Dose Optimization in Cardiovascular Interventional Radiology

The thesis treat the patient dose optimization in Carbon Dioxide Angiography and dose reduction with the using of Clarity Philips in EP procedures. Carbon dioxide angiography is based on the visualization (i.e., the radiographic contrast) of gas bubbles injected in blood vessels. By using an experimental X-ray bench, it has been measured the energy response of a flat panel detector (Varian CB4030) and, with a dedicated phantom and a software simulation, the image contrast of vessels injected with Iodine and CO2. The results show that the contrast generated by carbon dioxide is about one fourth of that obtained with iodine, demonstrating that CO2 angiography should use different radiological settings with respect to iodine angiography. In particular, a kVp increase have a lower reduction of CNR with carbon dioxide than with iodinated CM, suggesting possible technological improvements in fluoroscopy protocols. The aim of the second work has been to evaluate the patient dose comparison between before and after the introduction of the Philips Clarity system upgrade. The retrospective study has been made on 561 procedures of pacemaker (PM) and implantable cardioverter defibrillator (ICD) implantations (134 pre, 192 post), and 235 procedures of radio frequency ablation (RFA) procedures (91 pre, 144 post). The pre and post sets are compared over clinical details in order to define an average patient for each intervention type. Each procedure has been studied over single irradiation event collected in the Structure Dose Report (SDR). The Dose-Area Product (PkA) cumulative quantities is not normal distributed over a single procedure type, so a log-normal hypothesis has been made. The results shows a significant reduction of the for the PkA equal to 54% over all the procedures. The total fluoroscopy time didn’t change appreciably and this shows in first instance that that the subjective image quality didn't change too.