2022 年 57 巻 2 号 p. 87-92
Background and purpose: The Japanese dose-length product (Japanese-DLP) method is currently being developed for calculation of CT shielding. The purpose of this study is to verify the Japanese-DLP method. Methods: Scattered dose in the CT room was measured during CT of the head, body, and limbs of a human body phantom under standard imaging conditions, and compared with radiation dose calculated using the Japanese-DLP method. Results: The minimum calculated/measured ratios were 2.0 and 4.7 for the head and body, respectively. The minimum value of the calculated/measured ratio of the limbs was 1.9 when the head air kerma scatter factor (AKSF) was used and 7.4 when the body AKSF was used. The calculated radiation dose was overestimated using the body AKSF, which could be reduced to half. In addition, it was possible to use the head AKSF for the limbs. Conclusions: The body AKSF did not underestimate the scattered dose and could be reduced to half (3.0 × 10–4) the current level. Use of the head AKSF for the limbs did not result in underestimated values.
