Digital videofluorography: a new direction in diagnostic imaging.

Accurate information about digital technology is often difficult to obtain because of unrealistic expectations. The development of the digital department is complex and must not be understated. However, we have attempted to show that if a truly committed hospital immediately accepts DVF, this will result in reduced capital and operational costs, as well as lower radiation doses to the patient and operator. We believe this will happen because every major X-ray manufacturer is demonstrating and offering DVF systems, all of which are based on the technology described in this paper. These systems can either be totally integrated into fluoroscopic facilities or be purchased as add-on components to established units. In any event, a modern fluoroscopic facility can cost several hundred thousand dollars, and must last 10 to 15 years. It seems prudent to acquire quality and digital capability so that these units will be adequate in the year 2000 and beyond.

Clinical comparison of analog and digital 100 mm photofluorography.

Many of the problems associated with digital acquisition of clinical images from x-ray intensifier/television systems have been eliminated by the use of a pulsed progressive readout from a 1024 line television camera into a 1024 x 1024 pixel image store, the whole arrangement triggered by the circuitry of a 100 mm camera. By means of a beam splitter, this study demonstrates a clinical comparability between 100 mm and digital images under identical conditions. In addition, radiation dose levels can be reduced by tailoring exposures to individual patients and their clinical needs. Several clinical cases are presented to illustrate the interchangeability of the new digital modality for fluoroscopic examination with an ordinary sized x-ray image intensifier.

System for digital acquisition of gastrointestinal images.

Previous theoretical work and clinical experience with digital acquisition of fluoroscopic images have identified several problems which needed to be solved. These are: image resolution; blurring due to patient motion, combined with long exposure times; and excessive x-ray quantum mottle levels. We will show that application of pulsed progressive readout (PPR) methods to the TV camera solves these problems. By permitting a high-intensity x-ray pulse to be delivered, all motion is stopped and quantum mottle is reduced to acceptable levels. It will be shown that 1024 x 1024 digital matrices provide adequate resolution and 8-bit digitization is sufficient to permit the same quality as is used in conventional 100-mm photofluorography. User acceptance can be made easier by incorporation of existing photofluorographic controls (with which the radiologist is already familiar) to acquire the digital images. It is possible to interface PPR video systems using existing 100-mm exposure circuits without much modification and the resulting system can be regarded as a digital 100-mm camera.

Videofluorography and pulsed fluoroscopy using a 512 X 512-pixel digital image system.

The combination of videofluorography and pulsed fluoroscopy using an analog videodisc system has previously been investigated with regard to image quality and potential for dose reduction. The authors found that the system could be improved still further by replacing the analog disc with a 512 X 512-pixel digital image system, thereby increasing fluoroscopic image quality and permitting stored images to be recorded with a multiformat camera. The pulsed method is compared with low-dose-rate fluoroscopy, in which a continuous image is obtained at 1/4 of the normal rate. Whereas image quality using a low dose rate was inadequate for any useful purpose, pulsed fluoroscopy was sufficient for all but the most critical stages of the examination.

Radiation dose implications of digital angiographic systems.

Digital subtraction angiography (DSA) has been widely accepted and applied. The concentration of iodine in the vessels of interest is low in intravenous DSA. The resultant images can be improved to some extent by increasing the radiation dose. Therefore DSA could become, and possibly could remain, a relatively high-dose procedure. The contributions to dose from the various components of the examination such as fluoroscopy, positioning, test exposures, and final acquisition runs are considered separately. Individual segments of a DSA examination are discussed to show how and where opportunities arise to reduce doses to the lowest levels consistent with satisfactory images.

Multi-image camera for spot radiography at fluoroscopic examinations.

The image quality of photofluorographic spot films (70, 100 or 105mm) has bee gradually improving as high resolution image intensification has evolved. With newly available 1023-line fluoroscopic monitors providing 2.8 line pairs/mm resolution, it is now possible to photograph diagnostic images directly off the monitor. Such images provide detail similar to that currently available on 100mm spot films. A multi-image camera has been modified to record spot films from the video disc image resulting in marked reduction in patient radiation and film cost. Initial findings incorporating pulsed fluoroscopy using a video disc are discussed.

Radiographic, photofluorographic, and television imaging systems: an evaluation.

A feasibility study for the photographic recording of fluoroscopic images from a high resolution system is described. Resolution on the television monitor was 2 line pairs/mm, making clinically acceptable recordings possible. Significant reductions in radiation dose to the patient and potential financial savings are indicated if a multiformat camera is developed to photograph the monitor.