Estimation of effective dose for pediatric total-body 18F-FDG PET/CT examination

3014 Objectives: To evaluate the effective dose of radiation received by children under whole-body 18F-FDG PET/CT examination in order to provide the evidence for optimum 18F-FDG PET/CT scan plan in pediatric patients. [Methods] Pediatric patients underwent total-body 18F-FDG PET/CT examinations at Sun Yat-sen University Cancer Center from July 2019 to April 2020 according to their medical procedure. Under the condition of automatic exposure, the effective dose of radiation produced by the total-body CT scan was estimated according to ICRP 102 with the dose length product (DLP) value and the effective dose of radiation produced by 18F-FDG was calculated according to the method recommended by ICRP 128. The total effective dose of radiation in 18F -FDG PET/CT were obtained by adding the above two doses. The children were divided into two groups according to their height (<100cm and ≥100cm), their body mass index (BMI) (normal and abnormal), the median of the body mass index (BSA) (low BSA and high BSA), and the age (<1 year old and ≥1 year old). The independent sample t test was applied to analyze the difference between the effective dose of PET and whole-body CT (EDPET+WBCT) of children in different groups. Results: A total of 84 children were enrolled in this study. The total effective dose (EDTOTAL) of total-body 18F-FDG PET/CT of children was 5.08~17.98 mSv, with the average (9.27±2.34) mSv. The effective dose (EDPET) produced by 18F-FDG PET was 2.91~8.03 mSv, with the average (4.71±1.16) mSv, the total effective CT dose (EDCT) was 1.65~13.86mSv with the average (4.56±2.00) mSv, and effective dose of whole-body CT (EDWBCT) was 1.65~6.76mSv with the average (3.73±1.04) mSv. In the subgroup analysis of different height, BMI, BSA and age group, EDPET+WBCT in the group of <1 year old was higher than that of ≥1year old (t=4.790, P<0.01). Conclusions: The effective dose of total-body 18F-FDG PET/CT in young children is larger than the old ones. The application of updating scanning equipment and technology can reduce the effective dose of 18F-FDG PET/CT in children. Key Words:18F-FDG PET/CT; children; effective dose;body surface area (BSA); body mass index (BMI)