Precise mapping system of entrance skin dose during endovascular embolization for cerebral aneurysm (Conference Paper)

摘要

Although several cases of radiation-induced skin injury (RSI) have been reported in association with neurointerventional procedures, such as endovascular embolization for cerebral aneurysm, the absorbed doses are not directly measured in most cases. We therefore built a direct measurement system in order to simplify determination of the entrance skin dose (ESD) during neurointerventional procedures. This system was then applied to patients undergoing long and repetitive procedures in order to establish the efficacy of precise mapping of ESDs using a number of radiophotoluminescence glass dosimeters (RPLDs) and to avoid RSI. We also analyzed the correlation between maximum ESDs and angiographic parameters in order to estimate maximum ESD in real-time. ESD was measured in 35 procedures in 34 cerebral aneurysm patients with a median age of 65 years (range, 38-79 years). Patients were measured for ESDs while wearing a fitted dosimetry cap equipped with 60 RPLD chips throughout the procedure. Angiographic parameters, including total fluoroscopic time and dose-area product (DAP), were recorded. The Pearson correlation test was used to determine the relationship between maximum ESD and each parameter. Five of thirty-five procedures showed temporal epilation (14.3%). The correlations between a patient's maximum ESD and total fluoroscopic time and DAP were r = 0.7372, P < 0.001 and r = 0.6698, P <.001, respectively. We concluded that the regional ESD with geometric information could be obtained by applying the RPLDs. Although this passive dosimetry system may not entirely prevent RSI in real-time, precise dose mapping accompanied by monitoring of angiographic parameters during the procedure should contribute to reducing X-ray dose accumulation in repeated prophylactic endovascular embolization for asymptomatic cerebral aneurysm.