Reducing radiation exposure and costs: CT body scout views with an enhanced protocol versus conventional radiography after shunt surgery.

OBJECTIVE: Ventriculoperitoneal shunt implantation has become standard treatment for cerebrospinal fluid diversion, besides endoscopic third ventriculostomy for certain indications. Postoperative X-ray radiography series of skull, chest and abdomen combined with cranial CT are obtained routinely in many institutions to document the shunt position and valve settings in adult patients. Measures to reduce postoperative radiation exposure are needed, however, there is only limited experience with such efforts. Here, we aim to compare routine postoperative cranial CT plus conventional radiography series (retrospective arm) with cranial CT and body scout views only (prospective arm) concerning both diagnostic quality and radiation exposure. PATIENTS AND METHODS: After introduction of an enhanced CT imaging protocol, routine skull and abdomen radiography was no longer obtained after VP shunt surgery. The image studies of 25 patients with routine postoperative cranial CT and conventional radiography (retrospective arm of study) were then compared to 25 patients with postoperative cranial CT and CT body scout views (prospective arm of study). Patient demographics such as age, sex and primary diagnosis were collected. The image quality of conventional radiographic images and computed tomography scout views images were independently analyzed by one neurosurgeon and one neuroradiologist. RESULTS: There were no differences in quality assessments according to three different factors determined by two independent investigators for both groups. There was a statistically significant difference, however, between the conventional radiography series group and the CT body scout view imaging group with regard to radiation exposure. The effective dose estimation calculation yielded a difference of 0.05 mSv (two-tailed t-test, p = 0.044) in favor of CT body scout view imaging. Furthermore, the new enhanced protocol resulted in a reduction of cost and the use of human resources. CONCLUSION: CT body scout view imaging provides sufficient imaging quality to determine shunt positioning and valve settings. With regard to radiation exposure and costs, we suggest that conventional postoperative shunt series may be abandoned.

Science-informed Policy Making for Protecting People and the Environment from Radiation.

ABSTRACT: The process to arrive at the radiation protection practices of today to protect workers, patients, and the public, including sensitive populations, has been a long and deliberative one. This paper presents an overview of the US Environmental Protection Agency's (US EPA) responsibility in protecting human health and the environment from unnecessary exposure to radiation. The origins of this responsibility can be traced back to early efforts, a century ago, to protect workers from x rays and radium. The system of radiation protection we employ today is robust and informed by the latest scientific consensus. It has helped reduce or eliminate unnecessary exposures to workers, patients, and the public while enabling the safe and beneficial uses of radiation and radioactive material in diverse areas such as energy, medicine, research, and space exploration. Periodic reviews and analyses of research on health effects of radiation by scientific bodies such as the National Academy of Sciences, National Council on Radiation Protection and Measurements, United Nations Scientific Committee on the Effects of Atomic Radiation, and the International Commission on Radiological Protection continue to inform radiation protection practices while new scientific information is gathered. As a public health agency, US EPA is keenly interested in research findings that can better elucidate the effects of exposure to low doses and low dose rates of radiation as applicable to protection of diverse populations from various sources of exposure. Professional organizations such as the Health Physics Society can provide radiation protection practitioners with continuing education programs on the state of the science and describe the key underpinnings of the system of radiological protection. Such efforts will help equip and prepare radiation protection professionals to more effectively communicate radiation health information with their stakeholders.

Cosmic-ray exposure assessment using particle and heavy ion transport code system: case study Douala-Cameroon.

According to UNSCEAR, cosmic radiation contributes to ~16% (0.39 mSv/y) of the total dose received by the public at sea level. The exposure to cosmic rays at a specific location is therefore a non-negligible parameter that contributes to the assessment of the overall public exposure to radiation. In this study, simulations were conducted with the Particle and Heavy Ion Transport code System, a Monte Carlo code, to determine the fluxes and effective dose due to cosmic rays received by the population of Douala. In minimum solar activity, the total effective dose considering the contribution of neutron, muon+, muon-, electron, positron and photon, was found to be 0.31 ± 0.02 mSv/y at the ground level. For maximum solar activity, it was found to be 0.27 ± 0.02 mSv/y at ground level. During maximum solar activity, galactic cosmic rays are reduced by solar flares and winds, resulting in an increase in the solar cosmic-ray component and a decrease in the galactic cosmic-ray component on Earth. This ultimately leads to a decrease in the total cosmic radiation on Earth. These results were found to be smaller than the UNSCEAR values, thus suggesting a good estimation for the population of Douala city located near the equatorial line. In fact, the cosmic radiation is more deflected at the equator than near the pole. Muons+ were found to be the main contributors to human exposure to cosmic radiation at ground level, with ~38% of the total effective dose due to cosmic exposure. However, electrons and positrons were found to be the less contributors to cosmic radiation exposure. As regards the obtained results, the population of Douala is not significantly exposed to cosmic radiation.

Electron Paramagnetic Resonance (EPR) Biodosimetry with Human Teeth: A Crucial Technique for Acute and Chronic Exposure Assessment.

ABSTRACT: Radiation exposure is a primary concern in emergency response scenarios and long-term health assessments. Accurate quantification of radiation doses is critical for informed decision-making and patient care. This paper reviews the dose reconstruction technique using both X- and Q-bands, with tooth enamel as a reliable dosimeter. Tooth enamel, due to its exceptional resistance to alteration over time, offers a unique opportunity for assessing both acute and chronic radiation exposures. This review delves into the principles underlying enamel dosimetry, the mechanism of radiation interactions, and dose retention in tooth enamel. We explore state-of-the-art analytical methods, such as electron paramagnetic resonance (EPR) spectroscopy, that accurately estimate low and high doses in acute and chronic exposure. Furthermore, we discuss the applicability of tooth enamel dosimetry in various scenarios, ranging from historical radiological incidents to recent nuclear events or radiological incidents. The ability to reconstruct radiation doses from dental enamel provides a valuable tool for epidemiological studies, validating the assessment of health risks associated with chronic exposures and aiding in the early detection and management of acute radiation incidents. This paper underscores the significance of tooth enamel as an essential medium for radiation dose reconstruction and its broader implications for enhancing radiation protection, emergency response, and public health preparedness. Incorporating enamel EPR dosimetry into standard protocols has the potential to transform the field of radiation assessment, ensuring more accurate and timely evaluations of radiation exposure and its associated risks.

Assessment of fetal radiation exposure in pregnant women undergoing computed tomography and rotational angiography examinations for pelvic trauma.

This study aimed to assess fetal radiation exposure in pregnant women undergoing computed tomography (CT) and rotational angiography (RA) examinations for the diagnosis of pelvic trauma. In addition, this study aimed to compare the dose distributions between the two examinations. Surface and average fetal doses were estimated during CT and RA examinations using a pregnant phantom model and real-time dosemeters. The pregnant model phantom was constructed using an anthropomorphic phantom, and a custom-made abdominal phantom was used to simulate pregnancy. The total average fetal dose received by pregnant women from both CT scans (plain, arterial and equilibrium phases) and a single RA examination was ~60 mGy. Because unnecessary repetition of radiographic examinations, such as CT or conventional 2D angiography can increase the radiation risk, the irradiation range should be limited, if necessary, to reduce overall radiation exposure.

Photon-counting CT-angiography in pre-TAVR aortic annulus assessment: effects of retrospective vs. prospective ECG-synchronization on prosthesis valve selection.

To compare the diagnostic value of ultrahigh-resolution CT-angiography (UHR-CTA) compared with high-pitch spiral CTA (HPS-CTA) using a first-generation, dual-source photon-counting CT (PCD-CT) scanner for preprocedural planning of transcatheter aortic valve replacement (TAVR). Clinically referred patients with severe aortic valve stenosis underwent both, retrospective ECG-gated cardiac UHR-CTA (collimation: 120 × 0.2 mm) and prospective ECG-triggered aortoiliac HPS-CTA (collimation: 144 × 0.4 mm, full spectral capabilities) for TAVR planning from August 2022 to March 2023. Radiation dose was extracted from the CT reports, and the effective dose was calculated. Two radiologists analyzed UHR-CTA and HPS-CTA datasets, assessing the image quality of the aortic annulus, with regard to the lumen visibility and margin delineation using a 4-point visual-grading scale (ranges: 4 = "excellent" to 1 = "poor"). Aortic annulus area (AAA) measurements were taken for valve prosthesis sizing, with retrospective UHR-CTA serving as reference standard. A total of 64 patients were included (mean age, 81 years ± 7 SD; 28 women) in this retrospective study. HPS-CTA showed a lower radiation dose, 4.1 mSv vs. 12.6 mSv (p < 0.001). UHR-CTA demonstrated higher image quality to HPS-CTA (median score, 4 [IQR, 3-4] vs. 3 [IQR, 2-3]; p < 0.001). Quantitative assessments of AAA from both CTA datasets were strongly positively correlated (mean 477.4 ± 91.1 mm2 on UHR-CTA and mean 476.5 ± 90.4 mm2 on HPS-CTA, Pearson r2 = 0.857, p < 0.001) with a mean error of 22.3 ± 24.6 mm2 and resulted in identical valve prosthesis sizing in the majority of patients (91%). Patients with lower image quality on HPS-CTA (score value 1 or 2, n = 28) were more likely to receive different sizing recommendations (82%). Both UHR-CTA and HPS-CTA acquisitions using photon-counting CT technology provided reliable aortic annular assessments for TAVR planning. While UHR-CTA offers superior image quality, HPS-CTA is associated with lower radiation exposure. However, severely impaired image quality on HPS-CTA may impact on prosthesis sizing, suggesting that immediate post-scan image evaluations may require complementary UHR-CTA scanning.

Assessment of dosimetric approaches in evaluating radiation exposure for interventional cardiologists in Sri Lanka.

Interventional cardiologists face significant radiation exposure during interventional cardiology procedures. Therefore, this study focuses on assessing radiation exposure among interventional cardiologists during their procedures. Specifically, it aims to determine the effectiveness of both single and double dosimeter methods in estimating annual occupational radiation doses. This research holds pioneering significance as it represents the very first study undertaken in Sri Lanka. Thirteen interventional cardiologists performed 486 interventional cardiology procedures over three months in three different healthcare institutes. Active Hp(10) dosimeters were placed to measure radiation exposure. Effective doses were calculated using single and double dosimetric algorithms. Annual occupational doses were assessed on an operator basis. Statistical analyses were conducted to assess algorithmic differences and dose variations using the Kruskal-Wallis test and linear regression. The highest annual occupational dose for each dosimetric algorithm received as 2.00 ± 0.24 mSv, 2.29 ± 0.48 mSv, 3.35 ± 0.71 mSv, and 2.64 ± 0.42 mSv, respectively, and remained below the recommended safety limit of 20 mSv/year. The Kruskal-Wallis test revealed no significant differences in the effective doses among double dosimetric algorithms, as well as between single and double dosimetric algorithms (p > 0.05). Linear regression showed strong correlations among various algorithms, demonstrating consistency. The findings of this study hold significant effects on interventional cardiology practice in Sri Lanka, enhancing radiation safety and monitoring.

Clinical image quality assessment and mean glandular dose for full field digital mammography.

This study aims to assess the image quality (IQ) of 12 mammographic units and to identify units with potential optimisation needs. Data for 350 mammography examinations meeting inclusion criteria were collected retrospectively from April 2021 to April 2022. They were categorised based on the medical reports into 10 normal cases, 10 cases displaying calcifications and 10 cases presenting lesions. Two radiologists assessed the IQ of 1400 mammograms, evaluating system performance per Boitaet al's study and positioning performance following European guidelines. To measure agreement between the two radiologists, the Cohen's Kappa coefficient (κ) was computed, quantifying the excess of agreement beyond chance. The visual grading analysis score (VGAS) was computed to compare system and positioning performance assessments across different categories and facilities. Median average glandular dose (AGD) values for cranio caudal and medio lateral oblique views were calculated for each category and facility and compared to the national diagnostic reference levels. The health facilities were categorised by considering both IQ VGAS and AGD levels. Inter-rater agreement between radiologists ranged from poor (κ< 0.20) to moderate (0.41 <κ< 0.60), likely influenced by inherent biases and distinct IQ expectations. 50% of the facilities were classified as needing corrective actions for their system performance as they had IQ or high AGD that could increase recall rate and radiation risk and 50% of the health facilities exhibited insufficient positioning performance that could mask tumour masses and microcalcifications. The study's findings emphasise the importance of implementing quality assurance programs to ensure optimal IQ for accurate diagnoses while adhering to radiation exposure guidelines. Additionally, comprehensive training for technologists is essential to address positioning challenges. These initiatives collectively aim to enhance the overall quality of breast imaging services, contributing to improved patient care.

Assessment of internal radiation exposure caused by radon in commercially bottled spring waters consumed in Turkey.

The variation of dissolved radon levels in water supplies remains of interest since radon ingested through drinking water can give considerable radiation to the lining of the stomach. This study aims to determine the radon concentration levels in bottled spring drinking water (BSW) brands commercially sold in Turkey using a radon gas monitor and to assess the internal radiation exposure caused by the ingestion and inhalation of radon. The activity concentrations of radon analyzed in 77 BSW brands varied from 7.1±0.8 to 28.7±2.7 mBq/L with an average of 15.7±5.1 mBq/L. The total annual effective dose was estimated to assess the radiological risk for three age groups in four different scenarios based on annual drinking water intake. All estimated dose values are well below the recommended reference dose of 100 µSv for drinking water. Therefore, radon gas in the investigated BSW samples poses no significant radiological risk to the public.

Patient and physician radiation exposure during minimally invasive lumbar decompression: A prospective assessment of X-ray exposure risks.

INTRODUCTION: Minimally invasive lumbar decompression (mild®) is becoming a popular procedure for treating lumbar spinal stenosis (LSS) secondary to hypertrophic ligamentum flavum (LF). The mild® procedure is commonly performed under live fluoroscopic guidance and carries a risk of radiation exposure to the patient and healthcare. METHODS: One physician performed mild® on 41 patients at the Cleveland Clinic Department of Pain Management from October 2019 to December 2021, while wearing a radiation exposure monitor (Mirion Technologies). Mean fluoroscopy time, mean exposure per case, and mean exposure per unilateral level decompressed were the primary outcomes measured. The secondary outcome was to provide a comparison of radiation exposure during similar fluoroscopically guided procedures. RESULTS: Mean patient fluoroscopy exposure time was 2.1 min ±0.9 (range: 1.1-5.6) fluoroscopy time per unilateral level decompressed. The mean patient radiation skin exposure from mild® was 1.1 ± 0.9 mGym2, and the mean total dose was 142.3 ± 108.6 mGy per procedure. On average, the physician was exposed to an average deep tissue exposure of 4.1 ± 3.2 mRem, 2.9 ± 2.2 mRem estimated eye exposure, and 14.7 ± 11.0 mRem shallow tissue exposure per unilateral level decompressed. An individual physician would exceed the annual exposure limit of 5 Rem after approximately 610 mild® procedures per year. CONCLUSIONS: This study is an attempt to quantify the radiation exposure to the physician and patient during the mild® procedure. Compared with other fluoroscopically guided pain management procedures, patient and physician radiation exposure during mild® was low.

Assessment of Cataract Risk after Diagnostic Head CT Scan Radiation Exposure in Ontario, Canada.

Ionizing radiation is one of the known risk factors for cataract development, however, there is still debate regarding the level of risk after low dose exposures. One of the largest sources of radiation exposure to the lens of the eye is diagnostic CT scans. The aim of this study was to examine whether ionizing radiation associated with head CT scans increases cataract risk in residents of Ontario, Canada. Data were collected from January 1, 1994 to December 31, 2015 (22 years) from anonymized Ontario Health Insurance Plan (OHIP) medical records for over 16 million subjects. A lens dose was estimated for each CT scan using the National Cancer Institute dosimetry system for CT (NCICT) program combined with Canada-specific CTDIvol data. Multivariate Cox proportional hazards analysis was performed with cataract extraction surgery as the primary outcome and lens dose as the main variable of interest, with inclusion of various medical and demographic covariates. Lag periods of 3, 5 and 7 years were incorporated. When lens dose was treated as a continuous variable, hazard ratios (per 100 mGy) ranged from 0.82 (0.80-0.84) to 1.10 (1.09-1.11) depending on the lag period. As a secondary analysis, when individuals were binned based on their total cumulative dose, no significant dose response pattern was observed in the low dose region. Overall, within the bounds of this study, the data do not support an increased risk of vision impairing cataracts after diagnostic head CT scan radiation exposure.

Assessment of Radiation Exposure with Mandatory Two Fluoroscopic Views for Epidural Procedures.

BACKGROUND: Various regulations and practice patterns develop on the basis of Local Coverage Determination (LCD), which are variably perceived as guidelines and/or mandated polices/ regulations. LCDs developed in 2021 and effective since December 2021 mandated a minimum of 2 views for final needle placement with contrast injection which includes both anteroposterior (AP) and lateral or oblique view. Radiation safety has been a major concern for pain physicians and multiple tools have been developed to reduce radiation dose, along with improvement in technologies to limit radiation exposure while performing fluoroscopically guided interventional procedures, with implementation of principles of As Low As Reasonably Achievable (ALARA). The mandated 2 views of epidural injections have caused concern among some physicians, because of the potential of increased exposure to ionizing radiation, despite application of various principles to minimize radiation exposure. Others, including policymakers are of the opinion that it reduces potential abuse and improves safety. OBJECTIVE: To assess variations in the performance of epidural procedures prior to the implementation of the new LCD compared with after the implementation of the new LCD by comparing time and dosage for all types of epidural procedures. STUDY DESIGN: A retrospective, case controlled, comparative evaluation of radiation exposure during epidural procedures in interventional pain management. SETTING: An interventional pain management practice and a specialty referral center in a private practice setting in the United States. METHODS: The study was performed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria. The main outcome measure was radiation exposure time measured in seconds and dose measured in mGy-kG2 (milligray to kilogray squared per procedure). RESULTS: Changes in exposure and dose varied by procedural type and location. Exposure time in seconds increased overall by 21%, whereas radiation dose mGy-kG increased 133%. Fluoroscopy time increased most for lumbar interlaminar epidural injections of 43%, followed by 29% for cervical interlaminar epidural injections, 20% for caudal epidural injections, and 14% for lumbar transforaminal epidural injections. In contrast, highest increases were observed in the radiation dose mGy of 191% for caudal epidural injections, followed by 173% for lumbar interlaminar epidural injections, 113% for lumbar transforaminal epidural injections, and the lowest being cervical interlaminar epidural injections of 94%. This study also shows lesser increases for cervical interlaminar epidural injections because an oblique view is utilized rather than a lateral view resulting in a radiation dosage increase of 94% compared to overall increase of 133%, whereas the duration of time of 29% was higher than the overall combined duration of all procedures which only increased by 21%. LIMITATIONS: A retrospective evaluation utilizing the experience of a single physician. CONCLUSION: The results of this study showed significant increases in radiation exposure time and dosage; however, increase of dosage was overall 21% median Interquartile Range (IQR) compared to 133% of radiation dose median IQR. In addition, the results also showed variations for procedure, overall showing highest increases for lumbar interlaminar epidural injections for time (43%) and caudal epidural injections for dosage (191%).

Assessment of patient and occupational exposure and radiation risk from cath-lab procedure.

Due to the extended localized fluoroscopy, many radiographic exposures, and multiple procedures that might result in tissue reaction, patients and personnel received a significant radiation dose during interventional cardiology (IR) procedures. This study aims to calculate the radiation risk and assess patient and staff effective doses during IC procedures. Thirty-two patients underwent a Cath lab treatment in total. Ten Cath lab personnel, including six nurses, two cardiologists, and two X-ray technologists. Optical stimulating-luminescent dosimeters (OSL) (Al2O3:C) calibrated for this purpose were used to monitor both occupational and ambient doses. Using an automated OSL reader, these badges were scanned. The Air Kerma (mGy) and Kerma Area Products (KAP, mGy.cm2) have a mean and standard deviation (SD) of 371 ± 132 and 26052, respectively. The average personal dose equivalent (mSv) and its range for cardiologists, nurses and X ray technologists were 1.11 ± 0.21 (0.96-1.26), 0.84 ± 0.11 (0.68-1.16), and 0.68 ± 0.014 (0.12-0.13), respectively. The current study findings showed that the annual effective dose for cardiologists, nurses, and X-ray technologists was lesser than the yearly occupational dose limit of 20 mSv recommended by national and international guidelines. The patients' doses are comparable with some previously published studies and below the tissue reaction limits.

γ-H2AX and phospho-ATM enzyme-linked immunosorbent assays as biodosimetry methods for radiation exposure assessment: a pilot study.

In the event of a radiological incident, a fast and accurate biological dosimetry (biodosimetry) method for evaluating people who have been potentially exposed to ionising radiation is crucial. Among the many biodosimetry methods available, the immunodetection of phosphorylated H2AX (γ-H2AX) stands as a promising method to be used in the triage of patients exposed to radiation. Currently, the most common way to measure γ-H2AX levels is through fluorescence microscopy. In this pilot study, we assessed the feasibility of using an enzyme-linked immunosorbent assay (ELISA) for quantifying γ-H2AX for biodosimetry purposes. Moreover, the usefulness of measuring phosphorylated ATM (pATM) levels through ELISA for biodosimetry was also evaluated. Blood samples were obtained from three male donors (38 y) and were irradiated with 60Co (0, 1, 2 and 6 Gy). Peripheral blood mononuclear cells (PBMCs) were isolated and lysed before measuring γ-H2AX, total H2AX protein and pATM using ELISA kits. The dicentric chromosome assay (DCA) using whole blood was also performed for comparison. Data from all donors at each dose were pooled before statistical analysis. The ratio of γ-H2AX/total H2AX and pATM levels increased in a radiation-dose-dependent manner. The average γ-H2AX/total H2AX ratios were 0.816 ± 0.219, 0.830 ± 0.685, 1.276 ± 1.151 and 1.606 ± 1.098, whereas the average levels of pATM were 59.359 ± 3.740, 63.366 ± 0.840, 66.273 ± 2.603 and 69.936 ± 4.439, in PBMCs exposed to 0, 1, 2 and 6 Gy, respectively. The linear-quadratic dose-response calibration curve for DCA was Y = 0.0017 (±0.0010) + 0.0251 (±0.0142) × D + 0.0342 (±0.0039) × D2  $\boldsymbol{Y}=\mathbf{0.0017}\left(\pm \mathbf{0.0010}\right)+\mathbf{0.0208}\left(\pm \mathbf{0.0218}\right)\times \boldsymbol{D}+\mathbf{0.0350}\left(\pm \mathbf{0.0050}\right)\times{\boldsymbol{D}}^{\mathbf{2}}$. Overall, despite a large variability in the ratio of γ-H2AX/total H2AX among donors, the present study revealed the suitability of using the ratio of γ-H2AX/total H2AX and pATM for biodosimetry. Still, more research with a larger group of subjects is necessary to construct a reliable calibration curve for the ratio of γ-H2AX/total H2AX and pATM levels for biodosimetry.

Preliminary assessment of the radiological consequences of the hostile military occupation of the Chornobyl Exclusion Zone.

The full-scale invasion of Ukraine by Russian military forces on 24 February 2022 put the radiological well-being of the people in Ukraine under unprecedented threat. Apart from the risks linked to operating nuclear power plants, there was substantial evidence of looting of facilities of all kinds, including those holding radioactive materials, as well as the scope for physical disturbance of radioactively contaminated areas and waste storage facilities. The actions of Russian military personnel invading Ukraine through the territory of the Chornobyl Exclusion Zone (the ChEZ) were of serious concern. Before its shutdown a few days after the beginning of the occupation, the automated radiation monitoring system of the ChEZ recorded sharp increases in the gamma-background in several areas which indicated some non-typical processes taking place on its territory. The State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) and its technical support organisation, the Scientific and Technical Centre for Nuclear and Radiation Safety (SSTC NRS), as well as the rest of the professional nuclear community in Ukraine and worldwide, recognised the potential for movement of the radioactive contamination (reaching 101-104kBq m-2Cs-137 in the most of the territory) by the Russian military machinery and personnel to areas outside the ChEZ, creating locally contaminated spots along the routes taken by the invaders towards Kyiv. Certain apprehensions were caused by the inventory carried out after the liberation of the ChEZ which revealed the theft of calibration sources and radioactive samples from laboratories located in Chornobyl. As soon as this information became available to the public, it caused a wide response and anxiety, as a result of which SNRIU made a decision to conduct a radiation survey of the liberated territories in the Kyiv region. The survey was conducted between June and December 2022 by SSTC NRS specialists with the support of DSA. The scope of the survey was limited by available time and resources; however, the total route of the survey was about 840 km, and covered more than 50 settlements and a limited part of the ChEZ. The radiation survey combined the continuous gamma-dose rate measurements by the detectors installed in the laboratory vehicle and additional manual measurements at specified points. As a result of the radiation survey, no deterioration of the radiation situation was observed in the liberated territories. No contaminated objects, radiation sources, or other radioactive material removed from the ChEZ were found either. Measurements of the Cs-137 soil contamination in the ChEZ, although limited, corresponded to the results which had been obtained before the war. It can be concluded that in the surveyed territories, the direct impact on the public in the form of additional radioactive contamination removed from the ChEZ in February-March 2022 was negligible. The same applies to the radiation consequences of forest fires that occurred in the ChEZ during its occupation. However, due to the damage of the radiation monitoring system, explosive hazard, and destruction of transport infrastructure, the consequences of the occupation of the ChEZ by Russian troops will be long-term.

Car-borne survey and dose assessment from external radiation exposure in Bangka Island.

With a history of more than 200 years of tin mining, Bangka Island has brought along a byproduct of heavy minerals containing radionuclide elements. There are some concerns about this byproduct material contributing to natural radiation in the environment. In this study, a car-borne survey was conducted to accurately assess natural background radiation in Bangka Island. Indoor and outdoor ambient dose rates in 146 houses were also measured to assess the radiation dose from external exposure received by the public. Soil samples were collected and measured using a gamma spectroscopy system to evaluate the contributions of specific radionuclides to external terrestrial exposure. From 3790 measurement points during the car-borne survey, the highest ambient dose equivalent rate was 596 nSv h-1 measured in Muntok area, with a mean value of 101 nSv h-1 and a median value of 95 nSv h-1. The ambient dose equivalent rate distribution map showed a relatively higher value in the northern coastal area of the island, where the Pemali tin deposit is located. The annual effective dose received from external radiation in the 146 houses in Bangka Island ranged from 0.44 to 1.30 mSv year-1, with a median value of 0.66 mSv year-1. The soil contained a relatively high amount of thorium (232Th), which contributed 69% to external radiation exposure in Bangka Island.

Assessment of uncertainties in threshold doses for tissue reactions following acute external radiation exposure.

The study aimed to estimate threshold doses and their uncertainties for some human health effects after short-term high dose-rate radiation exposure by quantile technique and the effective dose threshold technique based on distribution functions. The relative uncertainty (U) of the threshold dose was estimated using the error propagation technique. The quantile technique provided statistically significant estimates of threshold doses for acute radiation syndrome onset (0.44 ± 0.12 Gy, U = 143%) and lethality (1.84 ± 0.44 Gy, U = 117%) but relative uncertainties were high. The effective threshold dose technique provided statistically significant and more precise threshold dose estimates for acute radiation syndrome onset (0.73 ± 0.02 Gy, U = 18%) and lethality (6.83 ± 0.08 Gy, U = 36%), as well as agranulocytosis (3.51 ± 0.03 Gy, U = 16%) and vomiting onset in the prodromal period (1.54 ± 0.02 Gy, U = 16%). Threshold doses estimated for the change in the peripheral blood neutrophil and leukocyte counts during the first days after short-term high dose-rate radiation exposure were not statistically significant.

Radiation exposure in cone beam CT measured using a MOSFET and RPLGD dosimeter and Monte Carlo simulation in phantom.

BACKGROUND: Due to the wide application of the cone beam computed tomography (CBCT) in clinical practice, it is important to assess radiation dose of CBCT more accurately and efficiently in different clinical applications. OBJECTIVE: This study aims to calculate effective and absorbed doses in CBCT measured in an anthropomorphic phantom using computer-based Monte Carlo (PCXMC) software, and to conduct comparative evaluations of MOSFET (metal- oxide- semiconductor field-effect transistor) and radiophotoluminescence glass dosimeters (RPLGD). METHODS: Effective and absorbed organ doses are compared with those obtained using MOSFET and RPLGD dosimetry in an anthropomorphic phantom given the same exposure settings. Effective and absorbed organ doses from CBCT during scout and main projections are calculated using PCXMC and PCXMCRotation software, respectively. RESULTS: The mean effective dose from CBCT calculated using PCXMC software is 233.8µSv, while the doses calculated using dosimetry (MOSFET and RPLGD) are 266.67µSv and 268.78µSv, respectively. The X-ray source variation is 0.79%. The prescription limits based on the Friedman test for MOSFET and RPLGD pre-points (i.e., in an analytical analysis of diagnostic names in CBCT) are not statistically significant. The calculated correlation coefficient between MOSFET- and RPLGD-derived absorbed dose values with respect to a field of view CBCT parameter of 17×13.5 mm is r = 0.8623. CONCLUSIONS: The study demonstrates that the PCXMC software may be used as an alternative to MOSFET and RPLGD dosimetry for effective and absorbed organ dose estimation in CBCT conducted with a large FOV in an anthropomorphic phantom.

Multiple trauma in pregnant women: injury assessment, fetal radiation exposure and mortality. A multicentre observational study.

BACKGROUND: Fetal radiation exposure in pregnant women with trauma is a concern. The purpose of this study was to evaluate fetal radiation exposure with regard to the type of injury assessment performed. METHODS: It is a multicentre observational study. The cohort study included all pregnant women suspected of severe traumatic injury in the participating centres of a national trauma research network. The primary outcome was the cumulative radiation dose (mGy) received by the fetus with respect to the type of injury assessment initiated by the physician in charge of the pregnant patient. Secondary outcomes were maternal and fetal morbi-mortality, the incidence of haemorrhagic shock and the physicians' imaging assessment with consideration of their medical specialty. RESULTS: Fifty-four pregnant women were admitted for potential major trauma between September 2011 and December 2019 in the 21 participating centres. The median gestational age was 22 weeks [12-30]. 78% of women (n = 42) underwent WBCT. The remaining patients underwent radiographs, ultrasound or selective CT scans based on clinical examination. The median fetal radiation doses were 38 mGy [23-63] and 0 mGy [0-1]. Maternal mortality (6%) was lower than fetal mortality (17%). Two women (out of 3 maternal deaths) and 7 fetuses (out of 9 fetal deaths) died within the first 24 h following trauma. CONCLUSIONS: Immediate WBCT for initial injury assessment in pregnant women with trauma was associated with a fetal radiation dose below the 100 mGy threshold. Among the selected population with either a stable status with a moderate and nonthreatening injury pattern or isolated penetrating trauma, a selective strategy seemed safe in experienced centres.