Diagnostic Reference Levels for Pediatric CT Examinations Based on Patient Size: A Meta-analysis

Background: Patient dose surveys are periodically performed to evaluate whether the patient’s doses are acceptable compared to the recommended and reported diagnostic reference levels (DRLs). Objectives: The current study aimed to explore the literature on existing size-specific DRLs and determine radiation dose metrics in pediatric computed tomography (CT) examinations. Methods: The systematic literature search was carried out using Web of Science, PubMed, Embase, and Scopus databases, and the Google Scholar search engine until May ۲۰۲۴. Based on the definition of a child, an age limit of up to ۱۸ years was applied to the age of the study participants, and publications investigating only DRLs for pediatric CT examinations were included. The exclusion criteria were as follows: ۱) Studies that reported DRL values for imaging modalities other than CT. ۲) The age of participants for whom DRL values were reported exceeded the age limit defined for children. ۳) Studies that did not provide sufficient data to calculate the Mean±SD for radiation dose metrics. The Mean±SD of radiation dose metrics were used to determine the overall effect size. The metan package developed in STATA software, version ۱۶.۰, was used for data analysis.  Results: This study retrieved a total number of ۴۷۶۱ patients undergoing pediatric CT examinations. For all radiation dose metrics in five groups of effective diameters, the P obtained from the χ۲ test of heterogeneity was <۰.۰۰۱. Moreover, the I۲ tests for all studies ranged from ۹۴.۳% to ۱۰۰%. Therefore, the random-effects model of the meta-analysis was used for the studies. The pooled estimates for CTDIvol/DLP/SSDE in patients with effective diameters of <۱۵ cm, ۱۵-۱۹ cm, ۲۰-۲۴ cm, ۲۵-۲۹ cm, and ≥۳۰ cm were calculated as ۱.۸۹ mGy/۳۴.۵۲ mGy.cm/۴.۲۴ mGy, ۳.۳۱ mGy/۱۲۶.۰۳ mGy.cm/۵.۲۳ mGy, ۴.۴۹ mGy/۱۷۰.۷۴ mGy.cm/۶.۶۱ mGy, ۳.۷۸ mGy/-/۵.۲۹ mGy, and -/-/۷.۵۲ mGy, respectively. The shapes of Begg’s funnel plots were considered to be moderately asymmetrical, which demonstrated the publication bias in the reports. The reported estimates for radiation dose metrics were generally higher than those recommended by the European Commission. The pooled estimates for the radiation dose metrics increased with the effective diameters of the patients, and the study location significantly modified the radiation dose metrics (P<۰.۰۰۱). Conclusions: The results indicated that the pooled estimates for radiation dose metrics of pediatric chest CT examinations were generally higher than the recommended limits, and the pediatric chest CT protocols must be reviewed and optimized worldwide.

کلیدواژه ها:

Diagnostic reference level (DRL) ، Computed tomography (CT) ، Pediatrics ، Radiation dose