The use of rotascanography for peripheral vascular angiography.

Abstract

Rotascanography, a method of scanning a length of film by rotating the X-ray tube about its focal axis during exposure, was described by Watson (1962). If the X-ray tube used is mounted on a pivot which is coaxial with the focus on at least one axis, rotation of the tube on this axis will cause no movement of the focus. Therefore, each part of the image will always be projected on to the same part of the film, even if the tube is rotated during exposure. A similar method, slit scanography, has been used for arteriography (Astle, Wallace and Jones, 1953). We have not tried this method, but in theory rotascanography should give better definition and also any size of diaphragm opening can be used. We tried this method of radiography while waiting to obtain a cassette changer. It proved to be a simple method of obtaining films during femoral arteriography and aortography for peripheral vascular disease. We found it easier than changing films by hand through a cassette tunnel and therefore thought that our experience might be of interest to those without special apparatus. A cassette tunnel stretching the length of the table was covered by a plastic foam mattress. Using a floor mounted overcouch tube, the tomograph arm was attached to the tube support to act as a lever. The tube was fixed at 48 in. above the table top and freed so as to be able to rotate longtitudinally with relation to the table.