2020 Health Physics Society Midyear Meeting & ExhibitionTPM-A
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| Chair(s): Kathy Held, Donald Miller |
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TPM-A.1 14:00 Radiological Health at FDA: A Review of Programs and Findings, Past and Present. Spelic David C*, Food and Drug Administration david.spelic@fda.hhs.gov
The Food and Drug Administration has a long history of radiological health activities directed at medical x-ray imaging. Beginning with two benchmark studies of population exposures conducted in the U.S. during 1964 and 1970, the Agency has conducted a number of activities that document the state of clinical practice in diagnostic radiology, including both medical and dental x-ray imaging. Studies have focused on specific imaging modalities, including general radiography, fluoroscopy, mammography, computed tomography and dental imaging, providing a series of snapshots over time that permit a study of trends in the state of practice. One such effort- the Nationwide Evaluation of X-ray Trends, a collaboration begun in 1972 with the Conference of Radiation Control Program Directors - continues to this day. This presentation provides a summary of past and present radiological health activities at the Agency and discusses how those activities have contributed to broader collaborative efforts aimed at documenting and improving the quality of diagnostic x-ray practice. |
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TPM-A.2 14:25 NCRP SC4-9 Report on Medical Radiation Exposure of Patients in the United States. Mahesh M*; Mettler FA; Vetter R; Miller DL; Frush DP; Bhargavan Chatfield M; Royal HD; Milano MT; Spelic DC; Elee, JG; Ansari A; Bolch W; Guebrt G; Sherrier R; Chambers C , Johns Hopkins University, University of New Mexico, US Food and Drug Administration, Stanford University Medical School, American College of Radiology, Washington University, University of Rochester Medical Center, Louisiana Dept of Environmental Quality mmahesh@jhmi.edu
The NCRP report 160 (2009) demonstrated the rapid and dramatic increase in diagnostic and interventional patient medical radiation exposures between early 1980 up to 2006. The report led to the examination of medical radiation exposures by many groups both in the United States and Internationally. NCRP SC 4-9 formed in 2016 was charged to prepare a report to evaluate changes in medical x-ray exposure since NCRP 160. The charge to the committee was to assess the number and types of medical x-ray procedures, the average per caput and collective effective doses and the changes since 2006. Even though NCRP 160 was published in 2009, the data was as of 2006. Similarly, the new report (NCRP 184) slated for publication in late 2019, reports data as of 2016. From the onset, the committee members agreed to report effective dose values only for the various medical x-ray procedures and decided not to include organ doses and not include radiation therapy procedures. The publication of new tissue weighting factors (ICRP 103) were accounted and the committee decided to compute collective effective doses using both ICRP 60 and ICRP 103 weighting factors. This was done in order to compare the final results with that of NCRP 160 and to examine the impact of tissue weighting factors. Even though the largest contributor to collective dose among medical radiation exposure is from CT, yet the estimated annual individual effective dose (EUS) was similar to NCRP 160. Overall, the 2016 estimates for collective effective dose (S) and effective dose per capita (EUS) indicates a decline from 2006 by ~15 to 20%. Details of the estimated collective effective dose (S) and effective dose per capita (EUS) for each modality is presented. Along with the details on how the number of procedures and the effective dose for each modality estimated is discussed in this presentation. |
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TPM-A.3 14:50 Estimating Lung Doses to Medical Workers in the Million Person Study (NCRP SC 6-11). Grogan Helen, Cascade Scientific; Dauer Lawrence, Memorial Sloan Kettering; Boice John, NCRP; Yoder Craig*, NCRP Chair SC 6-11 rcraigyoder@gmail.com
NCRP Report No. 178 presents an 11-step process to guide the radiation dose reconstruction process to be applied to the worker groups comprising the epidemiological Million Person Study (MPS). Medical radiation workers make up a large group of individuals occupationally exposed to low doses of radiation (and are a sub-cohort of the MPS), who have been monitored with the use of personal dosimeters when potentially exposed to ionizing radiation, and the measurements have generally been maintained. For epidemiologic studies, it is often assumed that the average dose over the entire organ or tissue (organ dose) is the quantity of interest in the analysis. However, the derivation of organ doses for the medical worker cohort members from monitoring data poses difficult problems because of, among other factors: often extreme inhomogeneity of exposure over the body of personnel for any given procedure type as organs or tissues may only be partially irradiated, for example when medical personnel wear lead aprons; differing degrees and methods of radiation protection; inconsistent wearing of dosimeters by personnel (i.e., at times choosing not to wear dosimeters in order to avoid investigations), combined with poor information, as well as high variability, on the workloads of physicians and technologists (i.e., the number of procedures of a given type conducted monthly or annually); and changing technology and medical procedure protocols. NCRP Scientific Committee 6-11 was charged with the task of describing an optimum approach for using personal monitoring data to estimate lung and other organ doses along with specific precautions applicable to epidemiologic study of medical radiation workers, recognizing many associated uncertainties. |
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TPM-A.4 15:45 Evaluation of Sex-Specific Differences in Lung Cancer Radiation Risks and Recommendations for Use in Transfer and Projection Models (NCRP SC 1-27). Weil Michael M, Colorado State University; Boice John, NCRP; Dauer Lawrence*, Memorial Sloan Kettering dauerl@mskcc.org
Recent results from the study of Japanese atomic bomb survivors, exposed briefly to radiation, finds the risk of radiation-induced lung cancer to be nearly three times greater for women than for men. Because protection standards for astronauts are based on individual lifetime risk projections, this sex-specific difference limits the time women can spend in space (NCRP Commentary 23, 2014). NASA requested that NCRP evaluate the risk of radiation-induced lung cancer in populations exposed to chronic or fractionated radiation to learn whether similar differences exist when exposures occur gradually over years contrasted with the acute exposure received by the Japanese atomic bomb survivors. In response to NASA, NCRP initiated an epidemiologic study of ~150,000 medical radiation workers (~50% women) and additional DOE worker cohorts within the Million Person Study. These studies are viewed in the context of other studies of reasonable quality with estimates of radiation-induced lung cancer when radiation is given gradually over time (e.g., studies of tuberculosis patients, indoor radon, Mayak workers, scoliosis patients). An extensive and comprehensive review is needed of all epidemiologic studies and animal experiments, as well as mechanistic models. In addition, an evaluation of the factors affecting transfer of risk modeling and incorporation within lifetime risk projection are required. NCRP is evaluating the current risk projection model used by NASA for lung cancer life time risk projection and examine whether the new data on low dose rate exposures and sex-specific lung cancer risks will be such as to recommend modifications. |
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TPM-A.5 16:10 Radiation Risk Communication in Medicine. Shogren Angela*, US EPA shogren.angela@epa.gov
Medical professionals feel confident prescribing and performing necessary procedure for patients, but when associated radiation risks are raised, many healthcare professionals may not feel adequately prepared to address patient concerns. Effectively communicating radiation risks to patients is often an afterthought in medical education or merely touched on during general patient communication training. There are two main radiation risk communication pathways in medicine – professional-centered communication (between two or more medical professionals) and patient-centered communication (between a medical professional and a patient). When communicating with patients or other health professionals, it’s imperative to understand the subject’s background, risk perception, and unique situation. While there is no “one size fits all” script, there are tools and techniques that can lead to more effective radiation communication in the medical setting. |
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TPM-A.6 16:35 The ICRP and its Role in Guidance, Communication, and Collaboration . Applegate Kimberly* keapple5123@gmail.com
The International Council for Radiation Protection (ICRP) is an independent, not-for-profit organization with a mission to advance for the public benefit the science of radiological protection, in particular by providing recommendations and guidance on all aspects of protection against ionizing radiation. Founded in 1928, it currently comprises a community of more than 250 globally-recognized experts in radiological protection (RP) science, policy, and practice from more than 50 countries. Committee 3 addresses protection of persons and unborn children when ionising radiation is used in medical diagnosis, therapy, and biomedical research—and since 2017--protection in veterinary medicine. The ICRP Committee 3 has a wide mandate in radiation protection and its members have expertise in diagnostic radiology, radiation oncology, nuclear medicine, medical physics, epidemiology and biostatistics, regulatory application of RP, process and quality improvement, and human and veterinary medicine. We work together with the ICRP committees, and we collaborate with a number of organizations including radiology, medical physics, and regulatory bodies. |