Estimate of organ radiation absorbed doses in clinical CT using the radiation treatment planning system

T Fujibuchi, N Funabashi, M Hashimoto, H Kato, M Kurokawa, H. M Deloar, E Kunieda, I Komuro and T. Sakae

Radiation Protection Dosimetry, 2010, 142(2-4), 174-183. DOI: 10.1093/rpd/ncq188

Abstract

Organ absorbed doses in computed tomography (CT) scans can be measured with anatomical phantoms but not inside the human body. In this study, a straightforward method was investigated to estimate organ doses in clinical CT using the radiation treatment planning system (RTPS) and compared them with experimental results of photoluminescence dosemeters (PLD). In a heterogeneous phantom, the average difference between PLD and RTPS values were –5.0 % for the body and 7.1 % for the lung. Using CT data, organ doses in 30 clinical cases were then calculated. There was a significant inverse correlation between the calculated values of organ doses and body mass index (BMI, correlation coefficients (r)=–0.69 (whole body), –0.80 (right lung), –0.81 (left lung), –0.76 (spinal cord), –0.74 (vertebra bone), –0.74 (heart), and –0.79 (oesophagus), all p < 0.01). An RTPS can be a simple and useful tool for estimating equivalent doses inside the human body, during whole-body CT scans.

ASCI-ID: 1126-342