Evaluation of radiation dosage in chest digital tomosynthesis

Objective: To evaluate the feasibility of chest digital tomosynthesis (DTS) for lung lesion screening by comparing the effective dose of chest DTS with chest digital radiography (DR), low-dose MSCT and MSCT examinations. Methods: The Fluke lung/chest phantom underwent posterior-anterior (PA), left lateral (LAT) chest DR and DTS with automatic exposure control technique. Using RTI DoseGuard and WinODS, the dose area product (DAP) and effective dose of PA, LAT and total DTS were calculated. CareDose technique was used for MSCT and low-dose MSCT scans, the dose length products (DLP) was acquired.According to the DLP to E (k) conversion coefficient in ICRP 103, the effective dose of low-dose MSCT and MSCT were calculated. Paired t test was used for comparison of the mean effective dose of DTS, DR and low-dose MSCT. Results: The mean effective dose was 0.13 mSv for chest DR and 0.11 mSv for DTS examination. The mean effective dose of low-dose MSCT and MSCT scans were 1.13 mSv and 6.38 mSv. The effective dose of chest DTS was comparable to that of chest DR, and was approximately 1/10 and 1/60 times lower than that of low-dose MSCT and MSCT scans. There was no statistical difference between chest DTS and DR (t=3.514, P>0.01), and there was a significant difference between chest DTS and low-dose MSCT (t=178.769, P<0.01). Conclusion: DTS is a new X-ray tomography which has the advantage of low radiation dosage in chest examination for lung lesion screening comparing with low-dose MSCT. (authors)