Patterns and trends of population radiation exposure and projected the risk of exposure-induced death from gamma camera examinations in Yazd Province.

INTRODUCTION: The use of nuclear medicine examinations as imaging modalities has recently increased. This study aimed to assess the radiation dose delivered to patients from common diagnostic nuclear medicine examinations and estimate the risk of exposure-induced death (REID). In addition, the frequency of nuclear medicine procedures were evaluated from 2015-2018. MATERIALS AND METHODS: The data were collected from adult patients who had undergone cardiac, skeletal, renal, lacrimal, and thyroid imaging. For each patient, the effective dose was calculated using dose conversion factors, and REID was estimated using PCXMC. The frequency of examinations between 2015 and 2018 was obtained from the hospital information system (HIS). RESULTS: The highest estimated effective dose was attributed to the scans of myocardial stress (8.09 ± 1.28 mSv), myocardial rest (5.59 ± 1.27 mSv), and thyroid imaging (3.93 ± 0.55 mSv). In addition, cardiac stress examination had the highest REID values for solid cancers (212.5 ± 67.5) and bone scans had the highest REID values for leukemia (11.5 ± 2.5). A large increase in the number of myocardial perfusion scans was a significant contributor to an increase in collective effective dose from 23.37 man-Sv in 2015 to 49.47 man-Sv in 2018, a compound annual growth rate (CAGR) of 26%. CONCLUSION: Although the annual frequency and per capita effective dose of nuclear medicine procedures in Yazd Province increased continuously, they were comparably lower than those reported for other countries. Despite this, the cancer risks of nuclear medicine scans at the individual level are negligible (around 0.01% excess fatal cancer risk), yet the increasing tendency for these examinations could be of concern.

Radiation dose and risk of exposure-induced death associated with common computed tomography procedures in Yazd Province.

PURPOSE: This survey was conducted to evaluate the radiation dose delivered to the patients through different CT procedures along with its corresponding risks in Yazd province. METHOD: Data for the five most common procedures were collected from six institutions from September 2017. The effective dose for each patient was estimated by ImpactDose software. The risk of exposure-induced death (REID) was calculated by coupling the BEIR VII model and ICRP 103 data for the Asian population. RESULTS: The median effective doses for the five most common procedures, in descending order, were as follows: 5.19 mSv for abdomen-pelvis, 3.30 mSv for routine chest, 3.00 mSv for chest HRCT, 0.76 mSv for Brain and 0.47 mSv for sinus. Averaged over all the procedures, the ratio of maximum to minimum of effective dose was 90-fold. The highest associated risk was tied to high-resolution CT scans for women which was estimated to be 1 exposure-induced death related to 2096 scans performed on a 20-year old patient. CONCLUSION: The estimated effective doses for all the procedures except sinus were comparably low, however, the variations among patient doses, even for a given procedure, were substantially high, indicating that further optimization processes need to be undertaken. Moreover, it was estimated that approximately 2000 scans of abdomen-pelvis performed on 20 year-old women could result in 1 radiation-induced cancer death, which in large scales may cause drastic health issues. In this regard, several approaches, one of which is the implementation of DRLs, can be suggested to reduce the collective dose from CT scans.

European trends in radiology: investigating factors affecting the number of examinations and the effective dose.

The advances in technology have led to a growing trend in population exposure to radiation emerging from the invention of high-dose procedures. It is, for example, estimated that annually 1.2% of cancers are induced by radiological scans in Norway. This study aims to investigate and discuss the frequency and dose trends of radiological examinations in Europe. European Commission (EC) launched projects to gain information for medical exposures in 2004 and 2011. In this study, the European Commission Radiation Protection (RP) reports No. 154 and 180 have been reviewed. The RP 154 countries' data were extracted from both reports, and the average variation trend of the number of examinations and effective doses were studied. According to the results, plain radiography and fluoroscopy witnessed a reduction in the frequency and effective dose per examination. Nevertheless, European collective dose encountered an average increase of 23%, which resulted from a growing tendency for implementation of high-dose procedures such as CT scans and interventional examinations. It is worth noting that most of the CT procedures have undergone an increase in effective dose per examination. Although demand and dose per examination in some radiological procedures (such as intravenous urography (IVU) have been reduced, population collective dose is still rising due to the increasing demand for CT scan procedures. Even though the individual risks are not considerable, it can, in a large scale, threaten the health of the people at the present time. Due to this fact, better justification should be addressed so as to reduce population exposure.