Trigger Levels Impact of Radiation in Radiological and Cardiological Interventions

Abstract

The present study analyzed the feasibility of setting trigger levels to evaluate for probable deterministic effects from complex fluoroscopic guided Radiological and Cardiological interventions. Various aspects including fluoroscopic techniques, patient dosimetry, the effect of radiation dose from various angiographic projections, effective dose and risk of exposure induced death were assessed during the study. This data was useful in setting up guidance levels, trigger time and risk charts for all interventions. The complex interventions which reached 2 Gy (alert level I for deterministic effect) were triple vessel PTCA, spinal angiography, cerebral embolization and TIPSS with Ka, r higher than 2 - 3 Gy. The study also compared radiation dose from image intensifier (II), an older flat detector (FD) and novel flat FD with real-time noise reduction. Radiation dose using optimized settings in II system and older FD systems were similar without significant difference. However, the novel FD systems were able to reduce dose up to 40 to 50% as seen in this study as well as reported in the literature. The significant dose reduction would be possible in novel FD systems when stringent optimization is applied as reported in our study. Radiation dose from cardiological interventions performed using Philips Xper (older FD system) was 2 times higher than Philips Clarity (novel FD system) due to increase in exposure factors and dose rates. The Xper system with standard image processing demonstrated an increase in image noise during clinical practice compared to Clarity system with real-time noise reduction. Increased image noise also resulted in higher fluoroscopic screening time leading to an increase in radiation dose. The system with real-time noise reduction enabled interventions to be performed using lower newlineexposure rates without compromising on image quality. The study introduced a method for setting up trigger levels based on dose rates displayed on the viewing monitor when interventions are being performed.