A rotational digital angiography system was newly developed by authors. During the rotation, a pulse exposure is done at every 1.25 degrees by computer control, so that 288 different projectional images can be acquired following a single injection of contrast medium. Because rotational image data can be easily reconstructed to 3-D images, more useful diagnostic informations are obtained. Rotational digital angiography was performed for 15 patients with acute pulmonary thromboembolism, and massive thromboemboli were revealed in all patients. The diagnostic usefulness of this new system has also proven to be improved in the interventional procedures. At the appropriate angle, the thrombosed vessels were clearly distinguished. Thus, as the tip of the catheter was advanced to the target site, the thrombosed lesion could be exclusively treated by interventional techniques. The device has, therefore, been found to be of great value in the diagnosis and intervention of acute pulmonary thromboembolism.