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Funding Information: On behalf of the Public and Community Oversight Group (PCOG) of the Health Protection Research Unit in Chemical and Radiation Threats and Hazards: Ian Wright; John Phipps; Colette Kelly; Robert Goundry; Eve Smyth; Andrew Wood; Paul Dale (also of the Scottish Environment Protection Agency). On behalf of the Society and College of Radiographers Patient Advisory Group: Lynda Johnson; Philip Plant; Michelle Carmichael – Specialist Senior Staff Nurse Guy's and St Thomas’ NHS Foundation trust.

The objective is to investigate tumour prognostic factors versus breast density in screen-detected cancers and interval cancers. The results may highlight the need for more personalised screening protocols based on breast density in organized screening programmes.A retrospective study was performed of tumour characteristics of screen-detected cancers (n=468) and interval cancers (n=515) of 983 women who participated in the Flemish Breast Cancer Screening Programme in 2009-2010. Breast density was obtained from the screening programme data. Information on nodal invasion and histological grading was taken from the Belgian Cancer Registry. Tumour size and proliferation and receptor expression status were retrieved from pathology reports. The differences in tumour characteristics between screen-detected and interval cancers as well as the variation in these variables with breast density in both groups were studied by logistic regression.A comparison of tumour characteristics between screen-detected cancers and interval cancers systematically showed features of more aggressive tumours in interval cancers: larger tumour size, nodal invasion, grade 3 tumours, and hormone receptor negative phenotype (p0.05). The analysis of tumour characteristics versus breast density in screen-detected cancers showed higher numbers of aggressive grade 3 tumours in low-density breasts and of the luminal A subtype with good prognosis in high-density breasts (p0.05). This analysis for interval cancers highlights a high proportion of the difficult-to-treat triple-negative subtype in low-density breasts compared with high-density breasts. In conclusion, the study data support arguments against changes in breast cancer screening programmes with prolongation of screening intervals in low-density breasts.

Purpose: Feasability of a no-reference image quality metric was assessed on patient-like images using a patient-specific phantom simulating a frame of a coronary angiogram. Methods: One background and one contrast-filled frame of a coronary angiogram, acquired using a clinical imaging protocol, were selected from a Philips Integris Allura FD (Philips Healthcare, Best, The Netherlands). The background frame's pixels were extruded to a thickness proportional to their grey value. One phantom was 3D printed using composite 80% bronze filament (max. thickness of 5.1 mm), the other was a custom PMMA cast (max thickness of 8.5 cm). A vessel mold was created from the contrast-filled frame and injected with a solution of 320 mg I/ml contrast fluid (75%), water and gelatin. Still X-ray frames of the vessel mold + background phantom + 16 cm PMMA were acquired at manually selected different exposure settings using a Philips Azurion (Philips Healthcare, Best, The Netherlands) in User Quality Control Mode and were exportedas RAW images. The signal-difference-to-noise-ratio-squared (SDNR2) and a spatial-domain-equivalent of the noise equivalent quanta (NEQSDE) were calculated. The Spearman's correlation of the latter parameters with a no-reference perceptual image quality metric (NIQE) was investigated. Results: The bronze phantom showed better resemblance to the original patient frame selected from a coronary angiogram of an actual patient, with better contrast and less blur than the PMMA phantom. Both phantoms were imaged using a comparable imaging protocol to the one used to acquire the original frame. The bronze phantom was hence used together with the vessel mold for image quality measurements on the 165 still phantom frames. A strong correlation was noted between NEQSDE and NIQE (SROCC = –0.99, p < 0.0005) and between SDNR2 and NIQE (SROCC = –0.97, p < 0.0005). Conclusion: Using a cost-effective and easy to realize patient-specific phantom we were able to generate patient-like X-ray frames. NIQE as a no-reference image quality model has the potential to predict physical image quality from patient images.

Purpose In laparoscopy, the Operating Room Black Box® (ORBB) provides insights into operative performance to improve patient safety. This technology may also enhance endovascular surgical practice; however, the use of a C-arm and X-rays pose important challenges, hindering transferability to an endovascular context. We describe the first implementation of ORBB technology in a hybrid angiosuite and illustrate its value in evaluating surgeons’ radiation safety, technical and non-technical performance. Methods Team members (surgeons, nurses, anaesthesiologists) and stakeholders were informed during several information sessions. Together with teams from Surgical Safety Technologies (Toronto, Canada), an implementation plan was developed, and video-evaluation frameworks were chosen. Radiation safety was assessed using dose measurements and video-evaluation of safety-related behaviours. Technical performance was assessed using ‘global’ (GRS) and ‘procedure-specific’ (PRS) rating scales and the ‘EndoVascular Aortic Repair Assessment of Technical Expertise’ (EVARATE) framework. Surgeons’ non-technical skills were assessed with the NOTSS framework. Results The system captures Audio-visual data from four ceiling-mounted cameras, three ceiling-array microphones, the fluoroscopy screen and anaesthesia monitor. After patient and team consent, an elective endovascular aneurysm repair was successfully analysed. Dose-Area-Product and Air Kerma were 71094 mGy.cm2 and 270 mGy, respectively. Behavioural analysis revealed deficiencies in stepping back and radiation safety communication. Technical skill assessment was feasible: GRS: 29/40; ‘PRS’: 27/35; EVARATE: 29/35. Non-technical analysis highlighted surgeons’ leadership qualities. Conclusion An innovative data capture platform has been successfully installed to evaluate overall performance during endovascular procedures. This technology may facilitate identification of (radiation) safety-related errors and instigate educational interventions based on real-world issues.

Mobile radiography systems are commonly used in the intensive care unit. The use of a physical antiscatter grid with these systems is uncommon because of drawbacks. In 2015, Virtual Grid (Fujifilm, Tokyo, Japan) became available for chest and abdomen examinations. In this study, we compared image quality (IQ) with a contrast-detail phantom (CDRAD 2.0; Artinis Medical Systems, Zetten, the Netherlands) of digital radiographs acquired without any grid (gridless) with those corrected for scatter by either software (SW)-based scatter correction (Virtual Grid) or a physical grid (grid). Furthermore, we determined the optimal Virtual Grid settings that lead to the best contrast-detail IQ score (inverse IQ figure). MATERIALS AND METHODS Images were obtained with a cassette spot film device with an inserted portable flat-panel detector (Fujifilm, Tokyo, Japan). The CDRAD phantom was sandwiched between polymethylmethacrylate (PMMA) with total thicknesses of 12, 16, 21, and 26 cm to simulate patient attenuation and scatter. Tube voltages of 81, 90, 109, and 125 kVp were used to make the radiographs. In total, 12 different Virtual Grid settings (grid ratio, line pairs (lp)/cm, and type of interstitial material) were applied for every phantom thickness and tube voltage. RESULTS An average increase of 32% in IQ was obtained when Virtual Grid images with a SW grid ratio 10:1 were compared with gridless images (P < 0.001). Increasing the SW grid ratio to 20:1 resulted in a further increased IQ. With a phantom thickness of 12 cm PMMA, Virtual Grid outperformed the removable physical grid presented in the cassette spot film device. The linear mixed-effects model showed that IQ is mainly affected by PMMA, tube voltage, and the SW grid ratio. CONCLUSIONS Virtual Grid improves images obtained without physical grid for a wide range of experimental conditions. Despite the different possible settings of the Virtual Grid SW, the most important parameter affecting IQ is the SW grid ratio.

Objectives Bedside radiographs are usually obtained gridless, without a physical scatter correction grid because of several limitations. Therefore, multiple manufacturers of mobile radiography systems provide the possibility to apply scatter correction software (SC SW) on those images. The purpose of this study was to characterize different series of radiographs-gridless, SC SW, and physical grid-with an image quality assessment algorithm (IQAA). Furthermore, we investigated the potential dose reduction and the correlation between the output of the IQAA and the human observers. Materials and Methods We obtained different series of radiographs with an anthropomorphic phantom (multipurpose chest phantom N1 "Lungman," Kyoto Kagaku, Kyoto, Japan). All radiographs were obtained with flat-panel detectors of 5 different manufacturers in a wall bucky system. An IQAA to analyze the radiographs was implemented in our department but was originally developed by the research group of the Duke University Medical Center. Seven physical quantities were calculated by the IQAA: rib-lung contrast (RLcontrast), subdiaphragm-lung contrast (SLcontrast), lung detail (L-detail), mediastinum detail (M-detail), lung noise (L-noise), mediastinum noise (M-noise), and rib-lung sharpness (RLsharpness). In a proof of concept, the results of the IQAA were validated by 3 experienced radiologists. Results Regression coefficients (b) of the linear regression model indicate that the human observer results correlate well with the IQAA (b >= 0.89, R-2 >= 0.83). All manufacturers have SC SW that increases the 7 physical quantities of the gridless images. However, several manufacturers have SC SW that increases the physical metrics to the same level as the physical grid images. The SC SW radiographs obtained with a reduced tube load have an increased level of contrast, detail, sharpness, and noise compared with the gridless images obtained with the higher tube load. Conclusions We have proven in a proof of concept that the originally developed IQAA can be used to characterize different series of images of different manufacturers. Based on the physical quantities, SC SW increases the contrast, detail, sharpness, and noise. The experimental results in this study assume a patient dose reduction could be possible when SC SW is applied.

To study number and type of imaging techniques, cumulative radiation exposure and radiation-induced risk from repeated imaging of cervical and lumbar spine attained after traffic or occupational accident.The study cohort comprised of 500 patients after traffic or occupational accident. Amount of radiography, CT and MRI procedures and injury severity were tallied for each patient. Cumulative effective dose (CED), expressed in millisieverts (mSv), was estimated by summing up typical effective dose values. Total lifetime cancer risks and associated risk category were estimated by using risk coefficients, specified according to sex, age at exposure and exposed region.A total of 2,107 imaging procedures were performed of which 30% were radiographs (n = 631), 21% were CT (n = 438) and 49% were MRI (n = 1,038). Abbreviated Injury Scale was low (1-2) in all cases (except one). The cohort included 352 patients after traffic accident and 148 after occupational accident. Mean CED of these two groups were 4.4 mSv and 9.4 mSv, respectively. No patient had a CED higher than 100 mSv. Nineteen patients fell into the 'moderate risk' group, meaning that the additional risk of fatal cancer from accumulated radiation exposure lies between 1 in 1,000 and 1 in 100.MRI was the most used imaging technique. No CED from repeated imaging procedures after minor or moderate traffic or occupational accident exceeded 100 mSv. However, nineteen patients fell into the 'moderate risk' group of developing radiation-induced cancer. Tracking radiation exposure can be beneficial in identifying those with high CED, although education on its proper use is necessary.

Objectives We evaluated the different Virtual Grid software ratios (Fujifilm, Tokyo, Japan) on gridless clinical chest radiographs with visual grading analysis (VGA). In addition, we investigated the 2 image quality assessment algorithms (IQAAs). Materials and Methods Gridless chest radiographs of 50 different intensive care unit patients were collected and afterward processed with Virtual Grid software. Different software (SW) grid ratios-6:1, 10:1, 13:1, 17:1, and 20:1-were applied to investigate the image quality (IQ) improvement. Image quality improvement was assessed by 4 radiologists in a relative VGA study where the reference image was processed with SW grid ratio of 10:1. One of the IQAAs used to analyze the radiographs was implemented in our department but was originally developed by the research group of the Duke University Medical Center. A general IQ score (IQS) was calculated based on contrast, detail, and noise. Another IQAA-NIQE (naturalness image quality evaluator)-available in Matlab (MATLAB Research R2019b; the MathWorks, Inc) was evaluated. Both methods were compared with VGA. Results Visual grading analysis scores of gridless radiographs are significantly lower (P < 0.001). Image quality increases with increasing SW grid ratios, up to grid ratio of 17:1. However, some anatomical structures-spine and ribs-are negatively affected by the higher grid ratios. A correlation coefficient of 0.99 between the VGA and the IQS was observed. The correlation coefficient between VGA and NIQE was 1.00. Conclusions Virtual Grid with SW grid ratio of 6:1 improves the IQ of gridless chest bedside radiographs. The grid ratios 17:1 and 20:1 should be considered carefully as the SW negatively affects parts of the ribs and spine. Therefore, grid ratios up to 13:1 can be advised. The IQAAs are promising and could be used to detect differences in IQ when different scatter correction SW settings are used.

Background Personal radiation protective equipment (PRPE) such as lead aprons, vests, skirts and thyroid shields minimize radiation exposure of operators using ionizing radiation. However, PRPE might be prone to cracks and tears in the attenuating layer of the garments which results in inadequate radiation protection and increased operator dose. Currently, there are no uniform guidelines regarding regular inspection and/or rejection criteria of PRPE. Purpose This study aims to investigate the prevalence, qualification and quantification of PRPE integrity during a longitudinal follow-up. Methods All PRPE of a large, general hospital was yearly evaluated in the period 2018–2020. The equipment was inspected on a tele-operated X-ray table and cracks and tears were qualified and quantified using an X-ray opaque ruler. Rejection criteria of Lambert & McKeon were applied to accept or reject further use of the PRPE. In brief, all pieces, except for thyroid shields, with a total defect area larger than 670mm2 are rejected. For tears, specifically at the position of the gonads, an extra rejection criterion of 15mm2 is defined. For thyroid shields, the rejection criterion is set to 11mm2. Results In the 3-year follow-up period, a total of 915 PRPE were evaluated. 43.3% of PRPE showed tears and 29.3% needed to be rejected based on the Lambert & McKeon criteria. More specifically, in 2018, 2019 and 2020, respectively, 17.4%, 16.9% and 21.2% were rejected. In the attached figure, typical examples of visualized defects are represented. The median tear area (interquartile range) was 12 (30) mm2. Remarkably, of 195 newly registered PRPE, 8.7% showed tears in the first year of use of which 88.2% needed to be rejected. In the latter case, the median tear area (interquartile range) was 40 (50) mm2. Information regarding purchase date and size is missing in respectively 45.5% and 50.7% of the cases. Additionally, 13.7% lacked information regarding lead equivalency. Conclusion PRPE are prone to tears and cracks. Up to 40% of PRPE showed tears and cracks resulting in nearly 20% rejections. Newly purchased PRPE are not guaranteed to remain free of cracks and tears in the first year of use. These results urge the importance for regular X-ray based integrity analysis of PRPE. Funding Acknowledgement Type of funding sources: None.

Micro-CT imaging is an increasingly popular tool in the internal investigation of objects and materials. However, as an X-ray based technique, a potentially harmful radiation dose is deposited in the sample during the measurement. In (non small-animal) micro-CT imaging one is dealing with a strong variation in measurement systems and settings, resulting in many different acquisition circumstances and the absence of standard imaging protocols. Therefore, the deposited dose is rarely studied for micro-CT applications. This research aimed at developing a fast simulation technique to predict the dose associated with micro-CT scanning. Its performance is compared with that of two different Monte Carlo simulation tools and with a straight forward approach to estimate an upper limit for the dose. The fast simulation method, obtaining a dose estimation based on the energy absorption coefficient, is much faster than the Monte Carlo simulations, and the results are accurate within 30%. This enables us to predict the dose for a known sample and a known scanner setup, without complex Monte Carlo simulations and will allow researchers to avoid radiation damage or unwanted radiation induced effects, an increasingly important concern in 3D and 4D micro-CT scanning.

Prostate specific membrane antigen (PSMA) is highly overexpressed in prostate cancer. Many PSMA analogue radiotracers for PET/CT imaging of prostate cancer staging have been developed such as 68Ga-PSMA-11. This radiotracer has achieved good results in multiple clinical trials, but because of superior imaging characteristics of 18F-fluoride, 18F-PSMA-11 was developed. The aim of this study was to evaluate the safety of administration and the radiation dosimetry of 18F-PSMA-11. METHODS: Six patients (age 62-68y, mean 66 ± 2y) with suspected prostate cancer recurrence after previous treatment were administered 2 MBq/kg bodyweight 18F-PSMA-11 followed by PET/CTlow-dose imaging at 0, 20, 50, 90 and 300 min post injection (p.i.). To evaluate the safety of administration, vital parameters were monitored. To assess toxicity, full blood count and biochemical parameters were determined. According to the latest ICRP recommendations, radiation dosimetry analysis was performed using IDAC-Dose 2.1. For blood activity measurement, small samples of venous blood were collected at various timepoints p.i. The unbound 18F-fluoride fraction was determined in plasma 20, 50 and 90 min after administration to evaluate the defluorination rate of 18F-PSMA-11. RESULTS: After injection, 18F-PSMA-11 was rapidly cleared from the blood. 29.0 ± 5.9% of the activity was excreted in urine at 5h p.i. The free 18F fraction in plasma increased from 9.7 ± 1.0% 20 min p.i. to 22.2 ± 1.5% 90 min p.i. The highest tracer uptake was observed in kidneys, bladder, spleen and liver. No study drug related adverse events were observed. The calculated mean effective dose was 12.8 ± 0.6 µSv/MBq. CONCLUSION:18F-PSMA-11 can be safely administered and results in a mean effective dose of 12.8 ± 0.6 µSv/MBq. Therefore, the total radiation dose is lower compared to other PSMA PET agents and in the same range of 18F-DCFPyL.

Background Dual axis rotational coronary angiography ( DARCA ) reduces radiation exposure during coronary angiography on older x‐ray systems. The purpose of the current study is to quantify patient and staff radiation exposure using DARCA on a modality already equipped with dose‐reducing technology. Additionally, we assessed applicability of 1 dose area product to effective dose conversion factor for both DARCA and conventional coronary angiography ( CCA ) procedures. Methods and Results Twenty patients were examined using DARCA and were compared with 20 age‐, sex‐, and body mass index–matched patients selected from a prior study using CCA on the same x‐ray modality. All irradiation events are simulated using PCXMC ( STUK , Finland) to determine organ and effective doses. Moreover, for DARCA each frame is simulated. Staff dose is measured using active personal dosimeters (DoseAware, Philips Healthcare, The Netherlands). With DARCA , median cumulative dose area product is reduced by 57% (ie, 7.41 versus 17.19 Gy·cm 2 ). Effective dose conversion factors of CCA and DARCA are slightly different, yet this difference is not statistically significant. The occupational dose at physician's chest, leg, and collar level are reduced by 60%, 56%, and 16%, respectively, of which the first 2 reached statistical significance. Median effective dose is reduced from 4.75 mSv in CCA to 2.22 mSv in DARCA procedures, where the latter is further reduced to 1.79 mSv when excluding ventriculography. Conclusions During invasive coronary angiography, DARCA reduces radiation exposure even further toward low‐dose values on a system already equipped with advanced image processing and noise reduction algorithms. For both DARCA and CCA procedures, using 1 effective dose conversion factor of 0.30 mSv·Gy −1 ·cm −2 is feasible.

Objectives This study aims to evaluate the radiation exposure to patients undergoing an abdominopelvic or a chest and abdominopelvic (trunk) CT examination and to assess compliance to imaging referral guidelines. Methods To this end, 357 standard abdominopelvic and trunk CT scans were collected from 8 Belgian institutions in 2011 and 2015. Effective dose (E) and collective dose were calculated using CT dose descriptors (CTDIvol and DLP), which were obtained from dose reports generated by the CT scanner. Subsequently, these CT requests were compared against the national referral guidelines to assess compliance. Population estimates for dose and compliance were obtained using multilevel linear regression and generalized estimating equation models. Results Between 2011 and 2015, a significant decrease of 28% in CTDIvol and DLP was found for abdominopelvic CT. The corresponding E decreased by 27%, and the collective dose by 23%. For trunk CT, a non-significant decrease of 6% was found in CTDIvol and a significant decrease of 14% in both DLP and E. However, the collective dose of trunk examinations increased by 39%. In 2011, 24% of the abdominopelvic examinations were not compliant with the guidelines, whereas this percentage dropped to 17% in 2015. Non-justified examinations accounted for 8% and 12% of all trunk CT scans in 2011 and 2015, respectively. Conclusion Between 2011 and 2015, there was a decrease in dose for patients undergoing abdominopelvic or trunk CT in Belgium. However, a fraction of the estimated doses are linked to unnecessary CT examinations, which should be avoided.

INTRODUCTION Cardiac catheterization procedures result in high patient radiation exposure and corresponding staff doses are reported to be among the highest for medical staff. The purpose of current randomized controlled study was to quantify the potential radiation dose reduction for both patient and staff, enabled by recent X-ray technology. This technology is equipped with advanced image processing algorithms, real-time dose monitoring, and an acquisition chain optimized for cardiac catheterization applications. METHODS A total of 122 adult patients were randomly assigned to one of two cath labs, either the reference X-ray modality (Allura Xper FD10, Philips Healthcare, the Netherlands) or the new X-ray system (AlluraClarity FD20/10 Philips Healthcare, the Netherlands). Exposure parameters and staff dosimeter readings were recorded for each exposure. Technical measurements were performed to define the radiation scatter behavior. RESULTS With the newer equipment, patient radiation dose is reduced (as total dose-area product) by 67% based on geometric means with 95%CI of 53%, 77% for diagnostic and interventional procedures. The C-arm and leg dosimeter readings were both reduced with 65% (P