Room: Exhibit Hall | Forum 8
Purpose: Recently, digital tomosynthesis system have been actively investigated to reduce patient dose in medical imaging. Digital tomosynthesis system generally requires higher dose than general digital radiography. In this work, we present various beam modulation schemes for low-dose digital tomosynthesis, and compared effects of the various acquisition schemes on the image quality.
Methods: A prototype CDT system (LISTEM, Korea) and the LUNGMAN phantom (Kyoto Kagaku, Japan) with lung nodule were used in this study. A total of 81 projection data obtained through various beam modulation schemes over a 40Â° angular range and were reconstructed by FBP algorithm. Truncated projection data obtained by beam modulation were corrected using laplacian and inverse laplacian operator. Contrast noise ratios (CNRs) of lung nodule were calculated to evaluate the image quality depending on various acquisition schemes.
Results: The reconstructed images obtained by beam modulation methods showed enhanced contrast while reducing area dose. It is found that various beam modulation schemes affect the image quality. Among the beam modulation schemes we investigated, the bunched view acquisition (outer focused) have shown promising results. The reconstructed image obtained through the bunched view (outer focused) showed a CNR value increased by 63% over the conventional acquisition method.
Conclusion: In this study, we found that various beam modulation schemes in digital tomosynthesis system affect the image quality. In addition, we investigated the effect of beam modulation schemes on image quality. The bunched view (outer focused) showed the best image quality. It is also expected that the patient exposure dose can be reduced by modulating beam size in digital tomosynthesis system.
Funding Support, Disclosures, and Conflict of Interest: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2017R1A2B2001818).
Tomosynthesis, ROI Fluoroscopy, Image Analysis