Evaluation of Virtual Grid processed clinical pelvic radiographs.

BACKGROUND: A physical scatter grid is not often used in pelvic bedside examinations. However, multiple studies regarding scatter correction software (SC SW) are available for mobile chest radiography but the results are unclear for pelvic radiography. PURPOSE: We evaluated SC SW of Fujifilm (Virtual Grid) on gridless pelvic radiographs obtained from a human Thiel-embalmed body to investigate the potential of Virtual Grid in pelvic bedside examinations. METHODS: Gridless, Virtual Grid, and physical grid pelvic radiographs of a female Thiel-embalmed body were collected with a broad range of tube loads. Different software (SW) grid ratios-6:1, 10:1, 13:1, 17:1, and 20:1-were applied on the gridless radiographs to investigate the image quality (IQ) improvement of 13 IQ criteria in a visual grading analysis (VGA) setup. RESULTS: Gridless radiograph scores are significantly lower (p < 0.001) than Virtual Grid and physical grid scores obtained with the same tube load. Virtual Grid radiographs score better than gridless radiographs obtained with a higher tube load which makes a dose reduction possible. The averaged ratings of the IQ criteria processed with different SW ratios increase with increasing SW grid ratios. However, no statistically significant differences were found between the SW grid ratios. The scores of the physical grid radiographs are higher than those of the Virtual Grid radiographs when they are obtained with the same tube load. CONCLUSION: We conclude that Virtual Grid with an SW ratio of 6:1 improves the IQ of gridless pelvic radiographs in such a manner that a dose reduction is possible. However, physical grid radiograph ratings are higher compared to those of Virtual Grid radiographs.

Development, Feasibility, and Knowledge Impact of a Massive Open Online Course on Radiation Safety: A Multicentre Prospective Cohort Study.

OBJECTIVE: This study reports the development of an innovative, interactive Massive Open Online Course (MOOC) teaching radiation safety principles in the vascular workplace, using stepwise e-learning with multiple choice question tests (MCQs), educational videos, and a serious game. The aim was to study the MOOC impact on radiation safety knowledge and assess its feasibility and acceptability. METHODS: An international multicentre prospective study included team members active in the hybrid operating room. The MOOC was offered voluntarily via a secure online learning platform. A standardised MCQ test (15 questions) assessed radiation safety knowledge pre- and post-course (range 0 - 100%). Acceptability and feasibility were tested via the previously validated, Evaluating e-learning system success (EESS) model, using five point Likert scales. RESULTS: In eight centres across four countries, 150 of 203 invited endovascular team members consented. Over a seven week study period, surgeons (28%, including vascular surgery trainees and consultants), nurses (27%, including scrub, circulating and anaesthetic nurses), anaesthetists (43%, including trainees and consultants), and radiographers (3%) participated. Of those, 67% completed the course. The average radiation knowledge improved by 22.8% (95% CI 19.5 - 26.0%; p < .001) after MOOC completion, from 48% to 71% (standard deviation [SD] 14 and 15% respectively), requiring a mean time investment of 169 minutes (SD 89 minutes). In centres with a radiographer, mean knowledge gain after MOOC completion was significantly smaller (14%, SD 19% vs. 24%, SD 16%, p = .036). The course was deemed feasible and acceptable according to the EESS model with a total mean score of 3.68/5. CONCLUSION: This newly developed, multimodal MOOC was deemed feasible and effective across multiple international centres. The MOOC significantly contributes to radiation safety education of the entire endovascular team, improving radiation safety knowledge. The course may optimise workplace radiation safety behaviour and therefore enhance team and patient safety.

Prediction Model for Defects in Lead and Lead-free Aprons.

ABSTRACT: Personal radiation protective equipment (PRPE) is prone to defects in the attenuating layers, resulting in inadequate protection. Hence, quality control (QC) of PRPE is needed to assess its integrity. Unfortunately, QC of PRPE is laborious and time consuming. This study aimed to predict the QC outcome of PRPE without x-ray imaging based on readily available predictors. PRPE QC data of a general hospital from 2018 to 2023 was used for both prediction models based on logistic regression and random forests (RF). The data were divided into a training set containing all data from 2018 to 2022 and a holdout set containing the data from 2023. The predictors were brand, age, size, type, visual defects, and department. The prediction performances were compared using confusion matrices and visualized with receiver operating characteristic (ROC) curves. Prediction accuracies of at least 80% were achieved. Further model tuning especially improved the RF model to a precision up to 97% with a sensitivity of 80% and specificity of 86%. All predictors, except visual defects, significantly impacted the probability of passing. The predictor brand had the largest contribution to the predictive performance. The difference in pass probability between the best-performing and the worst-performing brand was 35.1%. The results highlight the potential of predicting PRPE QC outcome without x rays. The proposed prediction approach is a significant contribution to an effective QC strategy by reducing time consuming x-ray QC tests and focusing on garments with higher probability of being defective. Further research is recommended.

Absolute ground truth-based validation of computer-aided nodule detection and volumetry in low-dose CT imaging.

PURPOSE: To validate the performance of computer-aided detection (CAD) and volumetry software using an anthropomorphic phantom with a ground truth (GT) set of 3D-printed nodules. METHODS: The Kyoto Kaguku Lungman phantom, containing 3D-printed solid nodules including six diameters (4 to 9 mm) and three morphologies (smooth, lobulated, spiculated), was scanned at varying CTDIvol levels (6.04, 1.54 and 0.20 mGy). Combinations of reconstruction algorithms (iterative and deep learning image reconstruction) and kernels (soft and hard) were applied. Detection, volumetry and density results recorded by a commercially available AI-based algorithm (AVIEW LCS + ) were compared to the absolute GT, which was determined through µCT scanning at 50 µm resolution. The associations between image acquisition parameters or nodule characteristics and accuracy of nodule detection and characterization were analyzed with chi square tests and multiple linear regression. RESULTS: High levels of detection sensitivity and precision (minimal 83 % and 91 % respectively) were observed across all acquisitions. Neither reconstruction algorithm nor radiation dose showed significant associations with detection. Nodule diameter however showed a highly significant association with detection (p < 0.0001). Volumetric measurements for nodules > 6 mm were accurate within 10 % absolute range from volumeGT, regardless of dose and reconstruction. Nodule diameter and morphology are major determinants of volumetric accuracy (p < 0.001). Density assignment was not significantly influenced by any parameters. CONCLUSIONS: Our study confirms the software's accurate performance in nodule volumetry, detection and density characterization with robustness for variations in CT imaging protocols. This study suggests the incorporation of similar phantom setups in quality assurance of CAD tools.

Integrity of personal radiation protective equipment (PRPE): a 4-year longitudinal follow-up study.

BACKGROUND: Personal radiation protective equipment (PRPE) such as lead aprons minimises radiation exposure of operators using X-ray systems. However, PRPE might be prone to cracks in the attenuating layer resulting in inadequate radiation protection. This study aims to investigate the prevalence, qualification and quantification of PRPE integrity during a longitudinal follow-up study. METHODS: All PRPE of a large, general hospital was evaluated yearly in the period 2018-2021. The equipment was inspected on a tele-operated X-ray table, and tears were qualified and quantified using an X-ray opaque ruler. Rejection criteria of Lambert & McKeon, with an extra rejection criterion of 15 mm2 for individual tears, were applied to accept or reject further use of the PRPE. RESULTS: Over the 4-year follow-up period, a total of 1011 pieces of PRPE were evaluated. In total, 47.3% of the PRPE showed tears of which 31% exceeded the mentioned rejection criteria. Remarkably, of the 287 newly registered pieces of PRPE, 6.0% showed tears in the first year of use of which 88.2% needed to be rejected. Also, 48% of the repaired PRPE was rejected again in the consecutive year. CONCLUSIONS: PRPE is prone to cracks. Up to 50% of PRPE showed tears and cracks resulting in 31% rejections. Newly purchased PRPE is not guaranteed to remain free of cracks and tears in the first year of use. Repair does not guarantee a long-term solution for prolonging the lifespan. Regular X-ray-based integrity analysis of PRPE is needed to ensure adequate radioprotection for operators using X-ray systems.