National DRLs for adult body CT scans based on body width

s from the Irish Association of Physicists in Medicine 5th Annual Scientific Meeting Diagnostic Parallel Session Abstracts Assessment of clinical occupational dose reduction effect of a new interventional cardiology shield for radial access combined with a custom scatter reducing drape Paddy Gilligan , Jo Ann Lynch , Susan Maguire . Mater Private Hospital, Ireland; Dublin Institute of Technology, Ireland Introduction: Interventional cardiologists are high users of radiation. Access though the wrist or transradial access for cardiology interventions has been shown to increase occupational radiation dose, two to three fold. This is against a backdrop of increased concern regarding eye dose limits and radiation induced cataracts. Interventional laboratories have developed shielding techniques, primarily based on groin or femoral based access. Use of scatter reduction drapes, although they can be effective, has been limited due to concern around interference with automatic exposure control systems. This paper looks at the clinical occupational dose reduction effect of a custom designed by (access type), shield and drape. Materials and Methods: The evaluation took place in a busy interventional cardiology laboratory with a single plane 30 x 40 detector (Artis ZEE, Siemens, Erlangen). Collar doses, screening time and dose area product per case were monitored for a number of case types and operators using information from the unit and electronic personal dosimeters (Raysafe, Sweden): 1) Six months before 2) Onemonth immediately before and after and 3) during a one month deployment of the new shielding system. Results: The cardiologist dose was for most case types reduced significantly by the shielding arrangement. Some small increases in non-cardiologist doses were observed on initial analysis but these increases can be effectively remediated. The system was well accepted. National DRLs for adult body CT scans based on body width Dara Murphy , Michael Rowan , Sean Cournane , Una O'Connor , David Costello , Neil O'Hare . Our Lady’s Children’s Hospital, Crumlin, Ireland; Mater Misericordiae University Hospital, Ireland; c St. James Hospital, Ireland Background: To date CT Diagnostic Reference Levels (DRLs) have been set basedonnarrowpatientweight ranges (typically 60-80kg) and small sample sizes (typically 10 or more); however, it is well-known that weight is poorly correlated with CT dose metrics. While all modern CT scanners employ automatic exposure control (AEC) tomodify tube outputbasedonavarietyof patient factors, including body width, AEC systems from different manufacturers can vary significantly in how they treat patients of different body habitus. This can be particularly evident in overweight and obese patients Method: In this study dose data from 19 CT scanners on the NIMIS system was captured by Radimetrics eXposureTM software over a 12-month period, allowing for the collation of a range of CT scanning parameters from all examinations, including CTDIvol, DLP and patient diameter. Accordingly, local and National DRLs were calculated based on body habitus, in this case, body width. Analysis was performed on the following exams across all centres: Thorax, Thorax-Abdomen-Pelvis, Abdomen, Abdomen-Pelvis, KUB and High-resolution Chest. Results/Conclusion: This is the first study of its kind for establishing patient diameter-specific DRLs, on a local and national level, in an adult population. Of particular note were the significant differences in CTDIvol and DLP, respectively, for larger patients (those of increased diameter) across the CT scanners, thus highlighting the importance of tracking diameter-based dose metrics. Furthermore, CT scanners of similar model and manufacturer also exhibited significant differences for larger patients Comparison of in-house development cylindrical and spherical anechoic target phantoms for performance testing of breast ultrasound scanners Jacinta E. Browne , Louise M. Cannon , Andrew J. Fagan . Dublin Institute of Technology, Ireland; CAMI, St. James Hospital & TCD, Ireland Adequate discrimination between breast ultrasound scanners and indeed imaging modes is not possible using current commercially available phantoms. This is mainly due to their relatively simple geometry and insufficiently challenging targets to modern scanners. The objective of this study was to compare cylindrical and spherical anechoic target phantoms of clinically relevant sizes and depths, and to use them to evaluate the imaging performance of a range of breast imaging scanners. Tissue mimicking materials with properties that optimally replicate the acoustic properties of breast anatomy were used to construct a range of anechoic target phantoms, containing either cylindrical or spherical cysts ranging in diameter from 1e4mm at 4 clinically relevant depths. A semi-automated program was developed for determining anechoic target detectability through a measure of the lesion-signal-to-noise-ratio. Five ultrasound scanners were evaluated using these phantoms using the breast pre-sets and different imaging modes. The 1mm spherical target was not detected by any of the scanners but the 1mm cylindrical target was detected in some cases. The 3 and 4mm targets were found to be the most useful for comparing the range of scanners and imaging modes tested. The full results of the study will be presented with reference to current commercial test phantoms. It was found that the 3mm spherical target was the most promising for current breast imaging systems because it showed the best differentiation between the different imaging modes and scanners; the 1 and 2mm spherical targets provide scope to challenge new higher-performance breast ultrasound scanners. Performance comparison of flat panel fluoroscopy systems from three vendors Patrick Kenny, Brenda Byrne. Mater Misericordiae University Hospital, Ireland For fluoroscopy examinations, radiologists are migrating from the traditional use of Image Intensifiers to Flat Panel digital detectors. As well as the reduction in image distortion, the reduction in veiling glare permits better low contrast detectability [1]. We were interested to investigate how three vendors manage the balance between image quality and patient dose. For all systems we measured the variation in image contrast, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and PMMA entrance surface dose rate (ESDR) for PMMA thicknesses of 5, 10, 15 & 20 cms. A GS2 Leeds TO was located centrally to generate contrast. We calculated the cost of the image quality parameters in terms of EDR. We