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The measurements of radon concentrations in drinking water sources in and around the Main Central Thrust (MCT) region in Garhwal Himalaya, India, were carried out using the scintillation detector-based SMART RnDuo technique for radiation protection purposes. Radon values in the analyzed samples were observed between 1.1 and 183.9 Bq L−1 (AM = 19.7 Bq L−1). Radon values in 94% of the samples were found well below the World Health Organization (WHO) reference limit. The estimated radiation doses for different age groups were found higher than the WHO safe limit of 100 µSv y−1 (from all sources including radon) except for the age groups of 0–12 months infants and 1–3 years children. The results of this study may be useful for future studies on epidemiology, examining hidden faults, uranium exploration etc. [ABSTRACT FROM AUTHOR]

To evaluate if real-time dose visualisation during computed tomography (CT)-guided interventions leads to a reduction in radiation dose to participating radiologists. The individual radiation dose radiologists are exposed to during CT interventions was measured using dedicated dosimeters (RaySafe i2-system, Unfors RaySafe GmbH, Billdal, Sweden) worn over the usual radiation protective apron. Initially, only the total radiation dose was measured, without visualisation (control group). In the following study period, the radiation dose was shown to participants on a live screen in real-time (experimental group). In both groups, the dose was recorded in 1-second intervals. The results collected were evaluated by comparison using descriptive statistics and mixed-effect models. In particular, the variables experience, gender, role, and position during the intervention were analysed. In total, 517 measurements of 304 interventions (n= 249 with and n= 268 without live screen) performed by 29 radiologists acting as interventionalists or assistants were analysed. All CT-guided interventions were performed percutaneously, the majority of which (n= 280) were microwave ablations (MWA). Radiation doses in the group without visualisation were comparable with usual dose rates for the corresponding intervention type. The mean total radiation dose was reduced by 58.1% (11.6 versus 4.86 μSv) in the experimental group (p= 0.034). The highest reduction of 78.5% (15.55 versus 3.35 μSv) was observed in radiologists with the role of assistant (p= 0.002). Sub-analysis showed significant dose reduction (p< 0.0001) for the use of live screen in general; considering all variables, the role "assistant" alone had a statistically significant influence (p= 0.002). The real-time visualisation of active radiation dose during CT interventions leads to a relevant reduction in radiation dose to participating radiologists. • Real-time dose visualisation leads to dose reduction on participating radiologists. • Most significant dose reduction was seen in radiologists in the role of "assistant". • Interventionalist's experience influences active radiation dose during interventions. [ABSTRACT FROM AUTHOR]

Simple Summary: External dose rate measurements for I-125 permanent radioactive source implantation brachytherapy for prostate cancer requires standardized external dose rate measurements and radiation safety procedures. We developed predictive models for external dose rates to ensure compliance with radiation safety guidelines. We used Monte Carlo simulation and experimental measurements to construct an external dose rate model. The model's accuracy was validated against external dose rate measurements from clinical patients. This model facilitates the calculation and minimization of family members' radiation dose, aiding in the development of personalized radiation protection strategies. This study uses Monte Carlo simulation and experimental measurements to develop a predictive model for estimating the external dose rate associated with permanent radioactive source implantation in prostate cancer patients. The objective is to estimate the accuracy of the patient's external dose rate measurement. First, I-125 radioactive sources were implanted into Mylar window water phantoms to simulate the permanent implantation of these sources in patients. Water phantom experimental measurement was combined with Monte Carlo simulation to develop predictive equations, whose performance was verified against external clinical data. The model's accuracy in predicting the external dose rate in patients with permanently implanted I-125 radioactive sources was high (R2 = 0.999). A comparative analysis of the experimental measurements and the Monte Carlo simulations revealed that the maximum discrepancy between the measured and calculated values for the water phantom was less than 5.00%. The model is practical for radiation safety assessments, enabling the evaluation of radiation exposure risks to individuals around patients with permanently implanted I-125 radioactive sources. [ABSTRACT FROM AUTHOR]

Background: Development of resistance upon exposure to small doses of ionizing radiation followed by higher doses is known as radiation-induced adaptive response (RIAR). Traditionally, the induction of the RIAR phenomenon at the cellular level has been examined in cell lines, animal models, and epidemiological studies where people live in high natural background radiation. Summary: The primary intention of the earlier studies was to corroborate the existence of RIAR and the mechanism involved in mediating the response surveyed by exposure to a low dose of radiation (<500 mGy) as priming dose toward the radiation protection point of view. However, the investigation has shifted the focus to understand the relevance of this phenomenon at clinically relevant set-ups (high doses in the order of Gy) and can be exploited during radiotherapy as RIAR is considered a mechanism for the development of radioresistance. Although the knowledge of molecular mechanisms at the cellular level has evolved significantly in multi-fractionated radiotherapy regimes, its relevance in developing radioresistance at low doses remains elusive. The authors recapitulate the existing knowledge on RIAR at cellular levels, specifically after low-dose exposure as an adaptive dose, and discussed its potential implications in clinical radiotherapy outcomes. Key Messages: Recent studies have contributed to understand the signaling molecules, pathways, and inhibitors to mitigate RIAR-mediated radiation resistance and persistent radio-tolerance at the cellular level. Monitoring the disease progression in tumor samples or liquid biopsies before, during, and after therapy with suitable biomarkers has been proposed as a strategy to translate the phenomena into clinical scenario. [ABSTRACT FROM AUTHOR]

Purpose: Intraoperative fluoroscopy use is essential during spinal fusion procedures. The amount of radiation dose should always be minimized. This study aimed to determine the feasibility of halving the frame rate from 12.5 to 6.25 frames per second (fps) and to quantify the reduction in the risk of developing radiation-induced cancer. Methods: This pilot study included 34 consecutive patients operated for open lumbar posterolateral fusion (PLF) with or without transforaminal lumbar interbody fusion (TLIF). C-arm modes were changed from half-dose (12.5 frames per second (fps), group I) to quarter-dose (6.25 fps, group II). Age, body mass index, surgical procedure, number of treated levels, and complications were collected. Kerma area product (KAP), cumulative air kerma (CAK), and fluoroscopy time were compared. Effective dose and radiation-induced cancer risk were estimated. Results: Eighteen and 16 patients were, respectively, included in group I and II. Demographic, surgical data, and fluoroscopy time were similar in both groups. However, CAK, KAP, and effective dose were significantly lower in group II, respectively, 0.56 versus 0.41 mGy (p = 0.03), 0.09 versus 0.06 Gy cm2 (p = 0.04), and 0.03 versus 0.02 mSv (p = 0.04). Radiation-induced cancer risk decreased by 47.7% from 1.49 × 10–6 to 7.77 × 10–7 after optimization. No complications were recorded in either group. Conclusion: This study demonstrates the feasibility of setting 6.25 fps for TLIF with and without PLF. By halving the fps, radiation-induced cancer risk could be almost divided by two, without compromising surgical outcome. Finally, after optimization, the risk of developing radiation-induced cancer was less than one in a million. [ABSTRACT FROM AUTHOR]

During the decommissioning process of nuclear facilities, workers are exposed to radiation and face the risk of exceeding safe dose limits. Ensuring the safety of personnel requires not only enhancing radiation protection measures but also optimizing work paths to minimize exposure time and avoid high-radiation areas. This paper proposes a nested optimization algorithm that combines an ant colony optimization (ACO) with an improved A* algorithm for the decommissioning of a nonradiation source. The algorithm aims to minimize the total radiation dose and transforms the original path optimization problem into an equivalent traveling salesperson problem. The improved A* algorithm is employed in the inner layer to calculate the path with the lowest radiation dose for any given sales order. The ACO operates in the outer layer to determine a set of optimal working paths that traverse all target points. The provided solution example demonstrates that the proposed path optimization algorithm effectively integrates the radiation field and obstacles. It successfully identifies a sequence for dismantling with the lowest dose and corresponding optimal work path while ensuring the completion of the dismantling task. These findings are expected to offer valuable insights for optimizing personnel work paths during the subsequent decommissioning process of nuclear facilities. [ABSTRACT FROM AUTHOR]

Objective: To compare the dosimetry between convex triangular fields of view (FOV) and similar dimension cylindrical FOVs of two cone-beam computed tomography (CBCT) models. Methods: Optically stimulated luminescence dosimeters (OSLDs) were placed in fiducial anatomical locations in an anthropomorphic phantom representing an adult head male for dosimetry scans. Convex triangular FOVs (100 × 80 mm/maxilla-mandible; 100 × 50 mm mandible; 100 × 50 mm/maxilla) from Veraviewepocs 3D R100 (J. Morita, Kyoto, Japan) (R100) and Veraview® X800 (J. Morita, Kyoto, Japan) (X800) and cylindrical FOVs from R100 and X800 (80 × 80 mm/maxilla-mandible; 80 × 50 mm/mandible; 80 × 50 mm/maxilla) were obtained, resulting in 12 different scan protocols. Equivalent doses for each relevant organ/tissue and the effective dose for each protocol were calculated. Mean effective doses were compared by the two-way analysis of variance (ANOVA) with Tukey's post hoc test to evaluate the effect of the FOV and device (α = 0.05). Results: The effective doses ranged between 69 and 324 μSv for the convex triangular FOVs and 76 and 332 μSv for the cylindrical FOVs. Convex triangular FOVs from the R100 device had effective doses 2.3 to 15.3% lower than their corresponding cylindrical FOVs with similar height (p < 0.05), and that difference ranged between 8.8 and 11.8% for the X800 device (p < 0.05). Conclusion: Convex triangular fields of view delivered slightly lower effective doses than the cylindrical fields of view of similar dimensions in the R100 and X800 CBCT devices. Clinical relevance: Understanding the influence of the image geometry formation in effective dose allows optimization to reduce patient dose. [ABSTRACT FROM AUTHOR]

Background: Ionizing radiation is extensively employed in diverse diagnostic procedures, playing a pivotal role in diagnosing various diseases. The escalating use of such investigations underscores the importance of judicious and careful application to mitigate associated risks and hazards. This study aims to assess doctors' knowledge regarding radiation hazards and doses in commonly used diagnostic procedures. Methods: Between July 1 and July 31, 2019, a questionnaire comprising 20 questions was distributed among doctors across various departments in a tertiary care hospital. The questionnaire, divided into three sections, covered topics such as radiological procedures employing ionizing radiation, equivalent dose units, estimation of radiation doses for common procedures, and awareness of risks linked to radiation exposure. Results: A total of 200 questionnaires were returned, representing diverse specialties. Responses from radiology (11), surgery (53), orthopedics (2), medicine (84), eye (6), ENT (4), pediatrics (9), and gynecology/obstetrics (31) were included. The assessment of doctors' knowledge in each section revealed suboptimal scores, with average correct responses of 64.1%, 21.8%, and 64.5% for the three sections, respectively. Notably, 21.3% of doctors underestimated doses, and 28% had no idea about estimated doses. Additionally, 49% and 12% of participants incorrectly categorized Magnetic Resonance Imaging (MRI) and ultrasonography as procedures involving ionizing radiation. Conclusion: This study exposes significant knowledge gaps among doctors regarding radiation doses and hazards. The findings underscore an urgent necessity for implementing institutional educational programs on radiation protection at both undergraduate and postgraduate levels. [ABSTRACT FROM AUTHOR]

The Ionising Radiation Regulations 2017 requires prior risk assessment calculations and regular environmental monitoring of radiation doses. However, the accuracy of prior risk assessments is limited by assumptions and monitoring only provides retrospective evaluation. This is particularly challenging in nuclear medicine for areas surrounding radionuclide therapy patient bathroom wastewater pipework. Machine learning (ML) is a technique that could be applied to patient booking records to predict environmental radiation dose rates in these areas to aid prospective risk assessment calculations, which this proof-of-concept work investigates. 540 days of a dosimeters historical daily average dose rate measurements and the corresponding period of department therapy booking records were used to train six different ML models. Predicted versus measured daily average dose rates for the following 60 days were analysed to assess and compare model performance. A wide range in prediction errors was observed across models. The gradient boosting regressor produced the best accuracy (root mean squared error = 1.10 µ Sv.hr−1, mean absolute error = 0.87 µ Sv.hr−1, mean absolute percentage error = 35% and maximum error = 3.26 µ Sv.hr−1) and goodness of fit (R 2 = 0.411). Methods to improve model performance and other scenarios where this approach could prove more accurate were identified. This work demonstrates that ML can predict temporal fluctuations in environmental radiation dose rates in the areas surrounding radionuclide therapy wastewater pipework and indicates that it has the potential to play a role in improving legislative compliance, the accuracy of radiation safety and use of staff time and resources. [ABSTRACT FROM AUTHOR]

Purpose: To assess accuracy, the frequency of hemorrhagic complications and computed tomography (CT) radiation dose parameters in pediatric patients undergoing landmark-guided external ventricular drain (EVD) placement in an emergency setting. Methods: Retrospective analysis comprised 36 EVD placements with subsequent CT control scans in 29 patients (aged 0 to 17 years) in our university hospital from 2008 to 2022. The position of the EVD as well as the presence and extension of bleeding were classified according to previously established grading schemes. Dose length product (DLP), volume-weighted CT dose index (CTDIvol) and scan length were extracted from the radiation dose reports and compared to the diagnostic reference values (DRLs) issued by the German Federal Office for Radiation Protection. Results: After the initial EVD placement, optimal positioning of the catheter tip into the ipsilateral frontal horn or third ventricle (Grade I), or a functional positioning in the contralateral lateral ventricle or the non-eloquent cortex (Grade II), was achieved in 28 and 8 cases, respectively. In 32 of 36 procedures, no evidence of hemorrhage was present in the control CT scan. Grade 1 (<1 mL) and Grade 2 (≥1 to 15 mL) bleedings were detected after 3 and 1 placement(s), respectively. For control scans after EVD placements, CTDIvol (median [25%; 75% quartile]) was 39.92 [30.80; 45.55] mGy, DLP yielded 475.50 [375.00; 624.75] mGy*cm and the scan length result was 136 [120; 166] mm. Exceedances of the DRL values were observed in 14.5% for CTDIvol, 12.7% for DLP and 65.6% for the scan length. None of these values was in the range requiring a report to the national authorities. Conclusion: Landmark-based emergency EVD placement in pediatric patients yielded an optimal position in most cases already after the initial insertion. Complications in terms of secondary hemorrhages are rare. CT dose levels associated with the intervention are below the reportable threshold of the national DRLs in Germany. [ABSTRACT FROM AUTHOR]

Adjuvant radiotherapy is an integral component in the management of soft-tissue sarcomas. Brachytherapy is a very convenient and conformal way of delivering adjuvant radiotherapy in such tumours, which spares the surrounding normal tissue. Randomised studies have established the efficacy of brachytherapy in the adjuvant setting, with a 5-year local control of 80–85%. High dose rate, low dose rate and pulsed dose rate have shown equivalent local control, but high dose rate has gained popularity owing to patient convenience, radiation safety and flexibility in dose optimisation. Freehand insertion perioperative brachytherapy (intraoperative placement and postoperative treatment) is the most commonly used technique in soft-tissue sarcomas, with intraoperative radiotherapy and radioactive seed placement being the less commonly used techniques. Brachytherapy can be used as monotherapy or in combination with external beam radiotherapy, such as in cases of close/positive margins for safe dose escalation. Although the quantum of side-effects with external beam radiotherapy has considerably reduced with the evolution of technology and the introduction of intensity modulation (intensity-modulated radiotherapy), brachytherapy still scores better in terms of dose conformality, especially in recurrent tumours (previously irradiated) and when used to treat paediatric and geriatric patients. • Brachytherapy allows effective disease control and organ and function preservation for soft tissue sarcomas in adult and paediatric age groups. • Appropriate selection of patient and brachytherapy technique are critical in achieving optimal outcomes. • Brachytherapy is particularly useful in children as it allows reduction in volumes of immature normal tissue irradiated. [ABSTRACT FROM AUTHOR]

Objectives: To provide radiologists and physicists with methodological tools to improve patient management after vascular fluoroscopically guided intervention (FGI) by providing optimized thresholds (OT) values that could be used as a surrogate to the thresholds classically proposed by the National Council on Radiation Protection (NCRP) or could be useful to adapt their own substantial radiation dose levels (SRDL) values. Methods: PSD of 2000–4000 mGy after FGI were calculated for 258 patients with dedicated software. Overall, the kerma and KAP 3D-ROC curves were used to assess the sensitivity (SEN) and specificity (SPE) of NCRP thresholds and OT for each PSD. Kiviat diagram and density curves were plotted for the best SEN/SPE pair of 3D-ROC curves and compared to the NCRP thresholds. Results: OT for both kerma and KAP generating the best SEN/SPE couple for PSD of 2000–4000 mGy were obtained. The SEN/SPE couple of each OT was always better than that obtained using NCRP ones. The best OT among all those calculated providing the highest SEN/SPE values for kerma (3020.5 mGy) and KAP (741.02 Gy.cm2) were obtained when PSD was equal to 3300 mGy. Conclusions: We have calculated OT in terms of kerma and KAP based on 3D-ROC curves analysis and peak skin dose calculations that can be obtained to better predict high skin dose. The use of OT that predicted PSD greater than 3000 mGy is likely to improve patient follow-up. The methodology developed in this work could be adapted to other institutions in order to better define their own SRDL. Key Points: • Optimized dose thresholds in terms of kerma and KAP based on 3D-ROC curves analysis and peak skin dose calculations between 2000 and 4000 mGy can be obtained to better predict high skin dose. • Patients receiving a peak skin dose between 2000 and 4000 mGy have their follow-up enhanced by using the optimized thresholds instead of the NCRP thresholds. • The best-optimized thresholds, corresponding to 3020.5 mGy and 741.02 Gy.cm2 for kerma and KAP respectively can be used instead of NRCP ones to trigger patient follow-up after fluoroscopically guided vascular interventions. [ABSTRACT FROM AUTHOR]

Scatter radiation from portable and pediatric X-rays could pose a risk to radiographers, nearby patients, and caretakers. We aim to evaluate the spatial scatter radiation distribution to the radiographers, nearby patients, and caretakers during common projections in portable and pediatric X-rays. We evaluated the three-dimensional scatter dose profiles of four and three commonly used portable and pediatric X-ray projections, respectively, by anthropomorphic phantoms and scatter probes. For portable X-ray, the AP abdomen had the highest scatter radiation dose recorded. Radiographer scatter radiation doses were 177 ± 8 nGy (longest cord extension) and 14 ± 0 nGy (hiding behind the portable X-ray machine). Nearby patient scatter radiation doses were 3323 ± 28 nGy (40 cm bed distance), 1785 ± 50 nGy (80 cm bed distance), and 580 ± 42 nGy (160 cm bed distance). The AP chest and abdomen had the highest scatter radiation dose in pediatric X-rays. Caretaker scatter radiation doses were 33 ± 1 nGy (50 cm height) and 659 ± 7 nGy (140 cm height). Although the estimated lens doses were all within safe levels, the use of shielding and caution on dose estimation by inverse square law is suggested to achieve the ALARA principle and dose optimization. [ABSTRACT FROM AUTHOR]

BACKGROUND: Few contemporary studies have assessed physicians' knowledge of radiation exposure associated with common imaging studies, especially in trauma care. The purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal (MSK) imaging studies routinely utilized in the trauma setting. METHODS: An electronic survey was distributed to United States orthopaedic surgery, general surgery, and emergency medicine (EM) residency programs. Participants were asked to estimate the radiation dose for common imaging modalities of the pelvis, lumbar spine, and lower extremity, in terms of chest X-ray (CXR) equivalents. Physician estimates were compared to the true effective radiation doses. Additionally, participants were asked to report the frequency of discussing radiation risk with patients. RESULTS: A total of 218 physicians completed the survey; 102 (46.8%) were EM physicians, 88 (40.4%) were orthopaedic surgeons, and 28 (12.8%) were general surgeons. Physicians underestimated the effective radiation doses of nearly all imaging modalities, most notably for pelvic computed tomaography (CT) (median 50 CXR estimation vs. 162 CXR actual) and lumbar CT (median 50 CXR estimation vs. 638 CXR actual). There was no difference between physician specialties regarding estimation accuracy (P=0.133). Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure (P=0.007). CONCLUSION: The knowledge among orthopaedic and general surgeons and EM physicians regarding the radiation exposure associated with common MSK trauma imaging is lacking. Further investigation with larger scale studies is warranted, and additional education in this area may improve care. [ABSTRACT FROM AUTHOR]

Background: Ionizing radiation is being used more frequently in medicine, which has been linked to recognized biological effects such as cancer and mortality. Radiology services are becoming more widely available in Ethiopian health facilities but there is no compiled record of worker's radiation dose. So, assessing the magnitude and identifying the associated factors of occupational radiation exposure dose among radiology personnel help to design strategies for radiation protection. Objective: The study was designed to assess the occupational radiation exposure dose and associated factors among radiology personnel in eastern Amhara, northeast Ethiopia, 2021. Methods: Cross-sectional study was conducted from March 25 to April 30, 2021, in 57 health institutions among 198 radiology personnel. The study comprised all eligible radiology personnel. The data were collected using an electronic-based (Google form) self-administered questionnaire, and document review. The data were entered into an excel spread sheet and then, exported to Stata 14 software. Linear regression model was used to analyse the data after checking its assumptions. Variables with a p-value < 0.25 were entered into a multiple linear regression analysis, and those with a p-value < 0.05 were judged significant. VIF was used to check for multi-collinearity. Coefficient of determination was used to check the model fitness. Results: The mean (± SD) annual shallow and deep dose equivalents of radiology personnel were 1.20 (± 0.75) and 1.02 (± 0.70) mSv, respectively. Body mass index (β = 0.104, 95% CI: 0.07, 0.14), practice of timing (β = -0.43, 95% CI: -0.73, -0.13), working experience (β = -0.04, 95% CI: -0.048, -0.032), and practice of distancing (β = -0.26, 95% CI: -0.49, -0.17) were found to be statistically significant factors of annual deep dose equivalent. In addition, body mass index (β = 0.113, 95% CI: 0.08, 0.15), practice of timing (β = -0.62 95% CI: -0.93, -0.31) and, working experience (β = -0.044, 95% CI: -0.053, -0.036 had statistically significant associations with annual shallow dose equivalent. Conclusion: The annual dose equivalents were two times higher than the global average of annual per caput effective dose due to medical exposure. Body mass index, practice of timing, working experience, and practice of distancing were factors of occupational radiation exposure dose. Strategies focusing on increasing the skill, experience, and lifestyle of radiology personnel would be supreme important means to reduce occupational radiation exposure dose. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the image quality of deep learning–based reconstruction (DLR), model-based (MBIR), and hybrid iterative reconstruction (HIR) algorithms for lower-dose (LD) unenhanced head CT and compare it with those of standard-dose (STD) HIR images. Methods: This retrospective study included 114 patients who underwent unenhanced head CT using the STD (n = 57) or LD (n = 57) protocol on a 320-row CT. STD images were reconstructed with HIR; LD images were reconstructed with HIR (LD-HIR), MBIR (LD-MBIR), and DLR (LD-DLR). The image noise, gray and white matter (GM-WM) contrast, and contrast-to-noise ratio (CNR) at the basal ganglia and posterior fossa levels were quantified. The noise magnitude, noise texture, GM-WM contrast, image sharpness, streak artifact, and subjective acceptability were independently scored by three radiologists (1 = worst, 5 = best). The lesion conspicuity of LD-HIR, LD-MBIR, and LD-DLR was ranked through side-by-side assessments (1 = worst, 3 = best). Reconstruction times of three algorithms were measured. Results: The effective dose of LD was 25% lower than that of STD. Lower image noise, higher GM-WM contrast, and higher CNR were observed in LD-DLR and LD-MBIR than those in STD (all, p ≤ 0.035). Compared with STD, the noise texture, image sharpness, and subjective acceptability were inferior for LD-MBIR and superior for LD-DLR (all, p < 0.001). The lesion conspicuity of LD-DLR (2.9 ± 0.2) was higher than that of HIR (1.2 ± 0.3) and MBIR (1.8 ± 0.4) (all, p < 0.001). Reconstruction times of HIR, MBIR, and DLR were 11 ± 1, 319 ± 17, and 24 ± 1 s, respectively. Conclusion: DLR can enhance the image quality of head CT while preserving low radiation dose level and short reconstruction time. Key Points: • For unenhanced head CT, DLR reduced the image noise and improved the GM-WM contrast and lesion delineation without sacrificing the natural noise texture and image sharpness relative to HIR. • The subjective and objective image quality of DLR was better than that of HIR even at 25% reduced dose without considerably increasing the image reconstruction times (24 s vs. 11 s). • Despite the strong noise reduction and improved GM-WM contrast performance, MBIR degraded the noise texture, sharpness, and subjective acceptance with prolonged reconstruction times relative to HIR, potentially hampering its feasibility. [ABSTRACT FROM AUTHOR]

Although the Diagnostic Reference Levels (DRLs) have been shown to be an important tool for optimising patient radiation protection, there are still difficulties related to the methodology that should be used to establish and use local DRL values. This statement represents the current view of the EuroSafe Imaging 'Clinical DRLs' working group formed with the purpose to produce scientific and educational material on DRLs and promote the concept of local DRLs. Guidelines on how to establish and how to use local DRLs presented herein can be implemented using a multidisciplinary team approach. Local DRLs are easy to determine and implement and they reflect local equipment performance and local clinical needs. They can be updated more frequently than the national DRLs, especially if a dose management system is available. To establish local DRLs, a practical approach could be to collect a reasonable set, i.e., at least 20–30 procedures, of data for well-defined clinical indications and calculate the 3rd quartile values. The median values of the distribution can be set to define the 'typical values'. The International Commission of Radiological Protection (ICRP) suggests setting 'typical values' for newer technologies that enable decreased amounts of radiation exposure for a similar level of image quality. Local DRLs should be similar or lower to the national DRLs. They could be higher only if the clinical benefits for some medical indications are fully explained and reported. Local DRLs may be used as a quality benchmark to track outliers and can be also used as alert values. Key points: Guidelines on how to establish and use local DRLs are presented. Local DRLs are easy to determine and implement and can be updated frequently Additionally, local DRLs can be used to track outliers. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether route of access, transradial or transfemoral, leads to any discernible differences in patient radiation or contrast medium exposure as well as procedure time in elective prostate artery embolization (PAE). Methods: This retrospective study included sixty patients in total: n = 30 in the radial PAE group, and n = 30 in the femoral PAE group. All procedures were performed in a single angiography suite between May 2018 and January 2021, using a standard kit for each type of vascular access, the same microcatheter/wire combination and embolic agent to super-selectively target and embolize one or both prostate arteries. Outcome measures included dose area product (DAP, µGym 2), air kerma (mGy), fluoroscopy time (mins), procedure time (mins) and volume of contrast medium used (mL). Adverse events were also recorded. Results: The radial and femoral groups were matched for age (73.2 ± 7.5 vs 71.3 ± 10.14, P =.41) and body mass index (27.53 ± 5.08 vs 26.41 ± 3.93, P =.38). No significant difference in dose area product, air kerma, fluoroscopy time, procedure time or volume of contrast medium used was found between radial and femoral PAE. No adverse events occurred in either group. Conclusion: Radial PAE is safe and comparable to femoral PAE with respect to patient radiation exposure, contrast medium usage, and procedure duration. Radial access is a useful skill to add to the armament of the interventional radiologist in elective PAE. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Radiation safety training remains variable among gastroenterologists performing endoscopic retrograde cholangiopancreatography (ERCP). This study sought to ascribe dosimeter readings to various real-world ERCP scenarios to provide data supporting the 3 pillars of radiation safety: distance, time, and shielding. METHODS: An ERCP fluoroscopy unit was used to generate radiation scatter from 2 differently sized anthropomorphic phantoms. Radiation scatter was measured at various distances from the emitter, with and without a lead apron, and at various frame rates (measured in frames per second, fps) and degrees of fluoroscopy pedal actuation. An image quality phantom was used to assess resolution at various frame rates and air gaps. RESULTS: Increasing the distance resulted in a decrease in measured scatter (from 0.75 mR/h at 1.5 ft to 0.15 mR/h at 9 ft with the average phantom and from 50 mR/h at 1.5 ft to 3.06 mR/h at 9 ft with the large phantom). Depressing the fluoroscopy pedal less frequently, or decreasing the frame rate (ie, increasing the time per frame), resulted in a linear decrease in scatter (from 55 mR/h at 8 fps to 24.5 mR/h at 4 fps and 13.60 mR/h at 2 fps). Providing shielding through the presence of a 0.5-mm lead apron reduced scatter (from 4.10 to 0.11 mR/h with the average phantom; from 15.30 mR/h to 0.43 mR/h with the large phantom). However, decreasing the frame rate from 8 fps to 2 fps did not change the number of line pairs identified on the image phantom. A greater air gap increased the number of line pairs resolved. CONCLUSIONS: Implementing the 3 pillars of radiation safety led to a quantifiable, clinically significant decrease in radiation scatter. The authors hope that these findings spark greater implementation of radiation safety measures among practitioners utilizing fluoroscopy. [ABSTRACT FROM AUTHOR]

Early implant migration is an indicator of the long-term survival/failure of implants. CT-based radio-stereometric analysis (CT-RSA) is a precise method for measuring and visualizing implant migration in vivo using image processing of CT scans. This makes the method widely applicable to orthopedic researcher. Since its development in the early 2000s, CT-RSA has benefited from breakthroughs in CT and computing technology. These advancements have allowed for the acquisition of images with higher resolution at a much lower radiation dose. As a result, the measurement precision of CT-RSA is now comparable to that of the current gold standard technology while still compatible with most ethical considerations regarding radiation exposure. In this review we present bests practices for the successful execution of CT-RSA research projects. These practices are based on experience from projects on the hip, knee, shoulder, lower back, cervical spine, foot, pelvis, and wrist. [ABSTRACT FROM AUTHOR]

The purpose of this study is to show the actual recommendations for dose management and provide an overview of the available options for dose tracking and dose optimization. The legal institutions that supervise the radiological exposure of patients and their most important directives are presented. A literature review of existing diagnostic reference levels for computed tomography (CT), interventional radiology, radiography, paediatric radiography, mammography, and fluoroscopy in Europe and Poland was carried out. It has been shown that, in Poland, it is necessary to verify and determine the new diagnostic reference levels (DRLs) for each imaging modality because the existing ones are adapted from other countries and are not determined on the basis of data from Polish hospitals. They have not been updated for 11-17 years, although it is recommended to update them every 3-5 years. Many countries in Europe have already determined DRLs based on the analysis of their own dosage data (e.g. Austria and Germany). Analysing the existing DRLs for CT in Poland, it was noticed that they concern only a single anatomical region. It is necessary to determine the DRLs for multi-region CT (i.e. chest-abdomen-pelvis and neck-chest-abdomen-pelvis) examinations because these examinations account for about 60% of all oncological CT examinations-based on data collected from The Maria Sklodowska-Curie National Research Institute of Oncology in Warsaw. [ABSTRACT FROM AUTHOR]

Objective: To measure the potential radiation dose emitted by patients who have recently undergone diagnostic nuclear medicine procedures, in order to establish optimal radiation safety measures for such procedures. Materials and Methods: We evaluated the radiation doses emitted by 175 adult patients in whom technetium-99m, iodine-131, and fluorine-18 radionuclides were administered for bone, kidney, heart, brain, and whole-body scans, as measured with a radiation detector. Those values served as the basis for evaluating whole-body radiopharmaceutical clearance, as well as the risk for the exposure of others to radiation, depending on the time elapsed since administration of the radiopharmaceutical. Results: The mean time to clearance of the radiopharmaceuticals administered, expressed as the effective half-life, ranged from 1.18 ± 0.30 h to 11.41 ± 0.02 h, and the mean maximum cumulative radiation dose at 1.0 m from the patients was 149.74 ± 56.72 µSv. Even at a distance of 0.5 m, the cumulative dose was found to be only half and one tenth of the limits established for exposure of the general public and family members/caregivers (1.0 mSv and 5.0 mSv per episode, respectively). Conclusion: Cumulative radiation doses emitted by patients immediately after diagnostic nuclear medicine procedures are considerably lower than the limits established by the International Commission on Radiological Protection and the International Atomic Energy Agency, and precautionary measures to avoid radiation exposure are therefore not required after such procedures. [ABSTRACT FROM AUTHOR]

Kori 1, the first commercial reactor in Korea, was permanently shut down in 2017 and is preparing for decommissioning in the mid‐2020s. Although Kori 1 is shut down, some radiation sources remain in the system; as such, the dismantling workers are exposed to radiation until decommissioning is completed. Unexpected radiation events have been reported in some decommissioning nuclear power plants (NPPs), which resulted in additional radiation exposure to workers and significant financial losses due to delays in the decommissioning schedule. Hence, an appropriate radiation protection program must be established to minimize radiation exposure as well as the economic burden. In this study, radiation doses from precedent decommissioning NPPs worldwide are compared with those estimated from Kori 1 to determine dose reduction measures that can achieve radiation exposure as low as reasonably achievable to decommissioning workers. [ABSTRACT FROM AUTHOR]

Radiation protection is nearly as old as Wilhelm Roentgen's 8 November 1895 discovery of invisible radiation. Shortly later, the harmful x-ray effects were discovered. Radiation-exposed doctors and patients frequently experienced erythema. Although ionizing radiation can harm one's health, exploratory radiological radiology is now a widespread component of clinical practice since the benefits to patients greatly exceed the risks. The objective of radiography for safe radiation-based imaging is radiation safety. This study assesses the radiation protection awareness level among radiology practitioners and medical school students. Legislative authorities limit the application of ionizing radiation. The German Committee on Radiological Protection creates policies. It ensures radiation safety in diagnostic radiology, including placing diagnostic referral standards for imaging tests used in radiology and nuclear medicine. Informational sources include reviews of particular national and international rules and legal documents. From the standpoint of the radiological safety aspect, the apparent reason for radiological technologists and methods for minimizing exposure while providing pertinent diagnostic information is crucial. Referring doctors must follow the established medical imaging standards and consult with radiologists and nuclear medicine professionals, who are also responsible for choosing appropriate imaging modalities. In its strategic plan, the International Commission on Radiation Protection (I.C.R.P.) has prioritized identifying and promoting the research required to provide radiological protection since 2011. Before beginning treatment, it is essential to have an exact diagnosis, education, and research. The current state of technology has significantly altered medical imaging. The diagnostic radiograph has become a focal point for diagnostics and clinical applications. [ABSTRACT FROM AUTHOR]

Background: The evaluation of patient doses has gotten more attention, but it's still a concern due to computerized technologies (Digital). Compared to a traditional screen-film system, the advancement of digital technology allows for a 50% reduction in radiation exposure without sacrificing image quality. Digital system provides similar or better diagnostic performance and several additional benefits, but there is a risk of overexposure without a negative impact on image quality. Digital radiographic imaging technologies are appropriate for various clinical applications and may produce satisfactory image quality across a wide exposure limit. Over radiation might result in increased dose levels without improving image quality; as a result, experimental data analysis is a continuous process that can provide information on radiation exposure appropriateness. Digital systems, on the other hand, stand out for their adaptability: the acquisition dose may be changed without compromising image quality, as well as vice versa. The imaging settings should be fine-tuned to achieve the optimum results from a given system. Traditional methods of dose containment, including placement and collimation, apply equally well to digital and traditional processes. Dose reduction is becoming increasingly possible because of digital technology. Simultaneously, there is a danger of drastically increasing the patient's dose without realizing it because of a lack of visual control. As a result, digital radiography requires dosage indicators and dose monitoring. A step closer to contemporary radiation protection is the adoption of picture quality classes based on the dose needs of specific clinical indications; manufacturers have made numerous enhancements to digital radiography equipment due to the detector and technological advancements. Because of digital imaging techniques, x-rays can now be stored digitally and used at any time by altering contrast to the viewer's preference. This technique has ensured that no radiographs are lost and enables digital distribution throughout hospitals via web-based technologies. [ABSTRACT FROM AUTHOR]

Purpose: Precise evaluation of the relative biological effectiveness (RBE) for skin reactions is indispensable for the treatment planning of particle therapy and boron-neutron capture therapy. The evaluation is also needed for the future radiation protection system for mixed radiation fields. Such RBE is often evaluated based on in vitro cell survival data, but its validity remains incompletely understood. This study aimed to develop a model for estimating RBE for skin reactions and dermal cell survival in the same framework and quantitatively discuss a possible link between them.Methods and Materials: The microdosimetric kinetic model, which was originally developed for estimating cell surviving fractions for various radiations, was improved to be capable of estimating the mean and uncertainty of RBE for skin reactions. The parameter used in the model was independently determined from in vitro measurements of dermal cell survival and in vivo measurements of skin reactions taken from 8 and 23 articles, respectively. In the parameter determination, the characteristics of the radiation fields employed in each measurement were reproduced in detail by the Particle and Heavy Ion Transport Code System.Results: Our model quantitatively revealed that RBE for skin reactions tend to be higher than those for dermal cell survival. RBE of various monoenergetic radiations calculated from this model confirmed that the past evaluations made by the International Commission on Radiological Protection and the National Council on Radiation Protection and Measurements a few decades ago are still supported by recent experimental data.Conclusions: Our model can play important roles not only in medical physics for avoiding unnecessary skin reactions in particle therapy and boron-neutron capture therapy but also in radiation protection for future decision-making of the recommended RBE values. [ABSTRACT FROM AUTHOR]

Nuclear medicine (NM) diagnostic procedures use ionizing radiation and it is necessary to ensure that the amount of prescribed activity is as low as reasonably achievable. Optimizing these procedures, one of the greatest challenges facing Nuclear Medicine today, is based on achieving a balance between image quality and radiation dose. The objective of this article is to establish and validate a method for optimization studies of medical exposure in NM simulating different levels of activity that can be applied in patients without violating the ethical and radiological protection principles. The method is based on the recombination of data obtained in gated acquisitions to simulate activity levels. For this, measurements were made using different phantoms and a signal generator. A python code was developed that allows the different activity levels to be simulated automatically from a single gated acquisition and returns the studies in the same dicom format to be reconstructed in the registered processing program provided by the manufacturer. To validate our method, the linear dependence of the number of total counts with the simulated activity levels was demonstrated and the quality of the reconstructed images vs the simulated activity levels was qualitatively evaluated. This method constitutes a valid and applicable proposal in the majority of nuclear medicine services in the country to implement optimization procedures for SPECT studies, contributing to a reduction in population exposure to radiation, due to high-tech diagnostic tests. [ABSTRACT FROM AUTHOR]

Objectives: The study aim was to analyse the influence of the lead free cap on doses received by interventional cardiologists. The impact of lead free cap on doses to the head were evaluated in number of studies. As different methods used to assess the attenuation properties of protective cap can lead to ambiguous results, a detailed study was performed.Material and Methods: The effectiveness of a lead free cap in reducing the doses to the skin was assessed in clinic by performing measurements with thermoluminescent dosimeters attached inside and outside the cap first during individual coronary angiography (CA) or CA/percutaneous transluminal coronary angioplasty (CA/PTCA) procedures and then cumulated during few procedures of the same type. In order to investigate the effect of the cap on reducing the doses to the brain additional measurements were performed with a male Alderson Rando and polymethyl methacrylate (PMMA) phantoms representing the physician and the patient, respectively for different projections. The brain dose per procedure, annual and cumulated during entire working practice were estimated for both cases working with and without the cap.Results: The dose reduction factor (RF) for the skin (the quotient of doses outside and inside the cap) vary from 1.1 up to 4.0 in clinical conditions; on average 2.3-fold reduction is observed in the most exposed left temple. The RFs determined for the part of the head covered by the cap range from 1.4 to 1.8 while for the brain from 1.0 to 1.1 depending on the projection. The estimated annual brain dose for interventional cardiologist performing yearly 550 CA/PTCA procedures without any protective shields is 7.2 mGy and it is reduced with the lead free cap by an average factor of 1.1.Conclusions: The study results proved the considerable effectiveness of lead free cap to protect the skin but very limited to protect the brain. Int J Occup Med Environ Health. 2022;35(5):549-60. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flexible radiation protection materials with excellent comprehensive properties are greatly in demand. • Well-dispersed high-Z ions/particles in the flexible matrix are the preconditions for properties. • Natural polymers contain innate advantages to construct wearable materials against radiation. • This review covers synthetic and natural polymer-based materials for radiation protection. With the rapid development of nuclear science and technology, X-rays and γ-rays are widely used in the fields of medical, military, industry, etc. However, a prolonged accumulation of radiation dosage from high-energy ionizing radiation is hazardous to human health and the surrounding environment. Traditional bulk radiation-shielding materials are bulky, heavy, and unable to meet the requirements for protecting mobile targets. To solve this problem, numerous research efforts have been focused on blending radiation absorbents with synthetic or natural polymer substrates to design lightweight and wearable shielding materials. This review aims to present a comprehensive overview of flexible and wearable radiation protection materials. To provide a clear view for readers, we discuss to start with the radiation shielding mechanisms and materials design principles. Subsequently, the state-of-the-art works on protection materials, which include lead-containing and lead-free synthetic polymer-based materials, as well as natural polymer-based materials are summarized. Additionally, the challenges of synthetic polymer-based materials and their corresponding enhancement strategies are highlighted. Finally, the possible future research and development directions are indicated for the benefit of practitioners and researchers in the field of radiation protection. [ABSTRACT FROM AUTHOR]

Simple Summary: Adjuvant radiotherapy could damage the heart in left-sided breast cancer patients. The deep-inspiration-breath-hold technique may limit the heart exposure to radiation. As non-beneficiaries exist, there is some need to do an upfront cost-effective selection. Some easy-to-use anatomical predictors may help insiders in the treatment decision. The awareness of such findings may improve the efficiency of practitioners' workflows. Radiotherapy represents an essential part of the therapeutic algorithm for breast cancer patients after conservative surgery. The treatment of left-sided tumors has been associated with a non-negligible risk of developing late-onset cardiovascular disease. The cardiac risk perception has especially increased over the last years due to the prolongation of patients' survival owing to the advent of new drugs and an ever earlier cancer detection through screening programs. Improvements in radiation delivery techniques could reduce the treatment-related heart toxicity. The deep-inspiration-breath-hold (DIBH) irradiation is one of the most advanced treatment approaches, which requires specific technical equipment and uses inspiration to displace the heart from the tangential radiation fields. However, not all patients benefit from its use. Moreover, DIBH irradiation needs patient compliance and accurate training. Therefore, such a technique may be unjustifiably cumbersome and time-consuming as well as unnecessarily expensive from a mere healthcare cost point of view. Hence the need to early select only the true beneficiaries while tailoring more effective heart-sparing techniques for the others and streamlining the workflow, especially in high-volume radiation oncology departments. In this literature overview, we collected some possible predictors of cardiac dose sparing in DIBH irradiation for left breast treatment in an effort to provide an easy-to-consult summary of simple instruments to insiders for identifying patients actually benefitting from this technique. We critically reviewed the reliability and weaknesses of each retrieved finding, aiming to inspire new insights and discussions on this much-debated topic. [ABSTRACT FROM AUTHOR]

This paper presents the various side effects of radiation including tumor cure probability (TCP) accompanied with frequently severe but transient acute side effects in the surrounding normal (mainly epithelial) tissues and also the risk of late side effects in normal organs, confined to their partial or whole volumes. Besides the local side effects, unexpected exposure to low radiation doses results in the stochastic risk of mutagenic, teratogenic or cancerogenic side effects. In order to minimize the risk of various radiation side effects, some obligatory radiation protection constraints should be restrictively fulfilled. [ABSTRACT FROM AUTHOR]

Background: The present study aimed to evaluate the effectiveness of ultra-low-dose (ULD) chest computed tomography (CT) in comparison with the routine dose (RD) CT images in detecting lung lesions related to COVID-19. Methods: A prospective study was conducted during April-September 2020 at Shahid Faghihi Hospital affiliated with Shiraz University of Medical Sciences, Shiraz, Iran. In total, 273 volunteers with suspected COVID-19 participated in the study and successively underwent RD-CT and ULD-CT chest scans. Two expert radiologists qualitatively evaluated the images. Dose assessment was performed by determining volume CT dose index, dose length product, and size-specific dose estimate. Data analysis was performed using a ranking test and kappa coefficient (κ). P<0.05 was considered statistically significant. Results: Lung lesions could be detected with both RD-CT and ULD-CT images in patients with suspected or confirmed COVID-19 (κ=1.0, P=0.016). The estimated effective dose for the RD-CT protocol was 22-fold higher than in the ULD-CT protocol. In the case of the ULD-CT protocol, sensitivity, specificity, accuracy, and positive predictive value for the detection of consolidation were 60%, 83%, 80%, and 20%, respectively. Comparably, in the case of RD-CT, these percentages for the detection of ground- glass opacity (GGO) were 62%, 66%, 66%, and 18%, respectively. Assuming the result of real-time polymerase chain reaction as true-positive, analysis of the receiver-operating characteristic curve for GGO detected using the ULD-CT protocol showed a maximum area under the curve of 0.78. Conclusion: ULD-CT, with 94% dose reduction, can be an alternative to RD-CT to detect lung lesions for COVID-19 diagnosis and follow-up. An earlier preliminary report of a similar work with a lower sample size was submitted to the arXive as a preprint. The preprint is cited as: https://arxiv.org/abs/2005.03347 [ABSTRACT FROM AUTHOR]

Patients can require imaging for several reasons. Many are for something other than annual checkups, and this can cause undue stress or fear of radiation. For parents, caregivers, and patients alike, understanding the basics of radiation and how to stay safe and get the imaging exams needed can be daunting. The information provided here will help patients and their caregivers understand the benefits and risks of radiation, and inform them not only about how radiation works, but also where and how they may encounter radiation. [ABSTRACT FROM AUTHOR]

Purpose: To assess the diagnostic confidence of intraoral radiographic image quality while reducing the pediatric patient's radiation exposure using a longer position indicating device (PID), additional X-ray beam filtration and rectangular collimation while using modern, lower-power intraoral dental X-ray units. Methods: A randomized prospective study scored bitewing intraoral dental images based on relevant clinical features. Observer studies with pediatric dentists and dental residents were conducted to verify whether diagnostic confidence remained unchanged after dose reduction modifications. The study involved a two-phase investigation to determine: (1) the best thickness of aluminum (Al) 2024-T3 alloy filter and (2) required increased exposure time to maintain intraoral radiographic image quality. A 30 cm PID with a rectangular collimator was used to further manage patient dose. For each phase, images from 125 patients were collected from February 2017 to September 2018 and analyzed. Results: The results from the observer study using a 30 cm PID, 1.02 mm thick Al alloy filter, and a rectangular collimator resulted in a patient dose reduction between 64 percent (exposure time of 400 msec) to 77 percent (250 msec), without any statistically significant effect to the diagnostic confidence of the observers in evaluating the reduced radiation images. Conclusion: Long recognized dose reduction methods, when implemented on a modern, low-power intraoral dental X-ray unit, do not impact confidence in bitewing diagnostic images, but substantially reduce patient dose and should be adopted to increase patient safety, especially for children. [ABSTRACT FROM AUTHOR]

Radiation dose management systems (DMS) are currently used to help improve radiation protection in medical imaging and interventions. This study presents our experience using a homemade DMS called DOLQA (Dose On-Line for Quality Assurance). Our DMS is connected to 14 X-ray systems in a university hospital linked to the central data repository of a large network of 16 public hospitals in the Autonomous Community of Madrid, with 6.7 million inhabitants. The system allows us to manage individual patient dose data and groups of procedures with the same clinical indications, and compare them with diagnostic reference levels (DRLs). The system can also help to prioritise optimisation actions. This study includes results of imaging examinations from 2020, with 37,601 procedures and 286,471 radiation events included in the radiation dose structured reports (RDSR), for computed tomography (CT), interventional procedures, positron emission tomography-CT (PET-CT) and mammography. The benefits of the system include: automatic registration and management of patient doses, creation of dose reports for patients, information on recurrent examinations, high dose alerts, and help to define optimisation actions. The system requires the support of medical physicists and implication of radiologists and radiographers. DMSs must undergo periodic quality controls and audit reports must be drawn up and submitted to the hospital's quality committee. The drawbacks of DMSs include the need for continuous external support (medical physics experts, radiologists, radiographers, technical services of imaging equipment and hospital informatics services) and the need to include data on clinical indication for the imaging procedures. DMS perform automatic management of radiation doses, produces patient dose reports, and registers high dose alerts to suggest optimisation actions. Benefits and limitations are derived from the practical experience in a large university hospital. [ABSTRACT FROM AUTHOR]

Intensity-modulated radiation therapy (IMRT) represents one of the most significant technical advances in radiotherapy since the advent of the medical linear accelerator, as it enables the clinical application of highly conformal and non-convex dose distributions. However, these advances do not come without risk, as IMRT represents a new paradigm in the radiation therapy process, particularly in terms of treatment quality assurance. This work focuses on one of the quality assurance aspects of IMRT, related to quality controls of multileaf collimators. A set of tests is presented to routinely evaluate the performance of this component of the accelerator to ensure the reliability and safety of the treatments. The results obtained show that most of the parameters studied comply with internationally accepted tolerances, so it is concluded that this component is suitable for use in IMRT treatments. [ABSTRACT FROM AUTHOR]

Given the lack of an internationally accepted code of practice for patient-specific quality control (PS-QA) of intensity-modulated radiation therapy (IMRT) treatments and the need to introduce this advanced modality into the clinical practice of the Radiation Therapy Service at the cedt-CIMEQ, the methodology recommended by the American Association of Physicists in Medicine Working Group 119 (AAPM TG-119) was assimilated and implemented. The procedures used for its habilitation and the results obtained are shown. It can be seen that the results obtained with the cedt-CIMEQ system for PS-QA, applied to all TG-119 test cases, fall within the confidence limits emanating from 10 reference centers. It could be concluded that, from the point of view of the reliability of the linear accelerator, the accuracy of the planning system and the precision of the PS-QA system, the cedt-CIMEQ is suitable for the introduction of IMRT in the clinic. [ABSTRACT FROM AUTHOR]

Objectives: To assess women surgeons' awareness of radiation protection protocols, cumulative dose, safety measures, radiation exposure, and breast cancer risk in India. Methods: The data were acquired through a survey monkey questionnaire circulated to women orthopaedic surgeons across the country through the WOICE group, e-mails and phone. The questionnaire assessed the respondents' awareness of radiation protection measures and level of exposure. Medical history on breast cancer during their professional life, time of diagnosis, and radiation exposure were collected. Data were analysed and expressed as percentages. Results: Fifty-one women orthopaedic surgeons responded. These were sub-grouped into early and late-career group based on whether they had worked in orthopaedics for less than 10 years (n = 33) or 10 or more years (n = 18). The mean number of years of practice of the respondents was 8.1 years, and for the group with 10 or more years was 18.7 years. 90.2% reported compliance to the lead shield, while 9.8% (n = 5) were non-compliant because of the shield's weight. Of the included respondents, 88.8% are currently working. Among all the respondents, only 13.7% (n = 7) use a radiation dosimeter. Not surprisingly, 88.2% (n = 45) of all respondents were unaware of the total radiation exposure received. Two surgeons in the more than 10-year practice category reported a history of breast carcinoma. Conclusions: This preliminary report suggested a need for more awareness of radiation protection measures among women orthopaedic surgeons. Hence, along with the practice of wearing a lead gown, use of lightweight shield, awareness on exposure measure and use of radiation dosimeter should be encouraged. [ABSTRACT FROM AUTHOR]

As a biologist who, since the beginning of her involvement in science, has collaborated closely with physicists, I want to share my forty years of experience describing the events that introduced me to the world of charged particle radiation biology as well as that of low doses/dose rates, with related implications in medicine and radiation protection. The main features of my experience can be summarized in the development of an interdisciplinary culture and in the interest in technological advances for the study of biological responses to radiation in different scenarios, relevant for public health. Mine was a journey that began by chance, but which led me to a world that proved to be of great interest to me. With the current advances in science, the new generations of scientists have new opportunities that I wish them to face with the same interest and enthusiasm that I felt for such an interdisciplinary field as that of radiation biology. [ABSTRACT FROM AUTHOR]

Monitoring the occupational radiation exposure to the operators is important from the viewpoint of radiation protection and safety. The main purpose of this study is to measure and analyze the annual radiation occupational dose to the operators in a unit of mSv in the Catheterization Laboratory (CL) at King Abdul-Aziz University Hospital (KAUH). This study measured and determined the annual effective dose to the CL operators for Twenty-Three operators at KAUH. Based on the responsibilities and position, the monitored operators were classified into different categories: Staff/Doctors, Nurses, and Technicians. The annual occupational doses were measured using Thermoluminescence dosimetry (TLD-100 (LiF: Mg, Ti)) placed at the Thyroid protective collar from the body to measure the individual dose. The calibration procedures and measurements in this study were carried out at the King Abdul-Aziz University Training and Prevention Center of the University of Radiation. The average annual dose to the CL was found to be 0.74, 1.10, 1.13, 0.65, 0.18, and 1.0 mSv for Consultants, Technicians, Nurses, Doctors, Registrar Cardiology, and Trainees respectively. More than 91% of the operators in the CL received radiation doses of less than 2 mSv. High awareness and skills are the reasons for obtaining a very low annual occupational dose in the department of CL at KAUH. The maximum value for the effective dose delivered to the operator is 2.29 mSv, which is much lower than the international dose limit (20 mSv/y) given by the International Commission of Radiological Protection (ICRP). • The annual occupational doses were measured using Thermoluminescence dosimetry (TLD-100 (LiF: Mg, Ti)). • The average annual dose to the Cath Lab operators was found to be 0.74, 1.10, 1.13, 0.65, 0.18, and 1.0 mSv. • More than 91% of the operators in the Cath Lab received radiation doses of less than 2 mSv. • High awareness, skills, and an effective radiation protection program resulted in a very low annual occupational dose. • The measured annual occupational dose for Cath Lab working operators was found to be less than 3 mSv. [ABSTRACT FROM AUTHOR]

Cardiovascular nuclear medicine (NM) imaging examinations expose patients to extremely high absorbed doses of ionizing radiation, which necessitates extensive efforts to reduce the doses without compromising the quality of images. This study aims to assess patients' radiation doses to patients and public exposure in Cardiac rest and stress single photon emission computed tomography (SPECT) scans. The patients' exposure was calculated for 21 patients using the administered activity (AA, MBq). (GE SPECT) was the device used for all patients. AA (MBq) mean and range were 370 for Rest and 1110 for Stress. The average range of the dose rate was 1.59 (0.67–2.34) mR/h for rest and 7.29 (4.2–9.98) mR/h for stress when computed at 30 cm from the patient's chest level after injection. At 100 cm from the patient, the mean dose rate values were 0.37 (0.16–0.73) mR/h for rest and 1.39 (1.01–2.0) mR/h for stress. The overall effective dose is 12.1 mSv per rest and stress SPECT procedure. The mean effective dose for cardiac rest is comparable with previously published studies while the effective dose from cardiac stress is higher than previously published studies. The variation in the effective dose depends on several factors, including the department's clinical indication imaging protocols and radiation safety measures. • The patient's effective dose and dose were quantified during cardiac rest and stress SPECT procedures. • The mean effective dose for cardiac rest is comparable with previously published studies. • The effective dose from cardiac stress is higher than previously published studies. • The current AA activity for rest and stress is lower than the DRL and the previous studies. [ABSTRACT FROM AUTHOR]

The introduction in Cuba of imaging hybrid systems in nuclear medicine has become a challenge for medical physicist in order to guaranty the patient´s radiation safety and proper dose estimation. The aim of this study was to retrospectively evaluate the CT radiation doses for studies performed with a SPECT/CT hybrid system (SPECT/CT). A MATLAB “in house” made tool was tested and validated for this purpose. 62 patients with CT studies were manually and automatically reviewed; the tool could visualize and properly recover the patient personal information, CT protocol and dose related data from the DICOM header in the SPECT/CT study file. The CT volume dose index (CTDIvol) parameter was used for calculating the CT dose-length product (DPL) and the effective doses (E). The CT radiation dose preliminary results were on the range of those reported by others authors for the typical studies, demonstrating the efficacy of the tool developed and the CT dose assessment method. [ABSTRACT FROM AUTHOR]

The use of substances to diagnose or identify a system specific phase, that is, which function as tracers, is an effective tool in the study of multiple phenomena. There are several kinds of tracers and, within them, radioactive tracers are the most sensitive and used for the study and online diagnosis of many systems, hence their use in industrial processes has an extensive use. However, an authorization from the National Regulatory Body is necessary to use radioactive sources. The safety assessment, the radiation protection program, operational and safety procedures as well as the emergency plan were prepared and presented to the Regulatory Body to apply for authorization. The safety assessment includes the dose estimations for normal operations and potential doses in accidental situations. The safety analysis used the methodology of risk matrixes. As a result, it was obtained that the doses under normal operating conditions comply with the annual limits for occupationally exposed workers and for the public, while the risk levels are predominantly low, so it was concluded that it is possible to carry out the practice under adequate security conditions and the CPHR obtained the operating license. [ABSTRACT FROM AUTHOR]

Purpose: The exposure of both patient and operator to radiation is one of the limitations of computed tomography (CT)-guided interventions, and it should be kept as low as reasonably possible. The purpose of the study was to evaluate the efficacy of a lead screen in reducing the radiation dose to an operator in the course of CT-guided interventions. Material and methods: This prospective study analysed data collected from 72 consecutive CT-guided procedures, all of which were performed with an X-ray protective lead screen placed between the scanner and the operator. Five dosimeters were placed in the CT scanning room, and accumulated radiation doses were measured for each dosimeter. Results: The dosimeter placed on the gantry side of the lead screen revealed highest levels of radiation (11.33 ± 1.93 mSv), which were significantly higher than those at all other dosimeters. The radiation dose behind the lead screen was almost the same when measured by dosimeters on the CT scanner gantry side and 3 metres away from it. The presence of the screen caused no discomfort for operators. Conclusions: A lead screen reduces an operator’s radiation exposure significantly, while not posing any obstacles or causing any discomfort while CT-guided procedures are carried out. [ABSTRACT FROM AUTHOR]

Background: Paediatric gastrointestinal fluoroscopy examinations can impart varying amounts of radiation for the same patient size and exam type. Objective: To investigate the variability of imaging protocol, radiation dose and image quality in paediatric fluoroscopy examinations in order to provide recommendations for the harmonisation and optimisation of local practices. Materials and methods: Five paediatric radiology departments performing fluoroscopically-guided contrast enema, micturating cystourethrography and upper gastrointestinal tract examinations participated in this study. Information on imaging protocols and radiation doses was retrospectively collected for more than 2,400 examinations. Image quality was analysed on clinical and phantom images. Results: Patient doses showed great variability among centers with up to a factor of 5 for similar fluoroscopy times. The five departments had imaging protocols with major differences in fluoroscopy dose regulation curves and additional filtration. Image quality analysis on phantoms and patients images showed no major improvement in contrast, spatial resolution or noise when increasing the radiation dose. Age-based diagnostic reference levels using both dose area product and fluoroscopy time were proposed per procedure type. Conclusion: Disparities between centers and no correlation of radiation dose with image quality criteria create margins for optimisation. These results highlight the need for guidelines on fluoroscopy image quality and dose reference levels in paediatric gastrointestinal examinations to harmonise practices and optimise patient dose. [ABSTRACT FROM AUTHOR]

Purpose: X‐ray cabinets are replacing 137Cs/60Co sources in radiation biology research due to advantages in size, handling, and radiation protection. However, because of their different physical properties, X‐ray cabinets are more susceptible to experimental influences than conventional sources. The aim of this study was to examine the variations related to the experimental setups typically used to investigate biological radiation effects with X‐ray cabinets. Materials and methods: A combined approach of physical dose measurements by thermoluminescence dosimetry and detection of biological effects by quantification of γH2AX and 53BP1 foci was used to analyze field inhomogeneity and evaluate the influence of the components of the experimental setup. Results: Irradiation was performed using an X‐ray tube (195 kV, 10 mA, 0.5‐mm‐thick copper filter, dose rate of 0.59 Gy/min). Thermoluminescence dosimetry revealed inhomogeneity and a dose decrease of up to 42.3% within the beam area (diameter 31.1 cm) compared to the dose at the center. This dose decrease was consistent with the observed decline in the number of radiation‐induced foci by up to 55.9 %. Uniform dose distribution was measured after reducing the size of the radiation field (diameter 12.5 cm). However, when using 15‐ml test tubes placed at different positions within this field, the dose decreased by up to 17% in comparison to the central position. Analysis of foci number revealed significant differences between the tubes for γH2AX (1 h) and 53BP1 (4 h) at different time points after irradiation. Neither removal of some tubes nor of the caps improved the dose decrease significantly. By contrast, when using 1.5‐ml tubes, dose differences were less than 4%, and no significant differences in foci number were detected. Conclusion: X‐ray cabinets are user‐friendly irradiation units for investigating biological radiation effects. However, field inhomogeneities and experimental setup components considerably affect the delivered irradiation doses. For this reason, strict dosimetric monitoring of experimental irradiation setups is mandatory for reliable studies. [ABSTRACT FROM AUTHOR]

Objectives: To assess information reflecting radiation dose and define diagnostic reference levels (DRL) on a European basis for four interventional radiology (IR) procedures considering clinical indication, anatomical region, and procedure. Methods: A prospective European study was performed to provide data on the IR procedures percutaneous recanalization of iliac arteries, percutaneous recanalization of femoropopliteal arteries, transarterial chemoembolization of hepatocellular carcinoma, and percutaneous transhepatic biliary drainage. Hospitals were asked to complete a questionnaire giving information on procedure, equipment, and protocol. Patient size and weight, experience of the operator graded in number of procedures performed, and complexity level of each procedure were reported. Sixteen hospitals from 13 countries could be surveyed. The percentiles of the kerma-area product, fluoroscopy time, cumulative air kerma at the interventional reference point, and number of images were determined. The impact of equipment, year of installation, and complexity level of the procedure on dose were analyzed. Results: DRLs based on clinical indication were defined. Dose values varied considerably within hospitals, between them, and within each subgroup of complexity level. The use of state-of-the-art equipment reduced dose significantly by 52%. Although dose also varied within each subgroup of complexity level, for transarterial chemoembolization of hepatocellular carcinoma and percutaneous transhepatic biliary drainage, dose significantly correlated with complexity. Conclusions: This was the first study reporting exposure practice and defining DRLs based on clinical indication for four IR procedures on a European basis. These DRLs can serve as a baseline for comparison with local practice, the study as a guideline for future surveys. Key Points: • The use of state-of-the-art angiographic equipment reduces dose significantly. • A significant correlation between radiation dose and complexity level is found. • Dose values vary considerably, both within and between individual hospitals, and within each complexity level of interventional radiology procedure. [ABSTRACT FROM AUTHOR]

The European Society for Therapeutic Radiology and Oncology Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) recently released new contouring guidelines for postmastectomy radiation therapy (PMRT) after implant-based reconstruction (IBR). As compared to prior ESTRO guidelines, the new guidelines primarily redefined the chest wall (CW) target to exclude the breast prosthesis. In this study, we assessed the impact of these changes on treatment planning and dosimetric outcomes using volumetric-modulated arc therapy (VMAT) and proton pencil-beam scanning (PBS) therapy. We performed a treatment planning study of 10 women with left-sided breast cancer who underwent PMRT after IBR. All target structures were delineated first using standard (ESTRO) breast contouring guidelines and then separately using the new (ESTRO-ACROP) guidelines. Standard organs-at-risk (OARs) and cardiac substructures were contoured. Four sets of plans were generated: (1) VMAT using standard ESTRO contours, (2) VMAT using new ESTRO-ACROP contours, (3) PBS using standard contours, and (4) PBS using new contours. VMAT plans using the new ESTRO-ACROP guidelines resulted in modest sparing of the left anterior descending coronary artery (LAD) (mean dose: 6.99 Gy standard ESTRO vs. 6.08 Gy new ESTRO-ACROP, p = 0.010) and ipsilateral lung (V20: 21.66% vs 19.45%, p = 0.017), but similar exposure to the heart (mean dose: 4.6 Gy vs. 4.3 Gy, p = 0.513), with a trend toward higher contralateral lung (V5: 31.0% vs 35.3%, p = 0.331) and CW doses (V5: 31.9% vs 35.4%, p = 0.599). PBS plans using the new guidelines resulted in further sparing of the heart (mean dose: 1.05 Gy(RBE) vs. 0.54 Gy(RBE), p < 0.001), nearly all cardiac substructures (LAD mean dose: 2.01 Gy(RBE) vs. 0.66 Gy(RBE), p < 0.001), and ipsilateral lung (V20: 16.22% vs 6.02%, p < 0.001). PMRT after IBR using the new ESTRO-ACROP contouring guidelines with both VMAT and PBS therapy is associated with significant changes in exposure to several cardiopulmonary structures. [ABSTRACT FROM AUTHOR]