Health physics最新文献

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.

A commentary written by Jan Beyea claimed that the HPS interview of Edward Calabrese on the historical evolution of the linear no-threshold model was unreliable because it overlooked key historical text and statistical concepts. Beyea states that the purpose of his commentary was to defend the integrity of historical figures and committees from the accusation of scientific misconduct as presented by Calabrese. Based on his review of the video series and other documents, he provided what he defined as evidence of errors of fact, reasoning, and statistics to support his position. If true, Beyea's work would have the effect of impugning the reputation of Calabrese, myself, and the credibility of the HPS. This response intends to expose the issues with Beyea's commentary, including mischaracterization of Calabrese's work, lack of objectivity, misleading and factually incorrect statements, reliance on secondary sources, ignoring evidence specifically provided in the video series, and failing to address evidence provided in primary-sourced documents that contradict his conclusions. As a result, the reliability of Beyea's commentary is highly compromised, representing a serious lack of scholarship, research, and objectivity such that it should be retracted by Health Physics Journal based on the Committee on Publication Ethics guidelines. The HPS interview-style documentary reflects historical events based on primary-sourced documents as discovered by Calabrese. Scientific debate on this topic is necessary to progress our field, but the debate must be supported by facts with primary-sourced evidence and not driven by outdated public policies, logical fallacies, or ideology.

Introduction: This research explores the application of advanced geostatistical methods to predict the locations of residual radioactive hotspots at the former Zamzow uranium mine site, located near Three Rivers, TX. The site, part of the broader Lamprecht-Zamzow project, has a complex history, having undergone in situ uranium mining and processing, followed by decommissioning activities. The role of this study is not to set or recommend remediation goals, as this responsibility lies with the State of Texas. Rather, the purpose of the statistical analyses in this work is to present the data objectively, predicting potential contamination at unsampled locations and where further actions may be needed. Importantly, the findings of this study aim to inform state regulators regarding the unrestricted release of the site for landowner use, providing critical insights into the effectiveness of previous remediation efforts. By employing rigorous geostatistical techniques on survey data collected by environmental services contractors, this study models the spatial distribution of contamination referred to as "hotspots" with precision. This research marks an important advancement toward a scientifically grounded, objective approach in assessing radioactive site remediation and informing future decisions regarding site decommissioning and land restoration at former uranium sites. Importantly, the statistical analysis in this work demonstrated a clear reduction in the number of hotspots after site remediation, highlighting the effectiveness of the intervention.

Effective decision-making in a nuclear emergency is an essential element of achieving the goals of Emergency Preparedness and Response (EPR). Within the International Atomic Energy Agency's (IAEA) General Safety Requirements (GSR) Part 7, preparedness goals are stated generally as having adequate capabilities in place for an effective response. Past nuclear accident experience has demonstrated the complexities involved in urgent and early phase protective action decision-making which is characterized by a distinct lack of information resulting in poor or inappropriate decisions that do more harm than good. The Operational Planning Process (OPP) has been developed by many professional militaries around the world as a means of dealing with equally complex situations. In this work we explore a component of the OPP, wargaming, and apply it to the preparedness phase of a nuclear emergency to validate response planning. The work demonstrates the usefulness of the activity at improving urgent and early phase decision-making and decision-making tool development. The concept effectively addresses several lessons learned from past nuclear incidents as well as continued observations calling for improved tools to better integrate a scientific and technical understanding into a justified and optimised, all hazards emergency response environment.

On June 9 th and 10 th , 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%).

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.

Accurate assessment of external radiation dose rates from 137 Cs is essential for evaluating radiological risk in environmental and occupational settings. This study refines dose conversion coefficient calculations by incorporating depth-dependent soil density and addressing limitations in conventional methods that assume constant soil density. We calculated dose conversion coefficients for 137 Cs in soil, considering both exponential and Gaussian distributions of activity concentration. Using two models, one with constant density and another with variable density as a function of depth, we compared dose rates to quantify the effect of soil density variations. Results indicate that dose rates are consistently higher when depth-dependent density is applied. The effect is more pronounced when 137 Cs activity is distributed over larger depths (i.e., greater relaxation lengths) or when broader Gaussian distributions are considered. This suggests that assuming constant soil density may lead to underestimations of dose rates, especially in heterogeneous or compacted soils. Our findings emphasize the importance of accounting for density variability in dose calculations to enhance radiological risk assessments for areas contaminated with 137 Cs.