Comparison of radiation-shielding curtains for endoscopic retrograde cholangiopancreatography staff.

Occupational radiation exposure to the eye lens of medical staff during endoscopic retrograde cholangiopancreatography (ERCP) should be kept low so as not to exceed annual dose limits. Dose should be low to avoid tissue reactions and minimizing stochastic effects. It is known that the head and neck of the staff are exposed to more scattered radiation in an over-couch tube system than in a C-arm system (under-couch tube). However, this is only true when radiation-shielding curtains are not used. This study aimed to compare the protection radiation to the occupationally exposed worker between a lead curtain mounted on a C-arm system and an ERCP-specific lead curtain mounted on an over-couch tube system. A phantom study simulating a typical setting for ERCP procedures was conducted, and the scattered radiation dose at four staff positions were measured. It was found that scattered radiation doses were higher in the C-arm with a lead curtain than in the over-couch tube with an ERCP-specific lead curtain at all positions measured in this study. It was concluded that the over-couch tube system with an ERCP-specific lead curtain would reduce the staff eye dose by less than one-third compared to the C-arm system with a lead curtain. For the C-arm system, it is necessary to consider more effective radiation protection measures for the upper body of the staff, such as a ceiling-suspended lead screen or another novel shielding that do not interfere with procedures.

Virtual reality training for radiation safety in cardiac catheterization laboratories - an integrated study.

The advent of fluoroscopically guided cardiology procedures has greatly improved patient outcomes but has also increased occupational radiation exposure for healthcare professionals, leading to adverse health effects such as radiation-induced cataracts, alopecia, and cancer. This emphasizes the need for effective radiation safety training. Traditional training methods, often based on passive learning, fail to simulate the dynamic catheterization laboratory environment adequately. Virtual Reality (VR) offers a promising alternative by providing immersive, interactive experiences that mimic real-world scenarios without the risks of actual radiation exposure. Our study aims to assess the effectiveness of VR-based radiation safety training compared to traditional methods. We conducted a prospective cohort study involving 48 healthcare professionals in a catheterization lab setting. Participants underwent a 1-hour self-directed VR training session using Virtual Medical Coaching's RadSafe VR software, which simulates real-world clinical scenarios. Pre- and post-intervention radiation dose levels were measured using personal dosimeters at the eye, chest, and pelvis. Knowledge and skills were assessed through tests, and feedback was gathered through surveys and interviews. Statistical analysis revealed significant reductions in radiation exposure across all professional groups after VR training. For cardiologists, the eye dose dropped by 21.88% (from 2.88 mSv to 2.25 mSv), the chest dose decreased by 21.65% (from 4.11 mSv to 3.22 mSv), and the pelvis dose went down by 21.84% (from 2.06 mSv to 1.61 mSv). Perioperative nurses experienced similar reductions, with eye doses decreasing by 14.74% (from 1.56 mSv to 1.33 mSv), chest doses by 26.92% (from 2.6 mSv to 1.9 mSv), and pelvis doses by 26.92% (from 1.3 mSv to 0.95 mSv). Radiographers saw their eye doses reduced by 18.95% (from 0.95 mSv to 0.77 mSv), chest doses by 42.11% (from 1.9 mSv to 1.1 mSv), and pelvis doses by 27.63% (from 0.76 mSv to 0.55 mSv).Participants reported enhanced engagement, improved understanding of radiation safety, and a preference for VR over traditional methods. A cost analysis also demonstrated the economic advantages of VR training, with significant savings in staff time and rental costs compared to traditional methods. Our findings suggest that VR is a highly effective and cost-efficient training tool for radiation safety in healthcare, offering significant benefits over traditional training approaches.

Radiation exposure to patients undergoing percutaneous transhepatic cholangiography and endoscopic retrograde cholangiography: an advanced phantom study.

Fluoroscopic examinations like Endoscopic Retrograde Cholangiopancreatography (ERCP) and Percutaneous Transhepatic Cholangiography (PTC) are fundamental in diagnosing and treating hepatobiliary diseases. However, these procedures expose patients to significant radiation, highlighting the need for a detailed assessment of the radiation doses received by critical organs. The study's primary objective is to determine the experimental doses received by critical organs in patients undergoing these procedures. This study utilized an Alderson RANDO phantom outfitted with Thermoluminescent Dosemeters (TLDs) to experimentally measure the radiation doses received by various organs during ERCP and PTC procedures. This method provided direct and accurate data on organ-specific radiation exposure, contrasting with the traditional approach of relying on theoretical simulations. The analysis revealed that PTC generally results in higher radiation doses to organs compared to ERCP. Critical organs, such as the thyroid, spleen, liver, pancreas, ovaries, and uterus, were exposed to varying levels of radiation, with the thyroid and spleen receiving particularly high doses in PTC. The study also demonstrated that the per-minute radiation exposure was consistently higher in PTC across all examined organs. The study's findings underscore the significant radiation exposure associated with ERCP and PTC, with PTC posing a greater risk. Understanding these exposure levels is crucial for clinical decision-making, particularly when considering patients' pre-existing conditions and sensitivity to radiation. The study highlights the need for clinicians to carefully weigh the benefits of ERCP and PTC against the potential radiological risks. It suggests a preference for ERCP in situations where radiation exposure needs to be minimized. Furthermore, the findings advocate for ongoing advancements in medical imaging techniques to reduce radiation exposure, emphasizing the importance of patient safety in fluoroscopic examinations. This research contributes significantly to informed clinical decision-making, ensuring that the selection of diagnostic and therapeutic procedures aligns with the best interest of patient health and safety.

Assessment of foetal dose and occupational exposure for pregnant workers in nuclear medicine using the Taiwanese pregnancy phantom.

For pregnant workers in nuclear medicine, radiation doses can pose a risk to their foetus. However, foetal radiation doses cannot be measured directly. In this study, a method of estimating foetal radiation doses was developed through simulations and measurements of phantoms of pregnant women in the three trimesters. The uterus and abdominal surface doses for monoenergetic photons (137Cs) and medical diagnostic X-rays were measured, and uterine dose conversion coefficients (UDCCs) were calculated. The accuracy of the UDCC estimates were validated for measurements from thermoluminescent dosemeter (TLD) chips and TLD badges on the abdomen or chest. The foetal effective dose could be estimated using TLD chips and TLD badges on the abdomen or chest, or through literature estimation method. The proposed method can be used to easily and accurately estimate foetal effective doses from chest-worn TLD badges, ensuring accurate estimation in the early stage of pregnancy when a worker may not yet be wearing an abdominal badge. A flowchart for applying the UDCC method to approximate a foetal dose is also provided to ensure that total doses remain below the maximum of 1 mSv recommended in the International Commission on Radiological Protection 103 guidelines.

Radiological assessment of radon in groundwater of the northernmost Kashmir Basin, northwestern Himalaya.

This study investigates the radon concentration in groundwater in Kupwara, the northernmost district of the Kashmir valley. It further assesses the annual effective dose experienced by the district's diverse population-infants, children, and adults-attributable to both inhalation of airborne radon released from drinking water and direct ingestion. In addition to this, the calculation of gamma dose rate is also carried out at each of the sampling site of radon. A portable radon-thoron monitor and a portable gamma radiation detector were respectively employed to estimate the activity concentration of radon in water samples and to measure the gamma dose rate. The radon concentration was found to exhibit variability from a minimum of 2.9 BqL-1 to a maximum of 197.2 BqL-1, with a mean of 26.3 BqL-1 and a standard deviation of 23.3 BqL-1. From a total of 85 samples, 10.6% of the samples had radon activity concentrations exceeding the permissible limits of 40 BqL-1 set by the United Nations Scientific Committee on Effects of Atomic Radiations as reported by UNSCEAR (Sources and effects of ionizing radiation, 2008) and only 1.2% of the samples have radon activity concentration exceeding the permissible limits of 100 BqL-1 set by the World Health Organization as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The mean of the annual effective dose due to inhalation for all age groups as well as the annual ingestion dose for infants and children, surpasses the World Health Organization's limit of 100 µSv y-1 as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The observed gamma radiation dose rate in the vicinity of groundwater radon sites ranged from a minimum of 138 nSv h-1 to a maximum of 250 nSv h-1. The data indicated no significant correlation between the dose rate of gamma radiation and the radon levels in the groundwater. Radon concentration of potable water in the study area presents a non-negligible exposure pathway for residents. Therefore, the judicious application of established radon mitigation techniques is pivotal to minimize public health vulnerabilities.

Impact of Cosmic Rays on Radiation Exposures and Scientific Activities at the Atacama Large Millimeter/Submillimeter Array (ALMA) Sites.

This study delves into the investigation of cosmic-ray radiation exposure levels for workers and their impact on the signal correlation subsystems at the Atacama Large Millimeter/submillimeter Array (ALMA) observatory sites. The analysis presents a detailed examination of secondary cosmic ray spectra and flux at the ALMA sites, encompassing the operational period from 2010 to the present day, with a particular focus on the consequences of extreme solar flares. In terms of radiation exposure for ALMA employees, the annual exposure at the highest site (AOS) reaches approximately 4.8 mSv. This value exceeds the exposure level of a typical nuclear fuel cycle worker or those working at high-altitude Antarctica stations. The exposure is approximately 2.7 times lower at the ALMA Operations Support Facility (OSF). Furthermore, the additional ambient dose equivalent resulting from solar events, while low for events similar to those observed since the 1950s, can reach up to approximately 1 mSv when considering more ancient solar events based on environmental archives. Our analysis includes radiation effects measurements in the Baseline Correlator at the AOS and, more generally, underscores the significance of employing accurate modeling and simulation techniques to assess the effects of galactic cosmic rays and extreme solar events on the integrated circuits utilized or planned in the ALMA correlation subsystem.

Reduction of detection limits in monitoring of internal exposures by a combined evaluation of emissions and spectra.

Routine monitoring of internal exposures requires the detection of effective doses of at most 1 mSv per calendar year. For some radionuclides, this requirement cannot be satisfied by a conventional evaluation of the spectra that are gained in alpha or gamma spectrometry. However, since several measurements are conducted per calendar year on a regular basis, a combined evaluation of measurements, i.e. the evaluation of sum spectra, is possible. Additionally, radionuclides that feature several emissions of alpha or gamma radiation allow a combined evaluation of their emissions. Both methods can lead to significantly smaller detection limits as compared to a separate evaluation of spectra in many cases. However, the variation of parameters that influence the evaluation such as the measurement efficiency, abundance and chemical yield requires specific calculations and treatments of the spectra as well as a manipulation of the channel contents: In a combination of emissions, energy regions are summed and evaluated with a combined efficiency that is weighted by the abundances. In a combination of spectra, the channel contents must be scaled by the ratio of the calibration factors before the summation of the spectra. In the routine monitoring of short-lived radionuclides that feature a variety of emissions such as 225Ac, these combinations are particularly effective in reducing the detectable annual effective dose. For alpha spectrometry of 225Ac, both methods applied together can lead to a detectable effective dose of about 1 mSv per year as compared to a dose of about 90 mSv with a conventional separate evaluation.

Assessment and mitigation of radiation hazard for individuals engaged in reconnaissance survey in uranium exploration in Jharkhand, India.

The present study attempts to obtain an a priori estimate of the absorbed dose received by an individual engaged in the reconnaissance survey in Uranium exploration using a predictive mathematical regression analysis. Other radiation safety parameters such as excess lifetime cancer risk are also calculated. Study reflects that the proper handling of naturally occurring radioactive materials accounts for an absorbed dose significantly less than the prescribed limit.

Studies on uranium concentration in groundwater samples and its associated health hazards to the residents of surrounding regions of Manchanabele reservoir, Bengaluru, Karnataka, India.

Uranium occurs naturally in groundwater and surface water. Being a radioactive element, high uranium concentration can cause impact on human health. The health effects associated with consumption of uranium through water includes increased cancer risk and kidney toxicity. In view of this, an attempt was made in the present study to establish the level of radiological and chemical toxicity of uranium. Radiological toxicity was evaluated in terms of lifetime cancer risk and chemical toxicity through hazard quotient. For the said purpose, groundwater samples from the selected villages of the surrounding region of the Manchanabele reservoir, southwest of Bengaluru, were collected. The collected groundwater samples were analysed for Uranium mass concentration using Light emitting diode (LED) fluorimeter and is found to range from 0.88 to 581.47 ppb with a GM of 20.82 ppb. The result reveals that ~ 66% of the samples show concentration of uranium within the safe limit of 30 ppb as set by the World Health Organisation. The radiological risk estimated in terms of lifetime cancer risk is in the range of 0.0028 × 10-3 to 1.85 × 10-3 with a GM of 0.066 × 10-3. The chemical toxicity risk measured as lifetime annual daily dose is found to range from 0.03 to 21.65 µg per kg per d with a GM of 0.77 µg per kg per d.

Organ dose equivalents of albedo protons and neutrons under exposure to large solar particle events during lunar human landing missions.

Astronauts participating in lunar landing missions will encounter exposure to albedo particles emitted from the lunar surface as well as primary high-energy particles in the spectra of galactic cosmic rays (GCRs) and solar particle events (SPEs). While existing studies have examined particle energy spectra and absorbed doses in limited radiation exposure scenarios on and near the Moon, comprehensive research encompassing various shielding amounts and large SPEs on the lunar surface remains lacking. Additionally, detailed organ dose equivalents of albedo particles in a human model on the lunar surface have yet to be investigated. This work assesses the organ dose equivalents of albedo neutrons and albedo protons during historically large SPEs in August 1972 and September 1989 utilizing realistic computational anthropomorphic human phantom for the first time. Dosimetric quantities within human organs have been evaluated based on the PHITS Monte Carlo simulation results and quality factors of the state-of-the-art NASA Space Cancer Risk (NSCR) model, as well as ICRP publications. The results with the NSCR model indicate that the albedo contribution to organ dose equivalent is less than 3 % for 1 g/cm2 aluminum shielding, while it increases to more than 30 % in some organs for 50 g/cm2 aluminum shielding during exposure to low-energy-proton-rich SPEs.

Deep-learning denoising minimizes radiation exposure in neck CT beyond the limits of conventional reconstruction.

BACKGROUND: Neck computed tomography (NCT) is essential for diagnosing suspected neck tumors and abscesses, but radiation exposure can be an issue. In conventional reconstruction techniques, limiting radiation dose comes at the cost of diminished diagnostic accuracy. Therefore, this study aimed to evaluate the effects of an AI-based denoising post-processing software solution in low-dose neck computer tomography. MATERIALS AND METHODS: From 01 September 2023 to 01 December 2023, we retrospectively included patients with clinically suspected neck tumors from the same single-source scanner. The scans were reconstructed using Advanced Modeled Iterative Reconstruction (Original) at 100% and simulated 50% and 25% radiation doses. Each dataset was post-processed using a novel denoising software solution (Denoising). Three radiologists with varying experience levels subjectively rated image quality, diagnostic confidence, sharpness, and contrast for all pairwise combinations of radiation dose and reconstruction mode in a randomized, blinded forced-choice setup. Objective image quality was assessed using ROI measurements of mean CT numbers, noise, and a contrast-to-noise ratio (CNR). An adequately corrected mixed-effects analysis was used to compare objective and subjective image quality. RESULTS: At each radiation dose level, pairwise comparisons showed significantly lower image noise and higher CNR for Denoising than for Original (p < 0.001). In subjective analysis, image quality, diagnostic confidence, sharpness, and contrast were significantly higher for Denoising than for Original at 100 and 50 % (p < 0.001). However, there were no significant differences in the subjective ratings between Original 100 % and Denoising 25 % (p = 0.906). CONCLUSIONS: The investigated denoising algorithm enables diagnostic-quality neck CT images with radiation doses reduced to 25% of conventional levels, significantly minimizing patient exposure.

Uranium Mine Proposed Experimental Design for Natural Background Gross Gamma Exposure Rates, Post Remediation Final Status Survey Sampling Density, and Radiological Water Quality Modeling for a Worst-case Catastrophic Failure, Coles Hill, Virginia.

ABSTRACT: Completely randomized experimental design statistical modeling techniques were employed to analyze exposure rate measurements for evaluating hypothetical natural background post uranium mill operations at Coles Hill, Virginia uranium milling processes. The proposed Coles Hill Uranium Mine is situated upstream of the Banister River. This River is nearly homogenous throughout the reach length used in analysis and feeds into the mouth of Kerr Reservoir, Lake Gaston, which serves as the main drinking water source for cities in the Hampton Roads area including Norfolk, Virginia Beach, and Chesapeake. A critical scan value (=DCGLscan) was developed to flag anomalies of surface contamination during simulated post remediation final status surveys. The natural background was critical for meeting the Multi-Agency Radiation Survey and Site Investigation Manual guidance for post remediation final status surveys. The overarching null hypothesis suggested that the selected mean natural background is equal to the survey unit's mean natural background. Using SAS Procedures Shapiro-Wilk Test, ANOVA, and CR, it was decided the exposure rate data was normal, had no extreme outliers, and no collinearity between the number of samples (=treatment) and the areas (=block). Using the q-hyper (hypergeometric) distribution, the soil sampling density was decided for a final status survey unit. The most likely worst-case catastrophic failure analysis, 500-year event, such as the1969 Hurricane Camille of 69 centimeters of rain in Nelson County, Virginia was included in the model. The model showed impact was minimal at most to the Banister River's drinking water and likely less than the Virginia's Drinking Water Standards for gross alpha, 226Ra and 228Ra, and total uranium.

Monitoring of surgical staff x-ray exposure in the operating room with DosiBadge.

Surgical procedures involving the use of x-rays in the operating room (OR) have increased in recent years, thereby increasing the exposure of OR staff to ionizing radiation. An individual dosimeter makes it possible to record the radiation exposure to which these personnel are exposed, but there is a lack of compliance in the wearing of these dosimeters for several practical reasons. This makes the dose results obtained unreliable. To try to improve the rate of dosimeter wearing in the OR, the Dosibadge project studied the association of the individual dosimeter with the hospital access badge, forming the Dosibadge. Through a study performed at the Tours University Hospital in eight different ORs for two consecutive periods of 3 months. The results show a significant increase in the systematic use of the dosimeter thanks to the Dosibadge, which improves the reliability of the doses obtained on the dosimeters and the monitoring of personnel. The increase is especially marked with clinicians. Following these results and the very positive feedback to this first single-centre study, we are then planning a second multicentre study to validate our proof of concept on different sites, with the three brands of individual dosimeters used in France i.e. dosimeters supplied by Dosilab; Landauer and IRSN.

Exposure to radon gas in groundwater in southwest Angola (Lubango-Huíla): Implications of geology and climate change.

In southern African countries most of the population uses groundwater collected in dug wells for domestic consumption instead of water from public distribution systems. To investigate the impact of natural and human factors on urban groundwater quality, 276 samples were collected in the Lubango region (Angola) in water distribution systems and dug wells ranging from a few meters to almost one hundred meters in depth. Radon concentrations (RC) were determined by liquid scintillation counting according to ISO 13164-4:2015. Geology is the main source of the variability of RC, with median values higher than 100 Bq/L in granitoid units and lower values in mafic and sedimentary units (ranging from 5 to 38 Bq/L). On average, RC was higher in dug wells compared to public water distribution systems. The annual effective dose due to ingestion of radon in water is, on average, ten times lower in the later compared to dug wells. Therefore, from a public exposure perspective, water distribution systems are preferred as means for water distribution. A severe multi-year meteorological drought over the past decade affecting 76-94 % of the population in southern Angola has been linked with climate change. Consequently, a regional lowering of the water table was observed, as well as a reduction in the productivity of shallower wells, leading to a search for water at greater depths. This work demonstrates an increase in median RC from 66 Bq/L in wells shallower than 30 m to values over 100 Bq/L with increasing depth of water extraction and for the same geological unit. The highest RC observed were also observed at the deepest wells. The dose ingested is proportional to RC, being also higher at deeper water extraction depths. The increase in public radiation exposure from radon ingestion due to water extraction at greater depths is attributed to the underlying issue of climate change. Monitoring water quality in terms of radionuclide concentration is advised to ensure the exposure to ionizing radiation remains at acceptable levels in the future.

Exploring the potential of combined B-mode features and color Doppler ultrasound in the diagnosis of ureteric stone as an alternative to ionizing radiation exposure by computed tomography.

OBJECTIVE: To assess the diagnostic efficacy of integrating B-mode and color Doppler capabilities of ultrasound (US) to establish a robust standalone diagnostic tool for the diagnosis of ureteric stones as an alternative to non-contrast-enhanced computed tomography (NCCT). METHODS: A total of 140 consecutive patients diagnosed with ureteric stones using NCCT were enrolled. On the same day, US in both B-mode and Color Doppler was performed by an experienced radiologist who was blinded to the NCCT scan results. The diagnostic rate of US for stone detection was recorded. Additionally, baseline patient and stone characteristics were analyzed for their association with the accuracy of stone detection using US. RESULTS: US exhibited a high sensitivity of 91.43%, detecting 128 out of 140 stone foci. Notably, ureteric stones in the proximal and uretero-vesical junction (UVJ) segments were readily identifiable compared to those in the pelvic region (p = 0.0003). Additionally, hydronephrosis enhanced the US's ability to detect stones (p < 0.0001). Conversely, abdominal gases and obesity adversely affected US capabilities (p < 0.0001 and p = 0.009, respectively). Stone side, size, and density showed no statistically significant impact (p > 0.05). CONCLUSIONS: US with its color Doppler capabilities could serve as a reliable and safe alternative imaging modality in the diagnostic work up of patients with ureterolithiasis. Factors including stone location, Hydronephrosis, weight and abdominal gases significantly influenced its accuracy.

Ensuring radiation safety: Evaluating dose and compliance among medical staff at King Faisal Medical Complex, Saudi Arabia.

BACKGROUND: Radiation is an integral part of routine medical practice, but it carries a risk to the health of medical staff. Hence, it should be assessed periodically. The study's goal was to quantify the levels of radiation exposure for medical staff at King Faisal Medical Complex (KFMC), Taif City Saudi Arabia, and to assess their radiation protective procedures in practice. METHODS: The study looked at the thermoluminescence dosimeters (TLDs) records of 50 medical professionals who were exposed to radiation while working at KFMC from 2019 to 2020 in Taif city, Saudi Arabia. In Riyadh, radiation exposure is read from skin TLDs using Harshaw model 6600 plus detectors. The Excel software was utilized to process the obtained data for calculating effective doses. A questionnaire was also distributed to the medical staff to assess their radiation protection procedures. The Statistical Package for Social Sciences (SPSS) program version 23 was used to analyze the obtained data. RESULTS: The mean annual effective doses of the medical staff in 2019 and 2020 were determined to be 1.14 mSv and 1.4645 mSv, respectively, with no significant difference in effective doses between males and females in either year. The socio-demographic features of the medical personnel were examined, and the findings revealed that the majority of participants were male radiological technologists. The rate of adherence to radiation protection techniques was 68%, with a normally distributed dispersal. The amount of adherence varied significantly depending on nationality, occupation, and academic qualification. CONCLUSION: According to the research, the mean annual effective dosage for medical professionals at KFMC was significantly below the recommended level, indicating satisfactory compliance with the ALARA radiation safety concept.

Significance of the sample determination in assessment of radiological examinations frequencies for population doses due to medical exposures.

The radiological examination frequency, i.e. the number of examinations performed annually, is necessary for estimating the collective effective dose of the population from medical exposures with ionizing radiation. Examination frequency surveys usually collect data from a limited number of radiological facilities participating in the survey. The collected data are then extrapolated to the existing radiological facilities in a country/region. Thus, the number of facilities and the specific facilities to participate, as well as, the extrapolation method used, are significant elements when designing the survey sample and methodology for examinations frequency assessments. This work attempted to simulate the situation when examination frequency data are collected from a limited number of facilities by investigating several "virtual sample" designs and two extrapolation methods. Comparisons between the calculated - by extrapolation - and the actual examination frequency in the country were made, for several scenarios and examination type data sets. The uncertainties were estimated and discussed thoroughly. The findings of this work highlighted the need for appropriate registry of the existing facilities in a country/region, the categorization of facilities considering the medical sector pattern in the country/region, the representativity and homogeneity of the samples used for a survey, as well as, the necessity for quality control of the collected examination frequency data. The results showed that when the aforementioned conditions were fulfilled, the examination frequency could be calculated with reasonable accuracy, based on data collected from a limited number of facilities. The paper also provides suggestions and tips for the collection and analysis of examination frequency data.

Has Health Physics Contributed to an 80-y False Narrative about the Trinity Nuclear Test?

ABSTRACT: This paper discusses the various analyses of the Trinity Nuclear Test, including how they might apply to the issue of infant mortality. This paper was first drafted as a response to a letter by Rice, who commented on my earlier letter on that issue. My earlier letter commented on the National Cancer Institute's 2020 series of papers in the October Issue of Health Physics on the impact of the Trinity Nuclear Test that was conducted on unoccupied government lands on 16 July 1945. The Journal editors requested that my response to Rice be edited and submitted as a paper to ensure adequate technical review and suggested that the article also add material summarizing the series of exchanges that were published in the Journal. This article suggests that significant differences exist between various summaries of the offsite impact of the Trinity Nuclear Test and offers that Trinity might be the largest nuclear accident in terms of the impact on uninvolved civilians who were downwind following the test. It suggests areas for further study to resolve these significant differences. It also asserts that until the estimated exposures of downwind residents are resolved and an appropriate study is made of infant deaths following the Trinity Nuclear Test, the issue of infant mortality remains an unanswered, 80-y-old question.

Assessment of Occupational Radiation Exposures at Ghana Research Reactor-1 Facility.

The annual occupational doses for workers at the Ghana Research Reactor-1 facility were assessed for the period 2018-2021. The dose records of monitored staff were retrieved and analysis done for dose distribution and collective effective doses. Thermoluminiscent dosimeters were used to monitor the occupational exposures. The dosimeters were evaluated for the cumulative radiation dose levels using the Harshaw 6600 TLD reader system. Annual dose of 1.52 mSv/year was the maximum acquired by an individual. An annual average effective dose range of 0.20-1.36 mSv was determined for all workers. The annual total collective effective dose was established to be in the range of 0.40-10.08 man-Sv. The 20 mSv annual limit for occupational exposure was not exceeded for monitored workers. The assessment shows that the GHARR-1 facility, in terms of radiation health effects, is a favorable environment for workers since exposures are mostly below occupational exposure limit.

Development of a body movement detection system to avoid re-exposure during radiography.

During the radiographic examination of the chest and bones in hospitals, communicating and maintaining posture is difficult for some patients, and movement before or during X-ray irradiation may necessitate re-exposure owing to body wobbling movements or breathing movements. To prevent the need for re-exposure during radiography and to determine the exposure timing, a body movement detection system that considers breathing movements was developed in this study. The posture of a patient was monitored using an RGB camera. The acquired video data was analyzed to detect body movement using either an inter-frame difference method or an optical flow estimation method. The performance of the system was evaluated by detecting the body and breathing movements during positioning. Consequently, the inter-frame difference method detected 179.8-1222.2 pixels during body movements, and the optical flow estimation method confirmed that the feature points moved by 5.5-26.6 mm (4.2-20.3 pixels). When detecting breathing movements, 82-585 pixels were detected by the inter-frame difference method, and the optical flow estimation method showed that the feature points moved by 5.2 mm (2-4 pixels). Therefore, the proposed method can detect body movements during radiography to prevent re-exposure due to body wobble and breathing movements. For healthcare providers, it will lead to reduce not only concerns about patient exposure but also unnecessary radiographic workload.