SummaryWe have been engaged in clinical work using DSA, the first in the world, under a joint study agreement with Hitachi Medical Corporation on the use of the Flat Panel Detector FPD since 2001. We are now in the stage where a certain evaluation process has been finished, but the FPD performance study in angiography has just begun, and, therefore, its clinical evaluation results are very few. Therefore, we studied the relativity between clinical images and physical characteristics in order to examine the characteristics of FPD by referencing them to clinical images. We did an evaluation of the clinical images to which their physical characteristics such as granularity, resolution, contrast, etc., are reflected by comparing FPD and I.I. images.