Dennise Magill

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PURPOSE To generate effective dose per unit dose length product (E/DLP) conversion factors incorporating ICRP Publication 103 tissue weighting factors. METHODS Effective doses for CT examinations were obtained using the IMPACT Dosimetry Calculator using all 23 dose data sets that are offered by this spreadsheet. CT examinations were simulated for scans(More)
PURPOSE To investigate how x-ray tube projection angle affects organ and effective doses to patients undergoing a CT examination on a cone beam scanner. METHODS The authors investigated two cone beam CT systems that use a flat panel detector to capture the x-ray pattern transmitted through patients. One system had the flat panel detector and x-ray tube(More)
Both air and radiopaque liquid contrast are used to reduce ileocolic intussusception under fluoroscopy. Some suggest air lowers radiation dose due to shorter procedure times. However, air enema likely lowers radiation dose regardless of fluoroscopy time due to less density over the automatic exposure control cells. We test the hypothesis that air enema(More)
The aim of the study was to investigate how differences in patient anatomy and CT technical factors in neck CT impact on thyroid doses and the corresponding carcinogenic risks. The CTDIvol and dose-length product used in 11 consecutive neck CT studies, as well as data on automatic exposure control (AEC) tube current variation(s) from the image DICOM header,(More)
PURPOSE To describe a method for estimating absorbed doses to the thyroid in patients undergoing neck CT examinations. METHODS Thyroid doses in anthropomorphic phantoms were obtained for all 23 scanner dosimetry data sets in the ImPACT CT patient dosimetry calculator. Values of relative thyroid dose [R(thy)(L)], defined as the thyroid dose for a given(More)
The aim of the study was to investigate how patient effective doses vary as a function of X-ray tube projection angle, as well as the patient long axis, and quantify how X-ray tube current modulation affects patient doses in chest CT examinations. Chest examinations were simulated for a gantry CT scanner geometry with projections acquired for a beam width(More)
OBJECTIVES To investigate the relationship in dental Cone-Beam CT (CBCT) between the manufacturer-reported image pixel data and a modified conversion to CT number densities in Hounsfield Units (HU). METHODS A standardized CT phantom was imaged using typical clinical parameters on CBCT from 3 manufacturers (Carestream 9300®, J Morita 3D Accutomo®, and(More)
Gonadal shielding remains common, but current estimates of gonadal radiation risk are lower than estimated risks to colon and stomach. A female gonadal shield may attenuate active automatic exposure control (AEC) sensors, resulting in increased dose to colon and stomach as well as to ovaries outside the shielded area. We assess changes in dose–area product(More)
Cardiac catheterisation personnel are exposed to occupational radiation and its health risks. Little data exist regarding the efficacy of radiation-protective equipment from congenital catheterisation laboratories (CLs). The authors retrospectively reviewed data in which CL operators wore a radiation dosemeter during catheterizations on patients of >20 kg.(More)
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