モンテカルロ計算用X線CT線源の汎用化に関する研究

[Purpose]WAZA-ARI is the web-based open system for X-ray CT dose calculator, which has been developed by NIRS and Oita University of Nursing and Health Sciences and the Japan Atomic Energy Agency. The organ doses in CT scan were calculated using Monte Carlo simulation. We constructed source models based on actual measurements. The selectable CT scanners in WAZA-ARI are still not enough despite the continuing addition of CT scanners because the CT developers deliver a steady stream of new products. In this study, we investigate the general models of CT sources by categorizing exiting sources.[Methods]The organ doses in CT exposure depend on radiation quality and fluence distribution of X-ray. This information of each scanner was measured using ionization chamber and GafChromic film. We categorized CT sources based on parameter of radiation quality and fluence distribution for many CT scanner.[Results]Using the total quality equivalent filtration (TQEF) and full width at half maximum (FWHM) of dose distribution, 16 CT sources were categorized. By dividing these sources into 2 groups based FWHM, there was a significant correlation between TQEF and effective dose in typical scan conditions.[Conclusion]CT sources were categorized using TQEF and FWHM of distribution. From these results, most sources of CT scanners can be expressed using several general sources.第113回日本医学物理学会学術大