Radiation protection dosimetry最新文献

To assess the current status of radiation protection in Changzhou veterinary hospitals. Questionnaires were used to survey the veterinary hospitals and their radiation workers, questions included veterinary hospitals' basic information, location, type of X-ray diagnostic equipment, and personal information, status survey, the radiation cognition of the radiation workers. In search of veritable data for the estimation of occupational doses, an AT1123 radiation survey dosemeter was used to simulate the measurement of the ambient dose equivalents around the head and neck of a radiation worker operating in the imaging room. RaySafe RF was used to measure the air kerma at the center of the irradiation field and 0.5 cm from it. RaySafe RF and related phantoms were used for performance tests of X-ray diagnostic equipment. A total of 118 veterinary hospitals, 118 radiation workers, and 119 X-ray diagnostic equipment were surveyed. Among the 119 X-ray diagnostic equipment, 118 were DR (Digital Radiography) for veterinary practice, and 1 was a general-purpose CT scanner. The 118DRs cover 31 brands (manufacturers), the top six brands of DRs accounted for 68% of the total. A portion of the veterinary hospitals did not fully consider radiological protection in site selection (most veterinary hospitals were located near shops or residential areas), imaging room location (only 53 X-ray diagnostic devices are set on the first floor), and imaging room shielding. One hundred and seventeen (98.3%) X-ray diagnostic equipment needs to be operated while the radiation workers stay in the imaging room. Individual monitoring of occupational external exposure was carried out in 117 (99.2%) veterinary hospitals, and 59 (50.0%) did not carry out health surveillance for radiation workers. Twenty three (19.5%) veterinary hospitals placed Thermoluminescent Dosimeter (TLDs) in the imaging room or even next to the X-ray tube. The vast majority of radiation workers manually restrained pets (93.2%) and the majority (84.7%) of radiation workers refused to wear lead gloves during restraints, resulting in occasional exposure of their hands to the primary beam. The performance tests of X-ray diagnostic equipment of six DRs found that DRs of four (66.6%) brands had unqualified indexes, and the main unqualified indexes were the linearity of tube output of two DRs (33.3%) and alignment of X-ray field of three DRs (50.0%). The air kerma in the irradiation field of DRs ranged from 122.3 to 410.4 uGy, and there were obvious differences between the air kerma in the irradiation field and out of it (Z = -5.125， P <.001). The ambient dose equivalents around the head and neck of animal restrainers ranged from 22 to 182 nSv. The site selection of the veterinary hospitals, and the placement of the imaging room are not optimized because of the lack of occupational hazard assessment, the routine performance tests of X-ray diagnostic equipment are not carried out, and the occupational health ex

This study determined weight-based median radiation dose levels or typical values as defined by the International Commission on Radiological Protection of pediatric cardiac computed tomography angiography (CTA) in a tertiary hospital. A total of 211 cardiac CTA studies from 194 children (<15 years old) were retrospectively analyzed. The study examinations were organized into categorized base on body weight ranges. The typical values for CTDIvol(mGy) and DLP(mGy.cm) were respectively determined for each weight band as follows: <5 kg(n = 42): 1.02,12.16; 5 ≤ 15 kg(n = 57): 1.42, 25.0; 15 ≤ 30 kg(n = 53): 2.15, 40.94; 30 ≤ 50 kg(n = 26): 3.80, 100.04; and 50 ≤ 80 kg(n = 3): 8.06, 212.23. The overall median (interquartile range) for each CT dose parameter were as follows: E = 1.80 (1.16-2.83) mSv, SSDEDw = 3.23 (2.54-4.78) mGy, SSDEAP = 3.17 (2.51-4.68) mGy, SSDELAT = 3.18 (2.54-4.50) mGy, SSDEAP + LAT = 3.25 (2.60-4.57) mGy, and SSDEEff = 3.21 (2.57-4.55) mGy. Further research is needed to develop local, regional, and national weight-based lifetime attributable risks for cardiac CTA in children.

An analysis compared the occupational radiation doses received by Nuclear Medicine Technologist (NMT) and radiography students during their clinical training at an Australian University from 2017 to 2020. Utilising Optically Stimulated Luminescence dosemeters to measure the personal dose equivalent, the retrospective cohort included students with dose readings above 100 μSv per monitoring period. Of the total number of students monitored, ~68% received doses below the minimum reportable threshold of 100 μSv per monitoring period, suggesting that most students had minimal exposure during their placements. A chi-square test revealed a significant difference between NMT and radiography students in the proportion of doses below this threshold (Hp(10): χ2(1, N = 1367) = 168.24, P < .001; Hp(0.07): χ2(1, N = 1367) = 139.27, P < .001). Analysing doses above this threshold revealed that NMT students had significantly higher median radiation doses than radiography students, with median Hp(10) doses of 161 μSv versus 130 μSv, respectively (P < .001). Year-to-year analysis indicated that NMT student doses remained stable over the study period, while radiography student doses varied significantly. Comparison with hospital staff doses showed that NMT students received significantly lower doses than professional NMTs (P < .001), whereas radiography students received higher doses than professional radiographers (P < .001). After limiting hospital staff doses to include those only above 100 μSv in a reporting period, radiography students still received higher doses than professional radiographers. The elevated exposure among NMT students compared to radiography students however, emphasizes the need for enhanced radiation protection strategies in nuclear medicine education, emphasising specialized training and regular dose assessments to ensure student safety without compromising educational quality.

The study investigated the maximum range of 90Sr-90Y sources in different shielding materials and assessed β-directional dose equivalent rates and γ ambient dose equivalent rates across varying thicknesses of shielding. Results indicated: (1) Significant differences in 90Sr-90Y source ranges among materials, with the shortest β-ray range observed in tungsten alloy (0.00 to 0.50 mm) and high-purity lead (0.5 to 1.0 mm). (2) Generally, there was good agreement between experimental and simulation data, except at a thickness of 0.5 mm for high-purity lead, where a deviation of 51.4 per cent in β-directional dose rates was observed, likely due to errors in the lead cross-section data. (3) Comparative analysis demonstrated that combinations such as "304 + W" or "304 + Pb" offer enhanced shielding effectiveness against 90Sr-90Y sources. This study provides valuable insights for selecting β-radiation shielding materials and structures.

In medical facilities, pre-shielding calculations are essential when introducing new X-ray equipment to protect the staff from radiation. For computed tomography (CT), the dose length product (DLP) method is commonly used for shielding calculations. This method allows the evaluation of the dose at any wall position. This study proposed a cost-effective design for CT room shielding, adjusting the material thickness based on the operator's exposure and the room's environment. Scattered radiation was measured using an optically stimulated luminescence dosemeter. The calculated values were 2.0 to 7.5 times higher than the measured values inside the CT room, confirming the accuracy of the DLP method in estimating the actual dose. No scattered radiation was detected outside the CT room. This study demonstrates that the DLP method enables pre-installation shielding calculations that balance cost and safety.

A compact, portable, and tabletop thyroid monitor has been developed for in vivo measurement of 131I activity in the thyroid. This system is designed for use in laboratory settings for monitoring of occupational workers and is also suitable for onsite deployment by radiological emergency response teams during radiation emergency situations for thyroidal measurement of the general public. The monitor incorporates a 51 mm diameter × 51 mm-thick NaI(Tl) scintillation detector coupled with a standalone 1 K multi-channel analyzer, housed within a shielded collimator. The system allows for variable counting geometries, accommodating diverse measurement requirements. Key design elements include a vertical movement system, a chin rest, a calibrated neck-to-collimator distance scale, and an Light Emitting Diode-based alignment indicator to ensure precise positioning of the thyroid relative to the detector. A specialized software has been developed for the quantification of thyroidal 131I activity, intake estimation, and committed effective dose calculation. Under normal radiation background conditions (~70 nSv/h), the system achieves a minimum detectable activity of 60 Bq with a 5-min counting time. The monitor is capable of accurately assessing thyroid equivalent doses below 50 mSv, even under conditions of elevated environmental radiation following radiation emergency situations. This system enhances rapid and in situ thyroidal 131I monitoring, supporting radiation protection efforts in both routine monitoring and emergency response scenarios.

We conducted an online survey of 1953 members of the general population (valid response rate: 65.1%) and 384 radiological technologists (valid response rate: 100%) to examine the relationship between radiation knowledge and concerns. The mean knowledge score (maximum: 50) was 28.7 in the general population and 40.2 among radiological technologists. The mean concern scores (maximum: 50) were 25.0 and 17.1, respectively. Both scores differed significantly between the groups (Mann-Whitney U test, P < .01). In the general population, the relationship between knowledge and concern scores varied according to age. In those aged < 30 years, the correlation was weak (R, -0.411 to -0.412), whereas in those aged ≥ 30 years, it was stronger (R, -0.541 to -0.546), suggesting that knowledge reduces concerns. No significant age-based differences were observed among the technologists. These findings suggest that increasing knowledge about radiation may help alleviate concerns.

Exposure to thorium-bearing dust in industries handling and processing monazite and other minerals can pose radiological risks to workers. This study aimed to reassess historical faecal bioassay data collected over 10 d from two monazite plant workers using updated biokinetic and dosimetric models. Another objective was to evaluate the feasibility of faecal thorium bioassay for contemporary operations involving naturally occurring radioactive materials (NORM). The retrospective analysis found that the bioassay-derived thorium intakes were significantly higher than those estimated via personal air sampling. The effective dose estimates for the two workers were similar and ranged from 0.95 to 2.40 mSv over the 5-d exposure period, depending on the worker's assumed mode of breathing. The study confirmed that faecal thorium bioassay remains a viable tool for monitoring workers exposed to insoluble thorium dust, but the timing of sample collection, individual physiology, and background dietary intake of NORM must be considered.

In interventional cardiology, occupational radiation exposure for medical personnel can reach high levels, underscoring the critical need for effective radiation protection and monitoring methods. This study employs machine learning algorithms to estimate radiation doses received by personnel within a virtual 3D angiography room designed to reflect realistic clinical settings. Monte Carlo simulations generated radiation data across various scenarios, accounting for personnel positions, radiation source distance, and exposure angles typical in angiography. The simulation data were used to train five machine-learning algorithms (Gradient Boosting, K-nearest neighbors, Random Forest, Linear Regression, and Decision Tree). Key findings showed that machine learning models, particularly Gradient Boosting, could effectively predict dose levels by utilizing spatial and operational parameters without requiring physical dosemeter. This study provides a framework that could streamline radiation monitoring practices, making dose assessments more accessible and efficient for routine use in clinical environments.

Radiation exposure is a primary concern during interventional cardiology procedures. This study evaluates the impact on patient and operator radiation exposure of implementing modern shielding, innovative imaging technologies and optimized protocols, combined with staff education. Radiation exposure data during coronary angiography (CA) and percutaneous coronary intervention (PCI) procedures were analyzed in three cohorts: use of historical imaging protocols and conventional operator shielding (P0); introduction of a suspended operator radiation protection system (P1); implementation of innovative imaging chain and optimized protocols (P2). Patient radiation levels between P0 and P2 were significantly reduced by up to 44% for CA procedures and up to 74% for PCI procedures. Operator doses showed a reduction of 86% and 93% for CA and PCI, respectively. Compared to literature, our patient dose levels were among the lowest, with values well below current European dose reference levels.