In January 2021, the National Council on Radiation Protection and Measurements (NCRP) issued a statement along with its accompanying documents, recommending that gonadal shielding should not be used routinely during abdominal and pelvic radiography, and that federal, state, and local regulations and guidance should be revised to remove any actual or implied requirement for routine gonadal shielding. Given its direct relevance to Japan, Japan Health Physics Society established a working group (WG) in March 2021 to translate it into Japanese, make Japanese translation publicly available, and publish a review article. In June 2021, the WG published Japanese translation in this journal. While preparing translation, the WG recognized the need of supplementary explanations for several aspects to help better understand NCRP Statement No. 13. The first aspect is a series of discussions toward a consensus formation made in various relevant US associations and organizations, leading to a statement. The second is underlying science for heritable genetic effects, shielding, and imaging. The third is exemplification of concrete cases for more practicality. This review article therefore aims to address these aspects.

When performing radiation protection for neutrons at nuclear reactor workplaces, accelerator workplaces, and RI workplaces, etc. (hereinafter referred to as workplace), it is important that the measured values of neutron survey meters and personal dosimeters are reliable values. The reliability of measured values is estimated by measuring with calibrated measuring instruments which ensure the traceability, and then adding the accuracy to the measured value. Traceability-ensured calibration means that the results measured by using neutron survey meters etc. can be traced back to the standard value of the primary standard laboratory without interruption. The accuracy can be indicated by adding the estimated uncertainty. Here, the method of estimating uncertainty is introduced, then two examples of the estimation of uncertainty are also introduced; the first example is the uncertainty estimated when the end user’s neutron survey meter is calibrated in the secondary laboratory, and the second one is the uncertainty estimated when the end user measures neutron dose with neutron survey meters in the workplace. Note that neutron measuring instruments such as neutron survey meters, etc. do not have good response characteristics to neutron energy compared with the response characteristics of photo dosimeters to photon energy. Therefore, it should be fully noted that the measurement of the dosimetry in the workplace and the estimation of uncertainty are greatly affected by both response characteristics of dosimeters and neutron energy spectrum in the workplace.

In 1994, the IAEA published technical reports series No. 364 entitled “Handbook of Parameter Values for the Prediction of Radionuclide Transfer in Temperate Environments” (hereafter, TRS-364). Data in TRS-364 have been used in environmental radiation dose assessments in Japan. About ten years after TRS-364, IAEA started to revise the handbook and finally produced two TRS books Nos. 472 and 479; TRS-472 was published in 2010 to follow-up TRS-364 considering climate condition dependent parameter values and TRS-479 was published in 2014 to assess dose to wildlife and whole body is its target, while TRS-364 and 472 were for edible parts. These two handbooks are useful for estimating the migration and transfer of radionuclides in various types of environments. As contributors of these handbooks, we reported herewith some specific background conditions for these publications, especially focused on the data from Japan. In TRS-364, nine Japanese papers were used, but only several data were adopted in the handbook. In TRS-472 and TRS-479, more Japanese data sets, such as soil-to-rice transfer factors and soil-soil water distribution coefficients, were included successfully. It was probably because of the international scientists participated in the IAEA meetings for these TRS publications recognized that the data from our group and other Japanese were highly reliable.

The International Commission on Radiological Protection (ICRP) has published a report of ICRP Publication 147. This publication has consolidated and expanded the concept of effective dose developed by ICRP. Effective dose has been used as a valuable tool for use in the optimization of protection and retrospective demonstration of compliance for regulatory purpose. The use of equivalent dose should be discontinued to avoid confusion of the same unit of Sievert between effective dose and equivalent dose and to set the limits on organ/tissue doses to prevent tissue reactions. The ICRP has considered effective dose an approximate indicator of possible risk of stochastic effects at low doses below 100 mSv. The estimate of effective dose can be used for comparing medical exposures among different diagnostic modalities including computed tomography and nuclear medicine. However, it is emphasized that use of effective dose is not substitute for the risk of a specific individual/organ since there is an uncertainty of the risk estimate due to low doses and simplified concept using tissue weighting factors that are averaged across all ages and both genders for hypothetical populations. The present article provides a brief summary and commentary of the key issues on the report. The concept of detriment behind calculation of tissue weighting factors in effective dose is reviewed.

Since the end of 2019, we have faced a COVID-19 (coronavirus disease 2019) pandemic with SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). Medical institutions must treat COVID-19 patients while preventing health care workers and other patients from nosocomial infections. COVID-19 also needs to be considered in a case of radiation emergency medicine. Although radioactive materials (RI) and SARS-CoV-2 are different, they have much in common in health risk management when we receive such patients in that they are undetectable by all our five senses and require personal protective equipment (PPE). On the other hand, there are some notable points on preparedness and response for their risk management. We cannot detect SARS-CoV-2 in real-time but can sterilize them with alcohol-based hand sanitizer. RI is difficult to be decontaminated entirely but detectable in real-time with a suitable radiation survey instrument. Under the COVID-19 situation, it is a great challenge to deal simultaneously with a radiation protection and an infection control, especially in an emergency situation of radiation exposure. In order to overcome such difficulty, we at first compare the similarity and difference of risk management between RI exposure and SARS-CoV-2 infection. Then the points of attention are introduced how to manage the radio-contaminated patients with a coexistence of SARS-CoV-2, including the fundamental concept of zoning, PPE, and hand-over of equipment.