Abstract:
Background: Computed Tomography (CT) is essential in diagnostic imaging but delivers higher
patient doses compared to conventional x-ray examinations. According to the International
Commission on Radiological Protection (ICRP) publication 135, the typical patient dose (median
value) can be used to optimize patient doses at the institutional level.
Objective: To propose typical patient dose values for adult patients undergoing routine chest CT
examinations at Teaching Hospital Peradeniya, Sri Lanka
Methods: This retrospective, cross-sectional study was conducted from June to December 2023.
A total of 262 CT dose reports from adult patients (18-88 years) were analyzed to extract patient
dose indicators; volumetric CT dose index (CTDIvol) and dose-length product (DLP).
Results: The proposed typical patient dose values for CTDIvol and DLP were: for non-contrast CT
(NCCT) chest, 9.00 mGy and 281.54 mGy.cm, and for contrast-enhanced CT (CECT) chest, 9.21
mGy and 367.87 mGy.cm, respectively. Compared to reported values from six countries, the
proposed CTDIvol for NCCT chest was higher by 84% in Singapore, 72% in Saudi Arabia, and
61% in South Australia, however, lower by 8% in Indonesia and 29% in Morocco. Similarly, the
proposed DLP for NCCT chest was higher by 70% in Singapore, 96% in Pakistan, 70% in Saudi
Arabia, and 69% in South Australia, but lower by 24% in Indonesia and 48% in Morocco. Typical
CTDIvol values in this study were higher than previously reported values in Sri Lanka: 9.0 vs 7.4
mGy for the NCCT chest and 9.2 vs 8.3 mGy for the CECT chest. However, typical DLP values
were comparable to those previously reported.
Conclusions: The typical patient dose values in this study are higher compared to literature
values, indicating a need for dose optimization in chest CT examinations. These proposed values
can help to improve current examination protocols at Teaching Hospital Peradeniya, Sri Lanka.
