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Direct Organ Dose Measurement for Multi-Detector Computed Tomography Utilizing Cadaveric Subjects

Lindsay Sinclair

L Sinclair1*, A Mench1, T Griglock2, B Cormack1, S Bidari1, M Arreola1, (1) University of Florida, Gainesville, FL (2) Oregon Health and Science University, Portland, OR

MO-B-Salon EF-8 Monday 10:00:00 AM - 12:00:00 PM Room: Salon EF

Purpose: While CT has allowed for great advances in the field of diagnostic imaging, this progression has not ensued without careful attention to the radiation dose associated with its use. There remains a critical need to accurately assess organ doses resulting from these procedures. This research aims to directly measure organ doses by utilizing cadaveric subjects.
Methods:Techniques in a CT exam are tailored according to patient size and scanner-specific parameters. To account for this, four cadaveric subjects of body mass indices (BMI) ranging from 17 to 49 (BMI) were utilized for direct organ dose measurement on a 320-slice CT scanner. A dosimeter placement system was previously developed which utilizes optically-stimulated luminescent dosimeters (OSLDs). The OSLDs were placed on the skin and within the following organs: thyroid, lungs, breasts, liver, stomach, small intestine, large intestine, uterus, and ovaries. The location and number of dosimeters were based on the size and distribution of each organ, with a maximum of 48 dosimeters used for each scan. A variety of clinically-accepted CT protocols was examined, including chest (C), abdomen (A), pelvis (P), CAP, 3-phase liver, pulmonary embolism, and trauma protocols.
Results:Average and maximum organ doses were recorded for each exam. For a CAP exam, average organ doses for all subjects ranged from 8-26 mGy for organs in the primary beam. The highest organ doses were observed in the two subjects that classified as obese, with BMIs over 30.
Conclusion:Direct organ dose measurement resulting from CT exams is possible and has been completed for a range of representative adult patient sizes and clinical protocols with this research. This methodology can be extended to any CT scanner, protocol, or patient size, resulting in more accurate dose data. Additionally, these directly measured organ doses can be compared to estimated values obtained from other methodologies.

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