The specific aim of the proposed project is to alter and complete an existing prototype Rotating Aperture Wheel (RAW) device so as to be able to do extensive tests as well as give the first clinical demonstration of its use. The development of the RAW technology which is proposed involves replacing a grid for scatter elimination with an assembly of one coder and two discriminator lead aperture wheels. These are rotated so as to maintain the alignment between the slit and/or hole pattern of each. Such a design has the unique feature that its motion can be made independent of the x-ray exposure time and duration allowing for the first time the practical use of a moving slit anti-scatter technique with the advantages of reduced dose and improved subject contrast in dynamic, rapid sequence, as well as fast single frame static radiographic procedures. The technology is flexible so as to lend itself to use with varying source to image receptor distances such as is involved in fluoroscopy as well as to conventional tomography. Among those areas where the RAW technology may be beneficial are abdominal and neuro angiography, cardiac cineradiology, and fluoroscopic procedures including spot filming such as barium enema, GI series, cholecystography, cholangiography, and others. In addition, the RAW technology appears directly applicable to digital radiography and digital fluoroscopy. It appears that those radiographic procedures which involve the highest individual patient dose and the highest genetically significant dose burden to the population and where the greatest radiographic contrast may be required are just those procedures which, of the multiple slit methods, only the RAW method can be directly applied. While commercial equipment manufacturers appear to be interested in developments in multiple slit radiography, none has publicly announced significant device development programs. A prototype clinical RAW device with many of the physical and technical problems considered and/or resolved should encourage this much needed development and eventual wide-spread distribution.
