Background/Objectives: The purpose of this study is to improve the image quality and minimize the exposure dose that the patient receives by changing the source to image distance (SID) during the lateral examination of sternum in general examinations. Methods/Statistical analysis: The study used digital radiography (DR) system and manikin chest phantom. To describe the sternum lateral view, the phantom was examined in the true lateral position. The examination parameters were adjusted to 75, 85, 95 kVp of tube voltage and 11, 16, 20, 25, 32, 40, 50 mAs of tube current, 130, 180cm of SID. As for the filter, the study used Non-filter, 1 mmAl filter, 1 mmAl + 0.1mmCu composite filter. For dose assessment, the study measured entrance surface dose (ESD) and dose area product (DAP) for each setting, and calculated signal to noise ratio (SNR) and contrast to noise ratio (CNR) for image quality assessment. Findings: As the result, based on proper exposure index (EI) value, 180cm SID and 85 kVp, 25 mAs, non-filter setting, the ESD was 0.91 mGy and DAP was 88.2 Gycm2.