EXPERIMENTAL DETERMINATION OF BLURRING IN X-RAY FLUOROSCOPYLAST IMAGE HOLD DUE TO PATIENT MOVEMENT ANDITS REPERCUSSION TO PATIENT DOSES

摘要

Significant dose reduction can be achieved in fluoroscopy and interventional radiology by using the last image holdrn(LIH). This feature in modern digital fluoroscopy x-ray units usually works with frame or temporal averagingrntechniques to reduce noise. This image quality works quite well for objects without motion but it could be a seriousrnlimitation in presence of motion blur. With an in-house developed robotic device, authors have experimentallyrndetermined the image quality degradation introduced by normal physiological movements (I.e., respiratory andrncardiac pulse movements). FAXIL test objects TO.10 and 18FG from Leeds University have been used for spatialrnresolution limit and threshold contrast detail detectability. Seven X-ray equipments with last image hold featuresrnfrom three different manufacturers were analysed. Although results show that motion blur affects LIH in differentrnextend depending on equipment, magnification, entrance dose and detail size, it can be estimated that, on average forrnall equipments and analysed conditions, represents 30% degradation in image quality parameters in comparison withrnstatic images.