Health physics最新文献

Strontium is a ubiquitous element due to its presence, of both natural and anthropogenic origin, in all environmental compartments. In stable or radioactive form, it has numerous industrial and medical applications and is also used in research projects. For radioactive isotopes of strontium, the risk of exposure through irradiation or internal contamination is therefore very real. In addition, in the current international context, CBRN (chemical, biological, radiological, nuclear) risks have increased and diversified, with a more present terrorist component. Among the possible scenarios, malevolent acts such as the use of a "dirty bomb" containing sources of radionuclides (including strontium) currently used in industry, in the medical field, or for research must be envisaged. As a result, the authorities need to have effective and operational tools of prevention and protection at their disposal to be able to respond to these growing threats, which expose not only the civilian population but also the military and first responders. This review presents the most relevant up-to-date data, notably covering biokinetics, health effects, and pharmacological treatments following internal contamination exposure to radioactive strontium compounds. Following this critical review of existing research work, the need for additional advanced knowledge is emphasized in the fields of toxicity and medical treatments, which are fundamental areas in radiation protection.

FLASH radiation therapy is a promising modality that delivers radiation at ultra-high dose rates, potentially minimizing normal tissue toxicity while maintaining tumor control. However, conventional dosimetry tools often fail at ultra-high dose rates, necessitating alternative solutions. Alanine dosimetry, a passive technique known for its dose-rate independence and tissue equivalence, presents a compelling option. While other studies have used alanine pellets, this study investigates the applicability of alanine powder dosimeters in FLASH radiation therapy. Thirteen dosimeters were irradiated with doses from 10 to 100 Gy using a 137Cs source. Six samples were used to construct dose-response calibration curves, while the remaining seven were used for validation. Peak-to-peak amplitudes of the electron paramagnetic resonance signal were normalized using internal standards and sample density. Dose estimates based on density-normalized calibration were within ±4.2% of expected values, demonstrating strong linearity (R2 > 0.99) and clinical viability. While post-processing time remains a limiting factor, this work affirms the potential of alanine powder as a reliable tool for FLASH dosimetry, especially for high-dose, dose-rate-independent measurements.

A comparison among three models (Birattari Conic Plume, HotSpot, and NCRP 123 Gaussian distribution) has been carried out concerning the release of air-activated radionuclides during bombardment of a H218O target in a medical cyclotron with two different proton energies: 10 MeV and 18 MeV. Under worst-case meteorological conditions, the diffusion of 13N, 40Cl, 37S, and 41Ar has been investigated. The total amount of induced activation (Bq) during different beam times has been calculated for each isotope, and the three models have been used to assess the dose to the residential population located 100 m from the release point, for a fixed beam current of 100 µA. The results demonstrate that a facility for medical isotope production, even under heavy workload (3,000 µA h-1 wk-1), will not lead to a significant increase in the dose to the surrounding population.

Effective radiation monitoring is crucial for ensuring public security and safety, particularly in the event of nuclear (e.g., nuclear accident, fallout, etc.) or radiological (e.g., radiation source spill, dirty bombs, etc.) emergencies. Traditional monitoring methods often lack real-time capabilities and comprehensive data visualization and analysis, which can delay response time and increase further risks. To address this gap, this research proposes an Advanced Radiation Detector for real-time radiation monitoring. The novelty is in its use of an internet of things (IoT)-based framework to collect and transmit all the data (e.g., radiation level, temperature, pressure, humidity, and air quality) via a GSM module to web cloud all from one device with enhanced visualization in the self-made website. The study setup will obtain data across the area of the Military Institute of Science and Technology (MIST), Mirpur Cantonment, Dhaka, Bangladesh, using this Advanced Radiation Detector. This data is visualized by creating a scatter circle map of spatial distribution of radiation measurements. By visualizing radiation data taken from the self-developed detector and visualizing it using the self-made website, we found the Advanced Radiation Detector meets its objectives perfectly. This research aims to enable real-time radiation monitoring and provides timely insights for emergency responses. By integrating IoT in the system, it has directly overcome the limitation of traditional methods. The Advanced Radiation Detector has immense potential to improve security and safety measures. The current Rooppur Nuclear Power Plant (RNPP) development in Bangladesh emphasizes the necessity of customized solutions for efficient radiological risk management. In order to improve Bangladesh's nuclear safety framework, this study presents a revolutionary IoT-based radiation monitoring system that uses machine learning for real-time assessment and predictive analytics.

We analyzed the US Nuclear Regulatory Commission event notifications related to unplanned exposure to fetus or embryo for events that occurred between 1 January 2005 and 31 December 2024. A total of 39 events were identified, 28 related to therapeutic and 11 to diagnostic nuclear medicine; no events related to brachytherapy or gamma teletherapy were found. The number of events fell during the study period (2005-2009: 15; 2020-2024: 6). The radioisotope in most (71.8 %) of the events was 131I. A pregnancy test was performed in 21/28 therapy events and in 0/11 diagnostic events. The estimated age of the fetus ranged from 1 to 26 wk (mean 5.7 wk); in two therapy events, conception occurred after the administration of the radiopharmaceutical. The mean reported estimated dose to the fetus was 260 mSv (SD: 190; range 20-860) for the therapy events and 17 mSv (SD: 6; range 10-26) for the diagnostic events. Unplanned fetal exposures are occurring; for therapy events, the estimated dose to the fetus is often high enough that adverse effects are possible. We suggest institutions review their policies on patient consent and pregnancy testing.

The 1956 recommendation by the US National Academy of Sciences (NAS) Biological Effects of Atomic Radiation (BEAR) I Genetics Panel to transition from a threshold to a linear dose response model for hereditary effects had a profound impact on environmental/occupational risk assessment, affecting policies/practices of US regulatory agencies, having much influence on regulations worldwide to the present. The recommendation gained influence due to the authority of the NAS, the prestige of the Panel, and the claim of a striking degree of uniformity among six independent estimates of radiation-induced hereditary risk. This claim was orchestrated by panelist James Crow who removed conflicting findings from the nine panelists who submitted estimates, acting with the approval of the entire Panel. These misrepresentations were ensured by the US NAS President who refused to share the Panel's technical reports and related documents with the scientific community. Ironically, the mouse mutation rate data used by the panelists who calculated risk estimates for either mouse or Drosophila were incorrect due to falsification by panelist William Russell without their knowledge. This action led to greatly exaggerated mutation risks and enhanced their overall false impression of agreement/scientific convergence. The actions of Crow were such that the already grossly inflated and falsified risk estimates of the panelists were made to appear in reasonably good agreement. These massive and compounded errors and deceptions have significantly affected regulatory practices for cancer risk assessment in the US and globally to the present. The present paper provides for the first time in the scientific literature an assessment of the unpublished technical reports of each of the nine participating geneticists of the BEAR I Genetics Panel and provides the basis for the above critical conclusions.

Radiation-based medical techniques and devices provide significant benefits to patients through the diagnosis, treatment, and management of illness and disease. Documenting trends and frequency of use offer important insights into radiation protection and help address gaps in the documentation of medical exposures. Here, we present the retrospective Canadian data collected for the recent United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) global survey on medical exposure. The global survey included three modality categories: diagnostic and interventional radiology, nuclear medicine, and radiotherapy and reports the total number of devices, physicians, examinations, and procedures. Due to the inability to collect high-quality dose data from Canadian sources, the average doses for specific examinations and treatments were estimated using internationally pooled data. The total annual per capita dose from medical exposures was determined to be 1.56 mSv, excluding radiotherapy, resulting in approximately 47% of all radiation doses received by Canadians, compared to natural, industrial, and consumer product sources. This assessment of Canadian medical radiation exposures contributes to global improvement of patient protection, helps establish trends, and identifies where Canadian data collection is lacking, particularly dose data.

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. Na 125 I 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 125 I 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.

Nearly 400 million years ago, vertebrate life began to transition from a purely aquatic existence to the terrestrial environment. Concurrently, exposure to ionizing radiation from cosmic and geologic sources increased substantially. Around the same time, vertebrate hematopoietic stem cells (HSCs) migrated from the liver and peri-nephric parts of the abdomen into the interior of bones. Interestingly, among today's vertebrates, only fish lack bone marrow. All other extant vertebrates maintain their HSCs in the bone marrow cavity. We propose protection from sub-lethal DNA damage to these long-lived radiation-sensitive cells because of exposure to ionizing radiation is why HSCs are sequestered with the bone marrow cavity. Our calculations support this hypothesis. Residence in the bone marrow cavity reduced exposure to penetrating background radiation and the concomitant DNA damage by at least 20%. This reduction was even more significant radio-biologically when considering the relatively hypoxic conditions within the bone marrow cavity and oxygen's role in enhancing radiogenic DNA damage. This may be particularly relevant considering the oxygen-rich atmosphere in existence at the time of transitioning to a terrestrial habitat. Given the exquisite sensitivity of HSCs and proliferating blood cells to radiation, we propose this translocation provided a selective advantage and that protection from sub-lethal radiogenic DNA damage at least partially explains translocation of hematopoietic cells to the bone marrow cavity in terrestrial vertebrates.