REDUCTION OF RADIATION EXPOSURE WHILE MAINTAINING HIGH-QUALITY FLUOROSCOPIC IMAGES DURING INTERVENTIONAL CARDIOLOGY USING NOVEL X-RAY TUBE TECHNOLOGY WITH EXTRA BEAM FILTERING

Background Radiographic technology plays an integral role in intervent ional cardiology. The number of interventions continues to increase, a nd the associated radiation exposure to patients and personnel is of m ajor concern. This study was undertaken to determine whether a newly d eveloped x-ray tube deploying grid-switched pulsed fluoroscopy and ext ra beam filtering can achieve a reduction in radiation exposure while maintaining fluoroscopic images of high quality.Methods and Results Th ree fluoroscopic techniques were compared: continuous fluoroscopy, pul sed fluoroscopy, and a newly developed high-output pulsed fluoroscopy with extra filtering. To ascertain differences in the quality of image s and to determine differences in patient entrance and investigator ra diation exposure, the radiated volume curve was measured to determine the required high voltage levels (kV(peak)) for different object sizes for each fluoroscopic mode. The fluoroscopic data of 124 patient proc edures were combined. The data were analyzed for radiographic projecti ons, image intensifier field size, and x-ray tube kilovoltage levels ( kV(peak)). On the basis of this analysis, a reference procedure was co nstructed. The reference procedure was tested on a phantom or dummy pa tient by all three fluoroscopic modes. The phantom was so designed tha t the kilovoltage requirements for each projection were comparable to those needed for the average patient. Radiation exposure of the operat or and patient was measured during each mode. The patient entrance dos e was measured in air, and the operator dose was measured by 18 dosime ters on a dummy operator. Pulsed compared with continuous fluoroscopy could be performed with improved image quality at lower kilovoltages. The patient entrance dose was reduced by 21% and the operator dose by 54%. High-output pulsed fluoroscopy with extra beam filtering compared with continuous fluoroscopy improved the image quality, lowered the k ilovoltage requirements, and reduced the patient entrance dose by 55% and the operator dose by 69%. Conclusions High-output pulsed fluorosco py with a grid-switched tube and extra filtering improves the image qu ality and significantly reduces both the operator dose and patient dos e.