Correction of image distortion for stereotactic DSA localization

In order to perform stereotactic localization in digital subtracted angiography, we present a method of correcting the distortions of an image intensifier (II) by a calibration grid. A test pattern is used to study the effectiveness of the corrections. The results obtained demonstrate the accuracy of the correction provided that the apparatus is warm. The long-range drift of the distortion is also considered. This paper demonstrates that geometrical distortions have to be corrected if the II is used for stereotactic localization and that a warm apparatus is essential for successful correction of distortions