Radiation protection dosimetry最新文献

As interest in 67Ho increases, the need to accurately calculate the production yields will also increase; this study aims to evaluate theoretically the neutron capture cross-section for the neutron-induced reactions 165Ho(n,γ)166Ho and 166mHo(n,γ)167Ho by using the TALYS 1.96/2.0 nuclear code at 25 keV energy. The obtained values are 1.42 b and 2.60 b respectively. The theoretical values obtained are compared with the experimental data extracted from the EXFOR database and the theoretical libraries TENDEL-2023 and JENDL-5 in order to test the validity of the TALYS nuclear code and to seek agreement between the obtained and the experimental values.

Radiographic exposure factor selection impacts image quality and radiation dose. This study examined the professionals responsible for conducting X-ray examinations and their training in Ireland. An online survey was distributed to all practices registered with the Veterinary Council of Ireland. Data were collected on demographics, X-ray equipment, methods of exposure factor selection, confidence in adjustments, and knowledge of detector dose indicators. A total of 120 responses were received. Most clinics use digital systems and rely on technique charts. Many respondents showed limited understanding of detector dose indicators, with 40% reporting poor knowledge and nearly half unaware of their system's capabilities. Exposure factors were rarely adjusted, raising concerns about dose creep. Confidence was higher among less experienced staff. No strong association was found between post-qualification training and confidence. Findings highlight the need for improved training, continuous professional development, and guidelines to optimize practice.

We simulated the mm-wave exposure of a real 60 GHz communication module and validated it using near-field measurements in terms of the incident power density. Next, we numerically evaluated the absorbed power density in a layered tissue model using the finite-difference time-domain technique. The worst-case and realistic exposures were compared with the latest guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and of the Institute of Electrical and Electronics Engineers (IEEE). The worst-case exposure complied with the exposure guidelines for a distance larger than 14.5 mm. Realistic exposure is application dependent and exceeded the limits specified by exposure guidelines for data-intensive applications with duty cycle of 90% at distances smaller than 10.6 mm.

A γ-ray calibration field using a sealed 133Ba source for photon energy in the 300-400 keV range was established at the Japan Atomic Energy Agency to evaluate radiation protection devices under low dose rate conditions. To suppress low-energy γ-ray components, a 2-mm lead filter was applied. The photon fluence spectrum was measured using a CdTe spectrometer and an unfolding method, yielding a spectrum with a mean energy of 321 keV. Reference air kerma rates were determined using ionization chambers calibrated in a 137Cs field, with energy correction factors applied. Spectrometry using a CeBr₃ scintillation spectrometer combined with the G(E) function method was employed to validate these corrections. Spectrum-averaged conversion coefficients were derived from the measured spectrum, indicating equivalence to the N-400 radiation quality. This field provided air kerma rates from 0.22 to 2.13 μGy h-1, suitable for testing devices used in environmental monitoring and nuclear emergency response.

This study investigated the seasonal variations of indoor radon concentrations in parts of cities across different climate zones of China. Using solid state nuclear track detectors (SSNTDs), radon measurements were conducted over a 12-month period in 171 dwellings located in 15 provincial capital cities. The annual average indoor radon concentration was 81 Bq m-3, with the highest mean level recorded in the Severe Cold Area (99 Bq m-3) and the lowest in the Hot Summer Warm Winter Area (52 Bq m-3). A consistent seasonal pattern was observed across all zones, characterized by elevated concentrations in autumn and winter and lower levels in spring and summer. The mean winter-to-summer concentration ratio was 1.68, indicating a declining trend compared to earlier data from 1994 in China. This trend may be attributed to changes in ventilation practices associated with the widespread adoption of air conditioning. Seasonal correction factors were determined for different climate zones, ranging from 0.80 to 1.43. This study highlights the seasonal fluctuations of indoor radon and the necessity of applying appropriate correction factors when estimating annual average radon concentrations based on short-term measurements to reduce assessment bias. The findings provide critical data and a methodological foundation for accurately assessing and seasonally correcting indoor radon concentrations under diverse climatic conditions in China.

This study aims to evaluate the uranium concentration as an indicator of internal exposure to assess its potential biological effects, including DNA fragmentation and oxidative stress. Blood samples were collected from 80 individuals (40 residents and 40 from the control group) in Jisr Diyala district, Iraq, for uranium measurements. DNA fragmentation and malondialdehyde (MDA) concentration were estimated using the comet assay and MDA assay, respectively. The uranium concentration in the blood was significantly higher (605.90 ng l-1) in the residents compared to that in the control group (367.04 ng l-1). DNA fragmentation showed a 1.8-fold longer DNA tail, 2.4-fold larger tail area, 2-fold higher %DNA in the tail, and 3.3-fold higher tail moment in the resident group than in the control group. The mean MDA concentration was higher in the resident group (1.250) than in the control group (0.698). A positive correlation was observed between uranium concentration, DNA tail length, DNA tail moment, and MDA concentration. Increased uranium levels underline the importance of studying the associated health risks and biological effects.

The aim of this study was to assess the impact of a state-of-the-art 32 cm axial field-of-view GE Omni Legend PET/CT system on administered activity and image quality, and to update Diagnostic Reference Levels (DRLs). System performance was evaluated using NEMA NU 2-2018 measurements and EARL2 accreditation tests. A comparison with the previous 5-ring GE Discovery IQ scanner was performed to analyze the administered activity, scan duration and image quality with and without Artificial Intelligence driven reconstruction. A retrospective analysis of standard-sized adult examinations was conducted to derive updated DRLs values. Omni Legend demonstrated improved sensitivity and Noise Equivalent Count Rate, enabling up to 60% reduction in injected activity while maintaining or improving image quality. Deep learning reconstruction enhanced image quality, particularly at lower administered activities. The DRLs were lower than the national and international reference levels, supporting dose optimization in clinical practice.

Monitoring radiation doses is critical for safety in nuclear medicine (NM) departments. This study assessed personal and ambient radiation doses during routine NM procedures and compliance with International Commission on Radiological Protection (ICRP) limits at the new NM department of Abu Ali Sina Hospital, Shiraz, Iran. Between March and April 2024, 500 procedures involving 99mTc and 131I were performed. Personal dose equivalents Hp(10), Hp(3), and Hp(0.07) were measured for staff using calibrated TLD-100 dosemeters. Ambient doses were monitored across the department. Measured doses included 11.19 mSv (fingers), 14.62 mSv (hands), 0.11 mSv (whole body), and 0.03 mSv (eye lens), with Technologist 2 showing the highest hand dose. Ambient monitoring showed the highest dose rate (1.19 μSv/h) in the waiting area near the hot lab, mainly from post-injection patients. While all doses remained within ICRP limits, the findings indicate the need for improved shielding and optimized workflow to minimize extremity and environmental exposure.

In recent years, more and more electronics have been exposed to the mixed radiation field. The radiation resistance of electronics has been paid more and more attention to and the China Spallation Neutron Source (CSNS) linac tunnel provides a natural mixed radiation field. One of the radiation hotspots induced by beam loss when the CSNS linac regularly operates is the debuncher component in the beamline. The radiation level around the debuncher was measured by dose monitors and simulated by the FLUKA code simultaneously. The results of measurement and simulation are consistent, which means that the model simulated by the FLUKA code is consistent with the actual situation. The energy spectrum of the mixed radiation field at CSNS was first simulated by the FLUKA code. The mixed radiation field is composed of charged and neutral hadrons (protons and neutrons), photons, and electrons over a range of energies. This radiation field is suitable for the radiation damage effect tests of electronic components operating in the mixed radiation environment, especially for the electronic components used in the accelerator tunnel.