On 14 February 2014, there was a release of radiological material at the Waste Isolation Pilot Plant in New Mexico due to improper waste packaging. The resulting chemical reaction released 241Am as airborne contamination in the Waste Isolation Pilot Plant underground repository. This incident caused a small leak through the bypass dampers, creating effluent in an airborne plume of radiological contamination consisting of primarily 241Am. The original ground deposition was determined using validated plume modeling for the precipitation to ensure the release was below regulatory limits. Building upon this data allows for the assessment of long-term, off-site doses downwind of the facility. Using the health physics code HOTSPOT, air source terms were generated across the ground deposition plume in grid format to allow for a detailed analysis of the full scope of the ground deposition plume. The individual squares of the grid, or "kernels" were summed to calculate the dose at different offsite locations from the inhalation pathway. The lifetime integrated total effective dose equivalents (TEDEs) of these areas were all found to be, conservatively, on the order of millisievert or less and thus negligible from a radiobiological perspective. Additionally, further resuspension of this material was accounted for using three of the four different methods available in HOTSPOT. Using conservative assumptions, the wind-adjusted upper bound lifetime doses of all off-site locations were found to be substantially less than the average yearly background dose of around 3.10 mSv and are thus negligible.

A nationwide survey of x-ray imaging practices was conducted during 2014-2015 of a representative sample of US dental offices to gather data regarding patient exam frequencies, indicators for radiation dosimetry and related imaging data, and the data were compared to similar studies conducted during 1993 and 1999.

L-band in vivo electron paramagnetic resonance (EPR) tooth dosimetry is a rapid, non-invasive method for determining the ionizing radiation dose of individuals. Tooth positioning and geometry are the dominant factors influencing EPR intensity. However, the delineation of the geometric parameters and their influence on EPR intensity is still unclear. This induces limitations in the availability of dosimetry for triage and leads to the imperfect consideration of geometric variations affecting EPR intensity. This study aimed to analyze the dosimetric sensitivity variations for each geometric parameter separately. Using finite element analysis, model-based parametric analyses were performed on five geometric parameters: labial enamel thickness (τlab), enamel area (Aen), aspect ratio (RA), horizontal curvature (CH), and vertical curvature (CV). The distributions of these parameters were investigated using micro-CT images from 12 human maxillary central incisors. A quasi-tooth model was proposed to mimic the tooth geometry based on the geometric parameters. The quasi-tooth model well simulated the sensitivity variations observed in the micro-CT derived tooth model. The sensitivity showed a strong linear correlation with the three geometric parameters (τlab, CH, and CV), whereas Aen exhibited a plateau around its average value (75 mm2), and no clear trend was observed for RA. After normalization, τlab, CH, and CV were identified as the dominant contributors to sensitivity variations, whereas Aen and RA had less influence. Considering the correlation between τlab and Aen (r = 0.67, p = 0.017), previous geometric correction methods using Aen may have accounted not only for the direct influence of Aen but also for the indirect correction of τlab. These results demonstrate the principles and limitations of previous geometric correction methods and imply the need for an enhanced method that incorporates multiple parameters for L-band in vivo EPR tooth dosimetry.

The aim of this study was to evaluate the radiological risk to the public due to the use of wood ash as a fertilizer in gardens. Dose assessment is a process in radiation protection that involves determining the amount of radiation to which a person or population has been exposed. It helps to evaluate potential health risks more effectively to ensure that radiation exposure remains within safe limits. Three pathways were considered: inhalation of ash, ingestion of locally produced food fertilized with ash, and direct ingestion of ash. It was assumed that a 0.01 cm, 0.5 cm, or 1-cm-thick layer of ash is used for fertilization per year and that half of the vegetables consumed annually come from one's own garden. The dose assessment for a member of the public older than 17 y using the highest concentrations of 137Cs and 90Sr measured in 27 wood (logs, chips, briquettes, and pellets) ash samples and fertilization with 0.01 cm of ash results in a calculated dose of 3.02 ± 0.24 μSv y-1. The primary exposure pathway is the ingestion of locally produced foods fertilized with wood ash. Besides radionuclides, ash also contains concentrated non-combustible components, including potentially harmful minerals, salts, heavy metals, and organic pollutants. These substances are found in particularly higher concentrations in ash from wood pellets and briquettes than in log and chip ash, so its use as fertilizer---especially in vegetable gardens---should be carefully considered.

The linear no-threshold hypothesis (commonly known as LNT) has received increasing criticism in recent years. LNT assumes that the damaging effects of ionizing radiation, that is, stochastic effects such as cancer and genetic or teratogenic effects, increase linearly with dose and without a lower dose threshold. However, statistically verified data on the relationship between radiation and effects are only obtained for the range above 100 mSv y-1, which is why linear extrapolation downward is carried out for the range of low radiation doses, i.e., below 100 mSv y-1. Today's radiation protection systems are based on this principle. To place radiation protection on a different basis (that is, no longer on the LNT hypothesis), a traffic light model is proposed. It uses natural radiation exposure as a reference but maintains the existing limits and everything in radiation protection that has proven effective. What does change, however, is the lower end of the optimization range, according to the ALARA recommendation. For the justification of today's levels of exceptions, the precautionary principle is applied.

To improve monitoring capabilities, China CDC organized individual monitoring intercomparisons, which provincial health institutions participated in from 2022 to 2024. The irradiation schemes and evaluation criteria were designed in accordance with GBZ 207-2016, "Testing criteria of personnel dosimetry performance for external exposure." The Type II (photon) test specified in the standard was selected as the intercomparison type, with Hp(10) as the target quantity. Each institution submitted 21 dosimeters for participation in the intercomparison exercises. Irradiation schemes with various radiation quality and incident angles were randomly assigned to each participant. Out of 580 Pi values, 82.6% (479) were classified as excellent, and 96.9% (562) met the qualification criteria. Four institutions reported 18 unqualified Pi values. These demonstrate the reliable performance of the dosimetry systems. These intercomparisons helped participants identify system deviations and enabled radiation health administrative departments to grasp the capabilities of each institution, thus strengthening the protection of the occupational health of radiological workers.

External exposure due to secondary photons (predominantly bremsstrahlung) generated from electron source emissions in environmental soil are of concern due to their ability to deposit significant amounts of ionizing energy to organs and tissues within the body. The "condensed history method" employed in many modern Monte Carlo (MC) codes may be used to simulate secondary photon yields (given as photons per beta decay) arising from electron source emissions with relatively few assumptions regarding the secondary photon spatial, energy, and angular dependencies. These yields may in turn be used to derive protection quantities such as secondary photon effective dose rate (DR) and risk coefficients for a variety of idealized external exposure scenarios. Use of the condensed history method is, however, computationally burdensome when simulating idealized external exposure scenarios even with available parallel computing resources. Consequently, use of the method was largely prohibitive for prior environmental dosimetry and risk assessment applications that required innumerable MC simulations for deriving secondary photon protection quantities. A MC method has herein been proposed for estimating secondary photon yields from electron source emissions in environmental soil with the condensed history method in a computationally feasible manner using the Monte Carlo N-Particle version 6.2 (MCNP6.2) radiation transport code. The proposed method was demonstrated with radiation transport models of idealized external exposure scenarios patterned after Federal Guidance Report (FGR) 15, and secondary photon yields determined using the proposed method and a previously adopted analytical method were compared.

The reliability and accuracy of solid-state radiation dosimeters used during clinical procedures using pulsed low-energy x ray is uncertain.

This study examines the range of methodologies used to determine the minimum detectable dose for LiF:Mg,Ti thermoluminescent dosimeters, emphasizing the importance of incorporating uncertainties when assessing variability in dosimeter response. Dosimeters serve various purposes, such as verifying delivered doses, personnel monitoring, environmental surveillance, and research. Each application has unique performance requirements: research may prioritize accuracy and sensitivity at low doses, while routine monitoring favors robustness and efficiency. Dosimetry goals must therefore balance precision, practicality, and resource constraints based on the specific context. This study focuses on four operational factors-dose calibrations, machine vs. oven annealing, heating rate optimization during readout, and glow curve analysis techniques-that shape the variability observed in dosimeter response. Six common methods for calculating the minimum detectable dose were identified from literature and explored in this study. The results demonstrate a wide range of minimum detectable dose values of 10 μGy to 104 μGy, which reflects the combined influence of both uncertainties and the choice of equation. Heating rate was found to have the most significant impact on variance, while annealing methods and analysis techniques had moderate effects, and calibration uncertainties showed smaller implications. Rather than striving solely for the lowest minimum detectable dose, this study features the importance of understanding how these factors influence the minimum detectable dose and applying this knowledge to achieve realistic and application-specific dosimetry goals.

A wide range of particle species, including neutrons, electrons, and photons, will be generated in a terawatt-level (TW) high-power laser facility, which poses considerable challenges for the development of effective radiation shielding solutions. The safety of both facility personnel and the public requires specified design considerations for these shielding systems. The Monte-Carlo code JMCT was employed to simulate and design the shielding structure for the TW facility. We calculated the radiation dose distribution throughout the entire facility for both single-shot and multi-shot operational modes. Our findings indicate that the strategic use of locally thickened shielding walls and mobile shielding measures can effectively mitigate radiation risks in TW-level laser facilities, ensuring that radiation doses within the personnel working area remain within regulatory limits. The results demonstrate that with these shielding strategies in place, the occupational exposure dose in the control room and the clean room can be confined to below 3 mSv y-1, while the public dose remains below 0.1 mSv y-1, considering an experimental frequency of 5 × 106 shots per year for overdense plasma experiments and 1 × 104 shots per year for underdense plasma experiments. The radiation shielding design method and results presented in this paper can serve as a reference for similar devices.

Ionizing radiation technologies play a vital role in agriculture and food processing, contributing to food safety, shelf-life extension, and facilitating international trade of food commodities. Traditionally, 60Co-based gamma irradiation has been used largely for this purpose. However, concerns over the safety of radioactive sources, limited production capacity for 60Co, cost of the radioisotope, and national security concerns have prompted a shift toward safer and sustainable alternatives. Machine source-based electron beam (eBeam) and x-ray technologies have emerged as viable alternatives to 60Co. These technologies are currently being used in pre-harvest agricultural activities and post-harvest practices such as phytosanitary treatment and food pasteurization. Compared to 60Co, eBeam and x-ray technologies offer better economics, greater throughput, and improved dose control without any concerns of radioactive materials or security concerns. Recent advances in the underlying technologies, equipment design, and energy efficiencies have significantly increased the adoption of eBeam and x-ray technologies on a commercial scale worldwide. There are still lingering challenges, such as the initial high cost of investment; unfamiliarity of the core technology among investors, food industry and government decision makers; and regulatory concerns for revalidation. This review paper explores the current global state of science and technology as it relates to ionizing technologies in agriculture and the food industry. The key hurdles in the adoption of eBeam technology have been identified along with practical solutions for a seamless transition toward viable sustainable technologies.

Radioactive isotopes have underpinned radiation medicine and research since their discovery. From early interstitial applications of radium and 137Cs to modern application of 192Ir after-loaders and 125I seeds in brachytherapy, radioisotopes remain the standard of care for several prostate, gynecologic, and head and neck malignancies. However, the continuous emission and high specific activity of sealed sources impose substantial logistical, regulatory, and security burdens. International regulatory agencies therefore advocate minimizing reliance on high-activity sources where feasible. Advances in image-guided, energy-concentrating modalities have yielded clinically mature platforms capable of delivering ablative energy with steep dose gradients and normal-tissue sparing without the need for radioactivity. This review surveys five such modalities: (1) laser interstitial thermal therapy, an MR-thermography-guided laser ablation system; (2) intraoperative radiation therapy, using low-kV x rays or electrons; (3) MRI-guided linear accelerators (MR-LINAC); (4) ultra-high dose rate "FLASH" external-beam therapy; and (5) particle therapy using protons and heavy ions. Collectively, these technologies promise non-radioactive, highly conformal treatment options that leverage diverse radiobiological mechanisms to redefine therapeutic ratios in clinical practice.

Industrial radiography (IR) is a nondestructive testing (NDT) modality used in industries such as oil and gas, automotive, and aerospace. The technique is commonly used to evaluate the structural integrity and uniformity of materials and components, similar to how medical x rays are used to identify breaks in bones. IR employs highly penetrating ionizing radiation (gamma rays, x rays, or neutrons) to produce a visible record of the internal conditions of an object, thus identifying any imperfections or defects. In applications where portability and accessibility are essential, such as the inspection of oil and gas pipelines, radiographic cameras (IR cameras) are commonly used. These devices usually enclose a radioactive isotope and are designed to be portable, making them easy to transport from one location to another. However, their portability combined with the radioactivity of the isotopic sources gives rise to security implications, including the risk of theft or loss followed by some type of malicious use. Due to this security risk, the replacement of gamma-based IR cameras with other non-isotopic alternatives has been an active area of interest. Here we present findings from a recent study led by Sandia National Laboratories aimed at investigating the most effective pathway toward reducing the use of gamma-based IR cameras through their replacement with other non-isotopic alternatives. We begin with an overview of industrial radiography and the industrial radiography market, followed by an analysis of various NDT modalities to identify which would be an adequate alternative to gamma-based IR cameras. Lastly, we discuss lessons learned regarding current trends and market drivers from an industry engagement that was performed as part of this study.

Patients experiencing ascites, the buildup of fluid in the peritoneal cavity, frequently undergo paracentesis to drain fluid from their peritoneal cavity via a peritoneal port. Some patients experiencing ascites may require nuclear medicine procedures to address other medical conditions. Because radiopharmaceuticals circulate throughout a patient's body, they can potentially end up in peritoneal fluid. Handling and disposal of extracted peritoneal fluid containing radioactive material requires appropriate radiation protection practices. This paper details our experience with three patients who underwent paracentesis following 177Lu-DOTATATE treatment and had megabecquerel quantities of 177Lu present in the extracted fluid. A simple method for quantification of peritoneal fluid 177Lu activity concentration, recommendations for managing 177Lu-DOTATATE patients requiring paracentesis, and proper disposal of radioactive peritoneal fluid containing is also discussed.Health Phys.

Internal dosimetry is a part of radiation safety for patients and radiation workers in nuclear medicine procedures. This study retrospectively determined the effective dose for oncology patients undergoing PET/CT scans by using widely used computer codes, and the results were compared with each other and literature. The study focused on the radiopharmaceuticals 18F-FDG (n = 220) and 68Ga-PSMA (n = 85), administered to 305 patients for cancer imaging at Yeditepe University Kosuyolu Hospital's nuclear medicine department. PET dose was calculated using OLINDA/EXM, IDAC-Dose 1.0 and IDAC-Dose 2.1 programs while ImPACT software was used to determine the effective dose from the CT scan. All effective doses were derived in accordance with ICRP 60 and ICRP 103 tissue weighting factors. PET effective doses from highest to lowest were calculated with OLINDA/EXM, IDAC-Dose 1.0, IDAC-Dose 2.1 (ICRP 60) and IDAC-Dose 2.1 (ICRP 103) as 9.96, 9.07, 7.01, 6.28 mSv respectively for 18F-FDG. The highest PET effective dose was also calculated with OLINDA/EXM software as 3.65 mSv for 68Ga-PSMA. For the total effective dose in PET/CT scans, CT contributed about 92% for 68Ga-PSMA protocol and 75% for 18F-FDG protocol.Key words: effective dose; internal dosimetry; 18F-FDG; 68Ga-PSMA; OLINDA/EXM; IDAC Dose 2.1; IDAC-Dose 1.0; PET/CT.

The present research is proposing a mathematical method to calculate the dose absorbed by a moving object in a non-uniform radiation field. In such conditions, the dose is the function of time and position of the object relative to the radiation source. In this regard, a 60Co irradiation processing facility has been investigated in which, the non-uniform planar source of gamma-rays, irradiates the boxes moving which move around the source. In irradiation facilities, addition to the strength of 60Co source, the speed of boxes is in great importance in obtaining the desired total dose to the boxes, however in most cases, the speed has been determined traditionally and by try-and-error method after the construction and installation of the radiation source. In this research, the speed of boxes (conveyor's speed) was determined so that, the desired dose has been delivered to each box. The dose profile inside of the boxes has been calculated based on the different positions from the rack. The presented calculations aim to optimize the detailed design of the mentioned facility and for the more efficient performance because, it helps to make the faster radiation processing in a smaller place. The calculations have been conducted using MCNPX.2.7 and Geant4.10.5 Monte Carlo tools in order to obtain most reliable results.Health Phys. 000(0):000-000; 2025.

This study investigates the impact of heating rates, ranging from 1 °C s⁻1 to 20 °C s⁻1, on the precision of integrated peak counts determined using various thermoluminescent dosimeter materials. Lower heating rates influence precision due to prolonged integration of signal noise, while higher heating rates affect precision by pronounced thermal quenching effects. Using time-temperature profiles constructed with a linear heating ramp and a constant hold at maximum temperature, a range of heating rates was evaluated to identify an optimal condition that minimizes variance in integrated peak counts resulting from these effects. In addition, kinetic parameters of glow peaks were determined through peak deconvolution of each glow curve obtained and analyzed as a function of heating rate, with observed trends fit to appropriate models. These results were then compared to trapping parameters - namely the activation energy and frequency factor - independently extracted using the variable heating rate method to assess consistency across techniques. The results indicate that peak temperatures and intensities exhibit strong exponential dependence on heating rate, while activation energies and frequency factors show weak linear correlations. Trapping parameters obtained using the variable heating rate method fell within the range of values derived from peak deconvolution, supporting consistency between the two approaches. An optimal heating rate of 4 °C s⁻1 was identified for minimizing variance in integrated peak counts across all dosimeter types tested. Both noise and thermal effects were shown to influence measurement variance, with thermal quenching effects having a more pronounced impact at higher heating rates. Additional factors affecting precision included dosimeter material, glow peak temperature, and overall glow curve complexity. These findings enhance the understanding of thermoluminescent dosimeter behavior and highlight the importance of optimizing the heating rate for improved measurement reliability.

Following the reduction in the occupational eye lens dose limit by the International Commission on Radiological Protection (ICRP), a physical phantom was developed to enable lens dose monitoring in complex radiation environments. The design is based on a validated eye model used to derive lens dose conversion coefficients. After evaluating various materials using Monte Carlo simulations, polymethyl methacrylate (PMMA) was selected for its ease of manufacturing and decontamination. The phantom's dose conversion coefficients were calculated for a range of photon energies and irradiation angles. Lens doses were measured using thermoluminescent dosimeter (TLD) chips embedded in the phantom and exposed to a 137Cs reference field. Measurements were compared with simulation results, demonstrating good agreement. This newly developed PMMA phantom offers a practical solution for evaluating lens dose in non-uniform radiation fields such as those found in nuclear power plants.

For the calculation of fractional deposition of radioactive aerosols, the deposition model in ICRP Publication 130 has been widely used. However, the deposition model is based on the anatomical and physiological characteristics of Caucasians. Since physiology and anatomical parameters of Chinese differ from those of Caucasians, this difference can affect the applicability of depositional models to Chinese people. ICRP suggests that the corresponding parameters can be replaced when the parameters of concerned people are known. Therefore, this paper investigates the physiological and anatomical parameters of Chinese people and establishes a respiratory deposition model applicable to Chinese people. It is found that the dependence of fractional deposition on aerosol particle size on Chinese people is qualitatively similar to that in Caucasian people. However, the value of fractional deposition is quantitatively different. When the AMAD (activity median aerodynamic diameter) is 1 μm (public exposure), the ratio of fractional deposition between Chinese and Caucasian light workers could reach up to 1.22 in the AI region, and the ratios of fractional deposition in other regions also ranged from 0.87-0.93; when the AMAD is 5 μm (occupational exposure), the ratio of fractional deposition between Chinese and Caucasian light workers could reach up to 1.35 in the AI region, and the ratios of fractional deposition in other regions also ranged from 0.95-1.30. The fractional deposition is used as input to biokinetic models to simulate the transport of radionuclides through the body after inhalation and ultimately impacts the dose conversion factor calculations.

Fluoroscopic C-arm units are used routinely in surgical procedures, but they pose potential radiation hazards, particularly in terms of scatter and tertiary exposure to healthcare providers, which can lead to long-term health effects. This study investigates the level of scatter radiation emitted by the C-arm during Dynamic Hip Screw (DHS) surgery across four general hospitals. A water phantom was placed in the center of the operating table, simulating an average patient. OSL dosimeters were placed at standardized distances and heights around all sides of the phantom to measure scatter radiation exposure. The OSL dosimeter readings recorded consistent scatter radiation levels for all positions (A, B, C, D, and E) and heights (0.5 m, 1.0 m, and 2.0 m). Exposure levels ranged from 0.06 to 0.09 mSv, with negligible variations based on distance from the phantom. One-way ANOVA results showed differences in scatter radiation exposure between hospitals (F-statistic = 2.68, p = 0.044). Despite inter-hospital variations, exposure levels were below international safety levels. Results indicate that healthcare workers are unlikely to surpass the yearly dose levels of radiation during normal use. Routine exposure highlights the necessity for proper safety precautions, such as lead aprons, shielding barriers, and room layout optimization. Future studies should take C-arm shielding and positioning into account to continue reducing exposure to scatter radiation. Further research is recommended to evaluate long-term cumulative exposure and improve radiation safety protocols.

In sound card-based gamma spectroscopy, a computer sound card serves as the multichannel analyzer in a spectroscopic system with a lower price point and more compact form factor than many traditional systems. A mobile system for radiation measurements, named RadMap, was created to investigate the potential of using sound card spectroscopy in a handheld, mobile radiation measurement and spectroscopic device. RadMap was designed using commercially available parts, including a sound card spectrometer, and is compatible with most photomultiplier tube scintillators for spectroscopic applications or Geiger-Mueller detectors for non-spectroscopic usage. Measurements of 137Cs, 22Na, 54Mn, and 60Co were made using RadMap and two professional desktop gamma spectroscopy systems to characterize RadMap's spectroscopic capabilities relative to those commercial devices. Radiation surveys were created of a 14,000 m2 outdoor space on a college campus using RadMap and other commercially available survey meters for comparison. The results of these experiments suggest that RadMap can provide high quality spectroscopic information and mapable survey information in a device with a favorable price point while enabling easy user modifications. Exact details regarding the components used and their functions are provided to facilitate the creation or further development of a similar system by any interested party.