commission on Radiological Protection and an emeritus member of the National Council on Radiation Protection and Measurements.Download as PowerPointOpen in Image Viewer Dr Guiberteau is a former professor of diagnostic radiology at Baylor College of Medicine, with 40 years of experience in diagnostic radiology and nuclear medicine. He has served as president of the American College of Radiology, chair of the ACR Commission on Nuclear Medicine, and president of the American Board of Radiology, and he is a member of the National Council on Radiation Protection and Measurements.Download as PowerPointOpen in Image Viewer Physicians, technologists, and nurses comprise the largest group of workers exposed to manmade radiation. Reduction in occupational radiation exposure in medicine has been a matter of intense interest since 1896, when only 1 month after the discovery of x-rays, Herman Grubbé experience x-ray burns and dermatitis. Fortunately, over the next 125 years, most occupational doses in medicine have declined significantly because of improved radiation protection practices, even as challenges brought by new technologies and procedures have arisen (1,2). These challenges have included the emergence of increasing volumes of higher per-procedure doses in nuclear medicine (NM), especially in PET imaging and cardiac studies, and new complex interventional radiology procedures performed under often lengthy fluoroscopic control. In this issue of Radiology, Villoing et al (3) use personal dosimetry data to document and quantify rising NM technologist doses even as doses in general diagnostic radiology have declined.The largest amount of historic data regarding U.S. radiologic technologist doses comes from the U.S. Radiologic Technologists cohort, which was initially developed by Boice et al (4) with the idea to search for health effects from chronic low (<100 mSv) doses. Initially, more than 146 000 individuals were identified and surveyed from the 1926–1982 certification files of the American Registry of Radiologic Technologists. These self-reported health effects include cancer, cardiovascular disease, and cataracts over varying time periods and are associated with different self-reported work habits. Because the study is ongoing, there have been four periodic questionnaire surveys between 1983 and 2014. In their study, Villoing et al (3) make use of the results of the most recent survey respondents (years 2012–2014) comprising 58 434 technologists. They analyzed badge readings (personal dose equivalent) from 1980 to 2015 normalized by Landauer for different detector technologies used over time. In nearly all publications to date, the use of self-reported work history as a surrogate for dose has been an investigational weakness, although innovative statistical methods have been used to overcome this (5). The addition of this historical badge dose data combined with knowledge of work habits from the surveys in this investigation is an important step forward in collecting objective data, and in this case, it renders valuable and illuminating information about the levels and trends in occupational doses. It also allows division of the respondents into subsets of technologists, most notably those performing general radiologic procedures (without NM or fluoroscopically guided interventional procedures) and NM technologists (with and without PET or cardiac imaging), as well as several other groupings.The study is complex and detailed. Radiologists are likely to be most interested in the more recent data. For general radiologic technologists not performing fluoroscopically guided interventional or NM procedures, the annual doses were very low. Median annual doses related to performance of general radiologic procedures decreased from 0.60 mSv in 1980 to levels below the limits of detection by 2015. For technologists regularly performing NM procedures, the median annual personal dose equivalent from 1980 to 2015 was 1.2 mSv (interquartile range [IQR], 0.12–3.0 mSv). Higher and more variable annual doses were associated with more frequent performance of cardiac NM (≥10 times per week) and PET (≥9 times per week), with median doses of 1.6 mSv (IQR = 0.30–2.2 mSv) and 2.2 mSv (IQR = 0.10–4.6 mSv), respectively. Of note, for the PET annual doses, there were some with an upper range of 6–12 mSv. Higher doses were observed for regular performance of diagnostic but not therapeutic NM procedures compared with therapeutic but not diagnostic NM procedures (median, 0.90 mSv [IQR, minimal to 2.8 mSv] and 0.21 mSv [IQR, minimal to 1.4 mSv], respectively).What are we to take away from all this? First, the occupational doses to most general radiologic and NM technologists are in the low-dose range (<100 mSv). However, we should remain cognizant that for epidemiologic assessment of future health risk at these dose levels, more powerful statistical data are needed. Given the number of technologists and their low occupational doses, going forward the statistical power will remain below that of the atomic bomb survivor studies (6,7) and the large multinational studies of nuclear workers (8). Even though annual doses are higher in NM technologists who perform cardiac and PET procedures, the even lower number of personnel seems unlikely to generate adequately robust data. On the other hand, the data from the U.S. Radiologic Technologists might be combined with other cohorts in the so-called million-person study to increase statistical power to adequate levels (9).Second, there is good news. Radiation protection is working. Who would have guessed that from 1980 to 2015 radiologic technologists had median annual occupational doses of 0.05 mSv and that after 2008 about half were below the limit of detection (0.01 mSv)? This does not mean we should ignore such doses or become complacent. “As low as reasonably achievable” remains a cornerstone of radiation protection, and programs like Image Gently and Image Wisely continue to be important.Finally, if not ideal, the type of data presented by Villoing et al (3) are certainly valuable in determining trends in occupational doses among NM and general diagnostic radiologic technologists. This information can be used to direct us in our current and future radiation protection efforts. Clearly, we know that complex interventional procedures will require continued attention for a long time to come to prevent patient radiation injuries and limit operator doses. What may come as a bit of a surprise to many, is that a number of institutions have realized, and the current data show, that doses associated with PET procedures result in the need to pay very careful attention, as novel radiopharmaceuticals lead to even higher volumes. This caution must necessarily extend beyond the traditional occupational realm to the issue of the pregnant technologist. Given that the Nuclear Regulatory Commission requires licensees to ensure that the dose equivalent to the embryo or fetus from the occupational exposure of a declared pregnant woman does not exceed 0.5 rem (5 mSv). Given the now documented rising doses to technologists performing PET, we must be especially alert.Disclosures of Conflicts of Interest: M.J.G. disclosed no relevant relationships. F.A.M. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: provided expert testimony at labor board hearing for Drummond and Mallinckrodt Chemical; receives royalties from Elsevier. Other relationships: disclosed no relevant relationships.References1. Boice J Jr, Dauer LT, Kase KR, Mettler FA Jr, Vetter RJ. Evolution of radiation protection for medical workers. Br J Radiol 2020;93(1112):20200282. Crossref, Medline, Google Scholar2. National Council on Radiation Protection and Measurements. Medical radiation exposure of patients in the United States. NCRP Report 184.Bethesda, Md:National Council on Radiation Protection and Measurements,2019. Google Scholar3. Villoing D, Borrego D, Preston DL, et al. Trends in occupational radiation doses for U.S. radiologic technologists performing general radiologic and nuclear medicine procedures, 1980-2015. Radiology 2021.https://doi.org/10.1148/radiol.2021204501. Published online June 22, 2021. Link, Google Scholar4. Boice JD Jr, Mandel JS, Doody MM, Yoder RC, McGowan R. A health survey of radiologic technologists. Cancer 1992;69(2):586–598. Crossref, Medline, Google Scholar5. Simon SL, Weinstock RM, Doody MM, et al. Estimating historical radiation doses to a cohort of U.S. radiologic technologists. Radiat Res 2006;166(1 Pt 2):174–192. Crossref, Medline, Google Scholar6. Grant EJ, Brenner A, Sugiyama H, et al. Solid Cancer Incidence among the Life Span Study of Atomic Bomb Survivors: 1958-2009. Radiat Res 2017;187(5):513–537. Crossref, Medline, Google Scholar7. Ozasa K, Shimizu Y, Suyama A, et al. Studies of the mortality of atomic bomb survivors, Report 14, 1950-2003: an overview of cancer and noncancer diseases. Radiat Res 2012;177(3):229–243. Crossref, Medline, Google Scholar8. Richardson DB, Cardis E, Daniels RD, et al. Site-specific Solid Cancer Mortality After Exposure to Ionizing Radiation: A Cohort Study of Workers (INWORKS). Epidemiology 2018;29(1):31–40. Crossref, Medline, Google Scholar9. Boice JD Jr, Cohen SS, Mumma MT, Ellis ED. The Million Person Study, whence it came and why. Int J Radiat Biol 20191–14. Google ScholarArticle HistoryReceived: Apr 29 2021Revision requested: May 10 2021Revision received: May 24 2021Accepted: May 27 2021Published online: June 22 2021Published in print: Sept 2021 FiguresReferencesRelatedDetailsAccompanying This ArticleTrends in Occupational Radiation Doses for U.S. Radiologic Technologists Performing General Radiologic and Nuclear Medicine Procedures, 1980–2015Jun 22 2021RadiologyRecommended Articles Cataract Risk in a Cohort of U.S. Radiologic Technologists Performing Nuclear Medicine ProceduresRadiology2017Volume: 286Issue: 2pp. 592-601A U.S. Multicenter Study of Recorded Occupational Radiation Badge Doses in Nuclear MedicineRadiology2018Volume: 287Issue: 2pp. 676-682Reawakening of Nuclear Medicine through Molecular Imaging: Quantitative Theranostics and PSMA PETRadiology2023Volume: 307Issue: 4Trends in Occupational Radiation Doses for U.S. Radiologic Technologists Performing General Radiologic and Nuclear Medicine Procedures, 1980–2015Radiology2021Volume: 300Issue: 3pp. 605-612Medical Radiation Exposure to the U.S. Population: The Turning TideRadiology2020Volume: 295Issue: 2pp. 428-429See More RSNA Education Exhibits Radioisotope Safety Exam: What Every Radiology Resident Needs to Know to Pass the ExamDigital Posters2019Radiation Exposure in Pregnancy: It’s Hot in Here!Digital Posters2019How We Do It: A Multidisciplinary Approach to Lu- 177 Dotatate PRRT (Peptide Receptor Radionuclide Therapy)Digital Posters2019 RSNA Case Collection Cardiac AmyloidosisRSNA Case Collection2020Postradiation sacral insufficiency fractureRSNA Case Collection2021Primary Bone LymphomaRSNA Case Collection2020 Vol. 300, No. 3 Metrics Altmetric Score PDF download

Background Comprehensive assessments of the frequency and associated doses from radiologic and nuclear medicine procedures are rarely conducted. The use of these procedures and the population-based radiation dose increased remarkably from 1980 to 2006. Purpose To determine the change in per capita radiation exposure in the United States from 2006 to 2016. Materials and Methods The U.S. National Council on Radiation Protection and Measurements conducted a retrospective assessment for 2016 and compared the results to previously published data for the year 2006. Effective dose values for procedures were obtained from the literature, and frequency data were obtained from commercial, governmental, and professional society data. Results In the United States in 2006, an estimated 377 million diagnostic and interventional radiologic examinations were performed. This value remained essentially the same for 2016 even though the U.S. population had increased by about 24 million people. The number of CT scans performed increased from 67 million to 84 million, but the number of other procedures (eg, diagnostic fluoroscopy) and nuclear medicine procedures decreased from 17 million to 13.5 million. The number of dental radiographic and dental CT examinations performed was estimated to be about 320 million in 2016. Using the tissue-weighting factors from Publication 60 of the International Commission on Radiological Protection, the U.S. annual individual (per capita) effective dose from diagnostic and interventional medical procedures was estimated to have been 2.9 mSv in 2006 and 2.3 mSv in 2016, with the collective doses being 885 000 and 755 000 person-sievert, respectively. Conclusion The trend from 1980 to 2006 of increasing dose from medical radiation has reversed. Estimated 2016 total collective effective dose and radiation dose per capita dose are lower than in 2006. © RSNA, 2020 See also the editorial by Einstein in this issue.

The National Council on Radiation Protection and Measurements (NCRP) recently assessed patient radiation exposure in the United States, which was summarized in its 2019 NCRP Report No. 184. This work involved an estimation of the number of medical procedures using ionizing radiation, as well as the associated effective doses from these procedures. The NCRP Report No. 184 committee elected to not incorporate radiation dose from radiotherapy into its calculated population dose exposures, as the assessment of effective dose for the population undergoing radiotherapy is more complex than that for other medical radiation exposures. However, the aim of NCRP Report No. 184 was to raise awareness of ancillary radiation exposures to patients undergoing radiotherapy. Overall, it was estimated that annually, in 2016, approximately 800,000 patients received approximately 1 million courses of radiation therapy. Each of these treatments includes various types of imaging that may not be familiar to radiologists or others. Exposures from radiotherapy planning and delivery are reviewed in the report and summarized in this executive summary. The imaging techniques, use of this imaging, and associated tissue doses are described. Imaging can contribute a few percent to the planned treatment doses (which are prescribed to specified target volumes) as well as exposing patients to radiation outside of the target volume (in the imaging field of view).

The National Council on Radiation Protection and Measurements (NCRP) held its 55 Annual Meeting 1-2 April 2019 in Bethesda, Maryland. The 2019 meeting was a special year for NCRP as it marked the 90 Anniversary of the founding of the predecessor organization, US Advisory Committee on X-Ray and Radium Protection. Leaders for the scientific portion of the meeting were Fred A. Mettler, Jr., M.D. (Chair), University of New Mexico School of Medicine; Jerrold T. Bushberg, Ph.D. (Co-Chair), University of California Davis; and Richard J. Vetter, Ph.D. (Co-Chair), Mayo Clinic. The meeting was designed to explore important areas of inquiry associated with use of ionizing radiation relevant to radiation protection, addressing frequently asked questions and concerns from both members of the public and radiation professionals. The meeting was organized into six sessions plus three honorary lectures and a special presentation. This paper summarizes the scientific content of the six sessions and is based on the notes of the co-chairs and the slides of the speakers. The three honorary lectures are included as other papers in this issue.

Within a few months of discovery, x-rays were being used worldwide for diagnosis and within a year or two for therapy. It became clear very quickly that while there were immense benefits there were significant associated hazards, not only for the patients, but also for the operators of the equipment. Simple radiation protection measures were implemented within a decade or two and radiation protection for physicians and other operators has continued to evolve over the last century driven by cycles of widening uses, new technologies, realization of previously unidentified effects, development of recommendations and regulations, along with the rise of related societies and professional organizations. Today, the continue acceleration of medical radiation uses in diagnostic imaging and in therapeutic modalities not imagined at the turn of this century, such as positron emission tomography, calls for constant vigilance and flexibility to provide adequate protection for the growing numbers of medical radiation workers.

Within a few months of discovery, X - rays were being used worldwide for diagnosis and within a year or two for therapy. It became clear very quickly that while there were immense benefits, there were significant associated hazards, not only for the patients, but also for the operators of the equipment. Simple radiation protection measures were implemented within a decade or two and radiation protection for physicians and other operators has continued to evolve over the last century driven by cycles of widening uses, new technologies, realization of previously unidentified effects, development of recommendations and regulations, along with the rise of related societies and professional organizations. Today, the continue acceleration of medical radiation uses in diagnostic imaging and in therapeutic modalities not imagined at the turn of this century, such as positron emission tomography, calls for constant vigilance and flexibility to provide adequate protection for the growing numbers of medical radiation workers.

This chapter includes thyroid anatomy, physiology, and radiopharmaceuticals used for nuclear medicine imaging. There are normal images, as well as many images and text for common thyroid conditions. The chapter also contains issues related to the radioiodine therapy of both benign conditions and thyroid cancer. Parathyroid and salivary gland imaging is presented, as well.

This chapter is focused on non-PET neoplasm imaging and radionuclide therapy. Gallium-67, thallium-201 chloride, technetium-99m sestamibi, pentetreotide, and antibody imaging are included. There is a discussion of breast-specific gamma camera imaging, as well as lymphoscintigrapy. Therapeutic agents for lymphoma, hepatoma, and hepatic metastases are presented.

This chapter discusses the legal requirements for operation of a nuclear medicine department. Also included are aspects related to required training, surveys, instrument calibration, waste disposal, and receipt and transport of radioactive materials. There is also a section on biologic effects of radiation.

National Council on Radiation Protection and Measurements Commentary 27 examines recent epidemiologic data primarily from low-dose or low dose-rate studies of low linear-energy-transfer radiation and cancer to assess whether they support the linear no-threshold model as used in radiation protection. The commentary provides a critical review of low-dose or low dose-rate studies, most published within the last 10 y, that are applicable to current occupational, environmental, and medical radiation exposures. The strengths and weaknesses of the epidemiologic methods, dosimetry assessments, and statistical modeling of 29 epidemiologic studies of total solid cancer, leukemia, breast cancer, and thyroid cancer, as well as heritable effects and a few nonmalignant conditions, were evaluated. An appraisal of the degree to which the low-dose or low dose-rate studies supported a linear no-threshold model for radiation protection or on the contrary, demonstrated sufficient evidence that the linear no-threshold model is inappropriate for the purposes of radiation protection was also included. The review found that many, though not all, studies of solid cancer supported the continued use of the linear no-threshold model in radiation protection. Evaluations of the principal studies of leukemia and low-dose or low dose-rate radiation exposure also lent support for the linear no-threshold model as used in protection. Ischemic heart disease, a major type of cardiovascular disease, was examined briefly, but the results of recent studies were considered too weak or inconsistent to allow firm conclusions regarding support of the linear no-threshold model. It is acknowledged that the possible risks from very low doses of low linear-energy-transfer radiation are small and uncertain and that it may never be possible to prove or disprove the validity of the linear no-threshold assumption by epidemiologic means. Nonetheless, the preponderance of recent epidemiologic data on solid cancer is supportive of the continued use of the linear no-threshold model for the purposes of radiation protection. This conclusion is in accord with judgments by other national and international scientific committees, based on somewhat older data. Currently, no alternative dose-response relationship appears more pragmatic or prudent for radiation protection purposes than the linear no-threshold model.

This chapter deals with PET/CT neoplasm imaging. It includes extensive information on the appropriate uses and interpretation of flourine-18 fluorodeoxyglucose scans. Other PET radiopharmacueitcals are also covered such as fluorine-18 sodium fluoride and gallium-68 agents, as are recent developments for prostate cancer imaging.

This chapter covers the radionuclides, techniques, and indications for musculoskeletal nuclear medicine imaging. Also included are examples of normal and abnormal images for commonly encountered clinical issues such as trauma, neoplasms, infection, and other benign conditions. Bone mineral density applications and therapy for osseous metastases is included.