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.

In the dismantling work of glove boxes (GBs) contaminated with radioactive materials at the nuclear fuel facilities, plastic tents are constructed around the entire GBs, and workers putting on air-fed suits (AFS) (hereinafter referred to as AFS worker) dismantle the GBs and interior equipment by using cutting tools. If an AFS worker suddenly feels sick during the work and the worker is unable to move independently, it will be necessary to exit in the shortest time from the viewpoint of respecting human life. In this case, a lot of radioactive materials may be brought into the contamination control room, thus the room and the equipment of the workers may be contaminated. Consequently, until the decontamination work is completed, the other AFS workers will have to put on AFS and wait for long time, which puts a strain on the workers. In this report, the plastic enclosure tents for body decontamination developed in JAEA were used as a new contamination control room replaced the contaminated one, and the procedure to quickly exit the remaining AFS workers was proposed. As a result, we confirmed that it was possible to greatly reduce the waiting time of the other AFS workers who were forced to wait in the dismantling area.