Objective: In our department, most high-resolution CT (HRCT) scans of the lungs are performed in conjunction with a standard helical examination to assess the entire chest. This requires scanning the patient twice. The goal of this study was to determine if the radiation dose could be decreased by performing a single combination helical scan of the chest from which both 5-mm standard and 1.25-mm HRCT images could be obtained.
Conclusion: Because the total measured radiation dose is 32% greater from a single combination helical HRCT scan of the chest versus separate standard helical plus axial HRCT scans, helical HRCT is not a clinically advisable technique.