Use of BMI Guidelines and Individual Dose Tracking to Minimize Radiation Exposure from Low-dose Helical Chest CT Scanning in a Lung Cancer Screening Program

Rationale and Objectives The increasing use of computed tomography (CT) has been accompanied by rising concerns over potential radiation-related health risks, especially cancer, and a need to minimize such risks. Materials and Methods We conducted 2186 low-dose helical chest CT scans among 1235 nuclear weapons workers at elevated risk of lung cancer, setting the CT scanner tube current at 30 mAs for all participants with BMI 25 kg/m2 and 37.1% exceeded a BMI ≥30 kg/m2 . Nearly 90% of CT scans were performed using a tube current setting of 30 mAs and had a mean DLP-based effective dose of 1.3 mSv. The phantom-based estimate of effective dose was lower at 1.1 mSv. Among participants with a BMI ≥35 kg/m2 , 92% were scanned at 40 or 50 mAs, which was associated with a DLP-based effective dose of 1.6 and 2.0 mSv, respectively. Image quality was satisfactory in 99.8% of scans. Conclusion Application of simple BMI-based guidelines and DLP tracking of low-dose helical chest CT scans in a lung cancer screening program minimizes radiation dose, even in a largely overweight population.