Abstract: This study investigated the radiation dose distribution of children′s CT scans in a hospital in Nanjing, with the aim of understanding the radiation dose levels of pediatric subjects in the hospital′s CT examinations and providing a basis for exploring and establishing the diagnostic reference level (DRL) for children′s CT examinations in this hospital. This study retrospectively collected basic information and CT imaging data of pediatric subjects who underwent CT diagnosis at the hospital from 2020 to 2024. Three examination sites, namely the head, chest, and abdomen, were collected, and the subjects were divided into four age groups according to age<1, 1~<5, 5~<10, and 10~≤ 15 years old. The differences in dose distribution between different age groups in the same site were analyzed; At the same time, this article used the median(P₅₀) of CTDI_vol and DLP as dose reference levels to compare with other regions. The median values(P₅₀) of CTDI_vol and DLP at the corresponding examination sites in the four age groups of<1~<5, 5~<10, 10~≤ 15 years old were as follows: head: 4.3, 6.9, 7.4, 8.2 mGy and 78.9, 143.3, 153.5, 173.0 mGy·cm; Chest: 1.7, 2.1, 3.4, 4.1 mGy and 32.9, 50.9, 90.2, 131.7 mGy·cm; Abdomen: 2.2, 3.8, 4.2, 5.7 mGy and 55.8, 137.5, 175.0, 290.1 mGy·cm. Among them, there were statistically significant differences in CTDI_vol and DLP between different age groups of the same body part (head, chest, and abdomen, CTDI_vol:χ²=173.47,199.91,158.91; DLP:χ²=186.73,265.97,210.99,P<0.001). The P₅₀ digits of CTDI_vol and DLP in various body parts of pediatric patients in this hospital are generally lower than the national level, However, there are still some examinees whose CTDI_vol and DLP are higher than DRL cited in GBZ 130—2020. Therefore, it is necessary to further optimize the CT scanning program.

Key words: children, CT, radiation dose, diagnostic reference level