Cancer imaging by scanned projection radiography

We have evaluated scanned projection radiography (SPR) for the diagnosis of cancer. Four rabbits with V2 thigh carcinomas and nine patients with a variety of malignant neoplasms were studied with a GE CT/T 8800 scanner modified for SPR. Images were made before injection of intravenous contrast medium, and additional scans were taken after injection. Temporal subtraction was then performed on the digitized data. Rabbit thigh V2 carcinomas and human lung, liver, and extremity neoplasms were visualized. Contrast enhancement was phasic with early vessel demonstration and subsequent visualization of low density central areas of tumoral necrosis. Liver metastases appeared as poorly defined areas of low density. Because of the combination of high contrast sensitivity plus capability of imaging large tissue volumes on one scan, SPR may be valuable in cancer screening.