Health physics最新文献

The International Atomic Energy Agency (IAEA) has played a critical role in the development and establishment of contemporary radiation safety standards, beginning with its safety standards program launched in 1958. These standards have been developed and/or reviewed in continuous cooperation with the International Commission on Radiological Protection (ICRP) and United Nations Scientific Committee on the Effects of Atomic Radiation. This long-lasting partnership ensures that the latest scientific findings are integrated into international safety standards, fostering global harmonization. In 2021, the ICRP announced a review and potential revision of the system of radiological protection, which could lead an update of 2007 Recommendations (ICRP Publication 103) and called for cooperation and discussion among all relevant international stakeholders. Since then, numerous discussions among radiation protection professionals worldwide have taken place at key international meetings and events, focusing on the proposed changes and highlighting the need for further dialogue and cooperation in potential future revision. Any changes to the system will have consequences that must be carefully considered and justified. Potential revisions should be thoroughly evaluated to ensure they enhance the safety for the public, workers, patients, and the environment, while maintaining the system's stability and respecting national and regional specificities. The IAEA's work on providing for application of the current set of IAEA safety standards in its Member States aims to ensure that safety standards remain relevant, effective, and also adaptable to emerging challenges. It is important to stress the need for cooperation among all relevant international stakeholders to maintain the system's global applicability. Reviews of this work indicate that the current system is robust and effective, but with challenges primarily related to the way and feasibility of implementation and interpretation of safety standards rather than associated with the system itself.

This paper aims to discuss some of the challenges (and opportunities) associated with NORM and sustainability. Practical examples are used to demonstrate that the strict application of operational quantities, such as exemption values or surface contamination limits, can restrict the use of products that could be used in an unrestricted manner from a risk-based perspective. This can lead to the devaluation of material goods, such as phosphogypsum, radioactively contaminated scrap, and lead-containing 210Pb, among others, which clash with the objectives of the circular economy and thus also sustainability. The paper exemplifies the linkages between radiation protection and sustainability and aims to open a discussion on the adverse social and economic effects of the current practice. This is particularly relevant given the further development of the radiation protection system initiated by ICRP. Some preliminary ideas for this discussion are described.

Computed tomography is acknowledged as the most widely used imaging technique in both adults and children. Although computed tomography offers valuable diagnostic information, it contributes to a high radiation dose and poses relatively high risks of stochastic effects to patients. Stochastic risks are of special concern in pediatric imaging since children are more vulnerable to effects of ionizing radiation than adults. Therefore, the justification of pediatric computed tomography examinations is of paramount importance to critically weigh the benefits of computed tomography against the individual detriment. This study evaluates the current radiological justification for pediatric computed tomography in Kenya and propose strategies to enhance justification. An extensive literature review on pediatric computed tomography justification was explored based on the international guidelines of ICRP and IAEA and individual publications. The foundation of the review focused on the 3 A's: awareness, appropriateness, and audits as tools to ensure proper justification. The recommendations and guidelines proposed in this study can guide in the implementation of the 3 A's in the country.

This paper summarizes the presentations and panel discussion held at Plenary Session 1 of the 16th IRPA International Congress/69th Health Physics Society Annual Meeting, in Orlando, FL, in July 2024. Plenary Session 1 discussed the basics of the systems of radiological protection (RP) for ionizing radiation (IR) and non-ionizing radiation (NIR) and included five presentations and a panel discussion. Rodney Croft, Chair of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), delivered the first presentation. Croft introduced the System of RP for NIR and provided an overview of ICNIRP's coverage and current areas of work. Werner Rühm, Chair of the International Commission on Radiological Protection (ICRP), delivered the second presentation. He gave an overview of the System of RP for IR and covered the key principles of justification, optimization, and dose limitation, including the current plans of ICRP toward the envisaged revision of the System of RP. The third speaker, Sigurður Magnús Magnússon, from the International Radiation Protection Association (IRPA), provided the perspective of the RP professionals on the development of the Systems of RP for IR and NIR. Emilie van Deventer, from the World Health Organization (WHO), presented WHO's views of both Systems of RP and discussed the relevant current activities of WHO with regard to IR and NIR. Kathryn Higley, President of the National Council on Radiation Protection and Measurements (NCRP), delivered the final presentation. Higley outlined the history of NCRP, the differences between ICRP and NCRP, and discussed the role of the NCRP in the System of RP, including NCRP's role to analyze mechanisms of interaction of NIR with biological systems, including humans. The session concluded with a fruitful panel discussion, where the audience had the opportunity to ask the five invited speakers questions.

The linear no-threshold (LNT) model was introduced into the radiological protection system by the International Commission on Radiological Protection (ICRP) in 1966. The appropriateness of this model is still hotly debated today. Based on a recently published article, we summarize recent results in radiobiology and epidemiology and discuss their impact on the use of the LNT model regarding radiological protection. The scientific results published in radiobiology and epidemiology have strengthened our scientific knowledge of cancer risks associated with low dose and/or low dose-rate radiation exposure. In radiobiology, early stages of mutational carcinogenesis are considered to play a key role in carcinogenesis, with linear responses at doses as low as 10 mGy. Today, some non-mutation mechanisms appear clearly as non-linear, but their impact on the overall carcinogenesis process remains difficult to assess. In epidemiology, excess cancer risk has been observed at dose levels of 100 mGy or less. Some findings suggest that for some cancers, non-linear dose relationships may exist, but overall, the LNT model does not seem to seriously overestimate the risks of cancer at low doses. Overall, current results in radiobiology or epidemiology do not demonstrate the existence of a dose threshold below which the risk of radiation-induced cancer would be zero. Uncertainties remain, but if such a dose threshold existed for all solid cancers, it could not be greater than a few tens of mGy. In conclusion, we consider that the recent scientific knowledge does not call into question the use of the LNT model to assess cancer risks associated with exposure to ionizing radiation for the purpose of radiological protection. Today, the use of this model seems reasonable, and no other dose-response model seems to be more appropriate or justified for radiological protection purposes.

On June 9th and 10th, 2025 the Health Physics Society (HPS) and National Council on Radiation Protection and Measurements (NCRP) jointly sponsored two open forums with the hopes of discussing and responding to constituent beliefs regarding a series of nuclear-related Executive Orders (EOs). The HPS and NCRP leaders were joined by members from the American Academy of Physicists in Medicine (AAPM), and the Conference of Radiation Control Program Directors (CRCPD) as panelists to help respond and moderate the forums. The forums focused on three of the nine relevant EOs, and, while varying opinions were shared, three common themes were strongly supported: First, many of the constituents support change, particularly regulatory harmonization (205/212, 97%), and the time to make changes [now] is appropriate due to these EOs. Second, the constituents believe that these EOs will have a significant impact on the nuclear fields (420/468, 90%). Third, the constituents strongly support the United States in increasing its use of nuclear power (236/245, 96%).

The accidental ingestion of radioactive iodine is known to increase the risk of thyroid cancer and thyroid dysfunction; hence, strict radiation safety measures are required when handling it. In a previous study, we demonstrated that absorbing radioactive-iodine-containing wastewater using a water-absorbent polymer with cyclic oligosaccharides that selectively capture iodine, followed by natural drying, effectively separates at least 80% of the iodine from the wastewater. However, because natural drying requires approximately 2 wk, faster processing is essential to improve the efficiency of this wastewater treatment. Hence, we propose a method for quickly separating iodine from wastewater via heat drying. This study aimed to compare radioactive iodine volatilization levels between samples subjected to heat-drying- and natural-drying-based iodine and water separation. Na125I was added to purified water and artificial urine to prepare simulated waste liquids containing iodine at concentrations equivalent to those in the urine of patients undergoing radioactive iodine treatment. The prepared simulated waste liquids were poured into containers containing a superabsorbent polymer, dried in a thermostatic dryer set at 100 °C for 9 h, and subsequently stored for 90 d. The iodine residual rate in the simulated waste liquids was determined by measuring 125I radioactivity. At the end of the heat-drying process, the iodine residual rates in the simulated waste liquids prepared with purified water and artificial urine were 0.452 and 0.783, respectively. When absorbed in 1 g of superabsorbent polymer, the residual rates increased to 0.956 and 0.952, respectively. Over the following 82 d, the residual rates decreased by approximately 10%. Thus, by absorbing radioactive-iodine-containing wastewater into a highly water-absorbent polymer and then applying heat drying, iodine can be effectively separated from the wastewater while limiting its volatilization to less than 15%.

Conventional occupational radiation exposure monitoring relies on cumulative dose data from personal dosimeters without providing information on when, where, or under what conditions exposure occurs. This lack of context limits analysis of causal factors, evaluation of protective behaviors, and the effectiveness of safety education. This study aimed to develop and clinically implement an integrated information system for occupational radiation exposure by combining dose data, spatiotemporal movement records, and angiography-related radiation information. We also assessed its utility and potential for improving radiation safety management. The system was implemented for 1 mo in a clinical angiography suite. It integrated (1) personal digital dosimeters recording dose and time, (2) Bluetooth Low Energy beacons tracking healthcare workers' positions and movements, and (3) Radiation Dose Structured Reports providing exposure details. Data were synchronized to reconstruct when, where, and under what conditions exposure occurred. The system identified high-risk positions near x-ray tubes (Beacon IDs 1-3), where exposure was greatest. Avoidance behaviors were also detected, such as movement to low-risk areas (e.g., Beacon ID 8) before irradiation. We successfully developed, implemented, and evaluated the system, demonstrating its utility for improving radiation safety management. The insights gained support targeted interventions and the refinement of safety protocols, with potential for broader use in diverse radiation-controlled settings.

An accurate internal dosimetry is important in 131I radionuclide therapy. In patients who have undergone a thyroidectomy, organs other than the thyroid absorb higher doses as the radionuclide is transported through the body because most of the thyroid gland is removed, and it cannot retain the 131I. The primary objective of this study is to compare the absorbed doses in at-risk organs due to intake of 131I after thyroidectomy vs. a healthy thyroid scenario. The biokinetic model of internal dosimetry for healthy thyroid as proposed by the International Commission on Radiological Protection (ICRP) in Publication 137 and a radiation transport simulation in Monte Carlo N-Particle 6 (MCNP6) were used. From the biokinetic model, average activities of 131I over a 30 h period were obtained, and these activities were used as source terms in MCNP6 simulations transporting gamma rays and beta particles to estimate absorbed doses in at-risk organs. The use of average activities is a new approach proposed in this study. Once the internal dosimetry model for a healthy thyroid was complete and functional, it was adapted for the scenario following thyroidectomy. This involved changing the transfer coefficients connected with the thyroid in the biokinetic model to constants proposed by Taprogge et al. in 2021. With this adjusted model, average activities of 131I over a 30-h period were obtained again and used as source terms in MCNP6 simulations of a patient following thyroidectomy, and from this simulation, absorbed doses in at-risk organs were estimated. These coefficients had not been used to estimate organ doses using MCNP. The 131I activity in the thyroid gland was found to be 20.4% of the initial administered dose in the scenario with a healthy thyroid vs. 0.64% following thyroidectomy. After thyroidectomy, all organs other than the thyroid absorbed higher radiation doses compared to the scenario with a healthy thyroid. The results of this study allow comparison of the absorbed doses between the scenarios of a healthy thyroid and after thyroidectomy, showing substantial differences between the modeled scenarios, which underscores the need to consider the larger context when assessing radiological impact on at-risk organs during 131I therapy.