Abstract

EUFRASIO, Sérgio et al. The risk of exposure to ionizing radiation during endovascular procedures. Angiol Cir Vasc [online]. 2013, vol.9, n.3, pp.84-89. ISSN 1646-706X.

Objectives: The resource to endovascular procedures has become progressively more frequent and has increased concerns regarding the deleterious effects from radiation exposure. The purpose of this investigation is to evaluate and quantify scattered radiation exposure to which the patient and the surgical team are exposed, produced by a portable C-arm radioscopy unit during its use in the operating theatre. Material and methods: Radiation dose was measured in a controlled operating room with reproduction of usual conditions experienced during endovascular procedures in our operating theatre. A 15 cm polimetilmetacrilate phantom was used as a geometrical simulation of the thorax. The scattered radiation was measured in several positions which were determined according to the usual distribution of the surgical and anesthesiological team in the room and at several heights. Radiation quantification was accomplished with resource to a portable radiation monitor RaySafe Xi Survey Detector, adjusting dose rate in mGy/s. Additionally, a RaySafe Xi R/F detector was used to measure the skin entrance exposure of the simulated patient. Readings were taken in pulsed fluoroscopy mode at a frequency of 4 frames per second (fps), digital subtraction mode and roadmap mode. The different magnifications available (Mag 1, 2 and 3) were also combined with each of these modes. In all situations, x-ray unit radiation dose was setted on level 3 which usually provides the best quality images with automatic real-time control of contrast and brightness. Results: Data analysis determined the distribution of scattered radiation among all elements of the surgical team. Maximum level of exposures was found at a height of 120 cm in digital subtraction and roadmap modes. In this setting, surgical team scattered radiation exposure rates relative to patient skin entrance exposure rates were 0.47% for the surgeon, 0.21% for the anesthesiologist, 0.32% for the first assistant and 0.13% for the instrumenting nurse. The use of digital subtraction and roadmap increased levels of radiation exposure to patient and surgical team 5 times in comparison to pulsed fluoroscopy mode at 4 fps. When personal radiation protection shielding was used, radiation levels were considerably inferior. Conclusions: Proximity to the radiation x-ray tube increases significantly the amount of scattered radiation received. With the use of personal radiation shielding, the exposure is considerably lower and recommended radiation dose limits are not exceeded.

Keywords : Occupational radiation exposure; Dosimetry; Endovascular procedures; Radiation protection.

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