RESUMO
PURPOSE: To evaluate the effect of dose reduction on image quality in digital radiography using a flat-panel detector. MATERIALS AND METHODS: Digital radiographs of 30 rabbits were obtained at two different dose levels (33.23 µGy for the standard dose group and 20.09 µGy for the reduced dose group). The amorphous selenium-based flat-panel detector system had a panel size of 7x8.5 inches, a matrix of 1280x1536 (pixels?), and a pixel pitch of 138 µm. Four observers evaluated the soft-copy images on a high-resolution video monitor (2560x2048x8 bits) in random order. The observers rated the visibility of 13 different anatomic structures on a 5-point scale, viz. the retrocardiac lung, subdiaphragmatic lung, heart border, diaphragmatic border, proximal airway, unobscured lung, liver border, kidney border, bowel gas, flank stripe, ribs, and vertebrae in the mediastinal and abdominal regions. Statistical significance was determined using Wilcoxon's signed rank test. RESULTS: There was no statistically significant difference in the visibility of the anatomic structures on digital radiography between the standard and reduced dose groups. CONCLUSION: Digital radiography using an amorphous selenium-based flat-panel detector can preserve the image quality, even though the does is reduced to 40% of the standard level.