A Comparative Study of Image Quality and Radiation Dose with Changes in Tube Voltage and Current for a Digital Chest Radiography

Purpose: High-voltage techniques applicable for analog radiographs are usually used in digital radiographs. We compared the image quality of the different exposure conditions to produce conditions of high image quality and low radiation dose. Materials and Methods: The tube voltage ranged from 70 to 133 kV, whereas the tube current ranged from 2 to 6.3 mAs. The digital radiograph images of a chest phantom were obtained at each setting. We measured the radiation doses of each condition, and counted the visible test objects. The numbers of objects for each condition were compared with the standards used at our institution. Results: The standard settings were set at 133 kVp and 2 or 4 mAs. Compared to the image quality at 133 kVp and 2 mAs, the radiation dose was lowest at a setting of 109 kVp and 2 mAs. Compared to the image quality of 133 kVp and 4 mAs, the radiation dose was lowest at 109 kVp and 4 mAs. Conclusion: The results of our study suggest that radiation dose can be reduced without compromising image quality by a low-voltage technique in digitial radiography.