Computed tomography (CT) examinations involve relatively high doses to patients. The objectives of this study were to optimise the radiation dose for patient during CT chest scan and to estimate the lifetime cancer risk. A total of 50 patients were studied: control group (A) (38 patients) and optimisation group (B) (12 patients). The optimisation protocol was based on CT pitch increment and lowering tube current. The mean volume CT dose index (CTDI vol) was 21.17 mGy and dose length product (DLP) was 839.0 mGy cm for Group A, and CTDI vol was 8.3 mGy and DLP was 339.7 for Group B. The overall cancer risk was estimated to be 8.0 and 3.0 cancer incidence per million for Groups A and B, respectively. The patient dose optimisation during CT chest was investigated. Lowering tube current and pitch increment achieved a radiation dose reduction of up to 60 % without compromising the diagnostic findings.

Background: Worldwide the computed tomography (CT) scanning is recognized as a high radiation dose modality. This article aimed to estimate the radiation dose reduction and radiogenic risks for adult patients undertaking abdominal CT examinations. Materials and Methods: A total of 128 patients were studied using 2, 4, 16 and 64 slice CT scanners. The patients were divided into two categories: the first category as control category (80 patients), and the other as optimisation category (48 patients). The optimisation protocol was based on decreasing the gantry rotation time. Results: In general, the faster gantry rotation times (0.7 s/rot and 0.5 s/rot) resulted in dose reduction while maintaining images noise within the acceptable range. After dose optimization, the overall cancer risk was reduced by 21%, 49%, 29%, and 16%, for the patients undergoing abdominal examinations on 2, 4, 16 and 64 slice CT scanners, respectively. Conclusion:The patient dose optimisation during CT abdomen was investigated. By lowering gantry rotation time, a radiation dose reduction of up to 30 % was achieved without compromising the diagnostic findings. Accordingly, the attention of all technologists necessary to take advantage of the dose reduction methods reported in this study.