Purpose: To investigate the usefulness of helical CT with low-dose and single-breath-hold scanning for lung cancer screening.
Materials and methods: Twenty-four helical CT scans of the lung were performed using various parameters in 10 healthy volunteers. The effects of tube current and pitch were evaluated by assessment of image quality and detection of simulated nodules. Screening helical CT was performed at 120 kVp, 50 mA, 1 sec/rotation, 10 mm collimation, and a pitch of 2.0 in 110 patients. The ability of this method to detect nodules and masses, focal parenchymal opacities, and diffuse fibrotic changes was evaluated using conventional CT as the gold standard.
Results: A reduction in tube current to 50 mA did not significantly change the assessment of image quality or detection of simulated nodules. Although these factors were degraded by increasing the pitch, there was no significant difference between 1.5 and 2.0. Screening helical CT permitted the entire lung to be scanned with ease during a single-breath-hold in all patients. This method detected 177 of 196 nodules and masses (87 of 91 lesions greater than 5 mm in diameter), 54 of 57 focal parenchymal opacities, and 15 of 15 cases with fibrotic changes.
Conclusion: Screening helical CT with low-dose and single-breath-hold scanning shows promise for lung cancer screening.