Program Information
Validation of An SSDE-To-Organ-Dose Calculation Methodology Developed for Pediatric CT in An Adult Population
H Mead1,2 , S Brady2*, R Kaufman2 , (1) Christian Brothers University, Memphis, TN, (2) St. Jude Children's Research Hospital, Memphis, TN
Presentations
MO-FG-CAMPUS-IeP2-3 (Monday, August 1, 2016) 5:00 PM - 5:30 PM Room: ePoster Theater
Purpose: To discover if a previously published methodology for estimating patient-specific organ dose in a pediatric population (5-55kg) is translatable to the adult sized patient population (> 55 kg).
Methods: An adult male anthropomorphic phantom was scanned with metal oxide semiconductor field effect transistor (MOSFET) dosimeters placed at 23 organ locations in the chest and abdominopelvic regions to determine absolute organ dose. Organ-dose-to-SSDE correlation factors were developed by dividing individual phantom organ doses by SSDE of the phantom; where SSDE was calculated at the center of the scan volume of the chest and abdomen/pelvis separately. Organ dose correlation factors developed in phantom were multiplied by 28 chest and 22 abdominopelvic patient SSDE values to estimate organ dose. The median patient weight from the CT examinations was 68.9 kg (range 57-87 kg), and median age was 17 years (range 13-28 years). Calculated organ dose estimates were compared to published Monte Carlo simulated patient and phantom results.
Results: Organ-dose-to-SSDE correlation was determined for a total of 23 organs in the chest and abdominopelvic regions. For organs fully covered by the scan volume, correlation in the chest (median 1.3; range 1.1-1.5) and abdominopelvic (median 0.9; range 0.7-1.0) was 1.0 ± 10%. For organs that extended beyond the scan volume (i.e. skin, bone marrow, and bone surface) correlation was determined to be a median of 0.3 (range 0.1-0.4). Calculated patient organ dose, using patient SSDE, agreed to better than 6% (chest) and 15% (abdominopelvic) to published values.
Conclusion: This study demonstrated that our previous published methodology for calculating organ dose using patient-specific SSDE for the chest and abdominopelvic regions is translatable to adult sized patients for organs fully covered by the scan volume.
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