Program Information
Size-Specific Dose Estimates Correction in Adult and Pediatric Abdomen and Chest CT: A Retrospective Study
G Souza1, R Thomaz2, J Real3 , A Froner1, A Marques da Silva1 , (1) NIMed, PUCRS, Porto Alegre, Rio Grande do Sul, Brazil, (2) NANOPUC, PUCRS, Porto Alegre, Rio Grande do Sul, Brazil (3) HSL, PUCRS, Porto Alegre, Rio Grande do Sul, Brazil
Presentations
MO-RPM-GePD-I-5 (Monday, July 31, 2017) 3:45 PM - 4:15 PM Room: Imaging ePoster Lounge
Purpose: The aim of this study was to investigate retrospectively the CTDIvol (volume computed tomography dose index) variation when considering the dose corrected by specific size of the patient (SSDE) for chest and abdomen CT of pediatric and adult patients.
Methods: SSDE values were determined using CTDIvol and a conversion factor (f) based on the individual patient dimensions, obtained from the effective diameter measurements in CT images. The CT database were analyzed retrospectively, consisting of 30 adult and 40 pediatric patients chest scans, and 58 adult and 55 pediatric patients abdomen scans. The third quartile values were used for comparison between the CTDIvol and SSDE with the diagnostic reference levels (DRL) in the literature.
Results: Corrections for SSDE showed a 28.8% and 30.2% increase in the mean total dose for chest and abdomen scans for adult patients, respectively. For pediatric patients, there was an increase of 97.3% and 93.1% for chest and abdomen protocols, respectively. For pediatric chest CT, CTDIvol and SSDE were among DRLs, whilst for abdomen, SSDE was above all the DRLs used for this study. For adult chest examinations, CTDIvol and SSDE were below only one DRL, being above two DRLs. For adult abdomen, the CTDIvol and SSDE were above all the DRLs.
Conclusion: An increase in dose was observed when CTDIvol was corrected to SSDE, especially in pediatric patients. The phantom-size for CTDIvol calibration may have influenced on such dose increase. Therefore, although SSDE has shown to be a valid method, it is clear the need for continuous improvement and development of dose correction methods. Adequate phantoms for patients of different dimensions should be implemented.
Funding Support, Disclosures, and Conflict of Interest: FAPERGS
Contact Email: