A comparison of computational methods for estimation of effective and organ doses to the patients from CT examination

Abstract

The current study was devoted to estimation of effective and organ doses to the patients from the most common computed tomography (CT) examinations: head, chest, abdomen, chest+abdomen+pelvis in advanced scanners. Doses were estimated using dedicated software (CT-Expo, XCATdose, and NCICT) and conversion coefficients from the dose length product (DLP) to the effective dose according to Methodicalguidance 2.6.1.2944-11 “Assessment of effective dose to the patients undergoing X-ray examinations”. Results of the estimation of organ doses using tested software programs showed a lack of significant differences. Overall, 98% of organ doses estimated by each software program had a less than 20% difference compared with the average value of doses estimated by each software and 71% had less than 10% difference. Comparison of organ doses estimated for voxel and mathematical (MIRD-5) phantoms showed a difference up to 22%. The overestimation with a factor of two, in comparison with the software codes, was observed only for effective dose for the CT examination of a head determined according to existing guidelines. For other examinations, the differences in effective doses were insignificant. The effective dose assessed according to existing guidelines can be used to fill the report forms or rough risk estimate for justification of CT examinations.

Keywords

• компьютерная томография
• эффективная доза
• органная доза
• произведение дозы на длину сканирования
• антропоморфные фантомы