Local diagnostic reference levels for paediatric chest computed tomography in Morocco

The present study aimed to establish the local diagnostic reference levels (LDRLs) for paediatric chest computed tomography examinations in Morocco. The data were collected retrospectively from three university hospitals during a two-year period. The proposed LDRLs were expressed in terms of volume CT dose index (CTDIvol), dose-length product (DLP) per series, DLP per procedure, and size-specific dose estimates (SSDE). The effective diameter method was used to estimate SSDE conversion factors based on the middle slice of the scan series. A total of 489 procedures were enrolled including 74% of multiphase scans and 26% of a single series. The LDRLs in terms of CTDIvol (mGy) were 9.5, 9.5, 9.8, and 10.3 for <1 year, 1-<5 years, 5-<10 years, and 10-<15 years age groups, respectively. The LDRLs in terms of DLP (mGy.cm) per series were 188, 243, 276, and 316. In terms of DLP (mGy.cm) per procedure were 373, 491, 583, and 633. The corresponding LDRLs in terms of SSDE (mGy) were 24.4, 21.1, 20.3, and 19 respectively for the four age groups. The findings shed light on higher values compared to international studies for all age groups included.