Dose reduction in chest CT examination.

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.