Abstract
Recent technical advances and a renewed interest in protection of patients against the danger of ionizing radiation have prompted new trends in interventional radiology. Therefore this paper presents a review on the state of the art in the field of both radiation doses and image quality optimization in interventional radiological procedures. After a summary of recent progresses in this area, an overview of physical parameters suitable for measuring the doses to patients in interventional radiology is introduced: indeed in these procedures both stochastic and deterministic risks have to be assessed, and then many “dose indicators” can be used (fluoroscopy time, dose-area-product, cumulative dose at the interventional reference point, etc.). Some National Authorities are transferring the principle of using reference levels of doses from plain film radiology to interventional examinations in order to optimize the procedures, and careful considerations have to be done about the very large variations in doses among different centres. Together with the dose issues, one must also consider the quality of the generated image: the three main image-quality physical parameters (i.e., contrast, sharpness, and noise) are interdependent, and therefore in interventional radiology the goal is to reduce the patient dose to the minimum level that will generate an image with an acceptable degree of noise, that is, to produce an “adequate” image, even if it is not a “perfect” image. Finally, a review of features available to optimize the full interventional procedure (image receptor, last image hold, pulsed fluoroscopy, spectral filtration, collimation, and virtual collimator) is given.
Keywords: Fluoroscopy, image quality, interventional radiology, patient dose, radiation protection
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