Eye lens dose measurement in patients during brain arteriovenous malformation interventional neuro-radiology procedure

Brain arteriovenous malformation (AVM) interventional neuroradiology (INR) is a complicated procedure which the patients may receive the high radiation dose exceeding the threshold level for detectable eye lens opacities and cataracts (ICRP, 2012). The objectives of this study are to measure the patient eye lens dose using optically stimulated luminescence dosimeter, OSLD, during AVM INR procedure at Interventional Radiology Unit, Department of Radiology, King Chulalongkorn Memorial Hospital (KCMH) and to study the factors affecting the patient eye lens dose. NanoDot OSLDs were attached on the transparent radiation thin film eyewear and closed to the patient eyelids during the procedure. Philips Allura Clarity Xper FD20/15 biplane system has been used and parameters related to acquisition protocol were recorded. The size and site of brain AVM lesion and experience of interventional neuroradiologists were included. 32 AVM INR patients include 15 therapeutic and 17 diagnostic procedures were studied from August to December 2018. The results show that: therapeutic procedure, the average and range of patient left and right eye lens doses were 65.14 (17.88 – 111.70) and 29.62 (11.63 – 56.81) mGy, KAP at PA and lateral X-ray tubes were 112.05 (41.62 – 305.44) and 57.42 (19.73 – 102.99) Gycm2, AK at PA and lateral tubes were 1.80 (0.50 – 5.17) and 1.26 (0.38 – 2.98) Gy, and the exposure time was 77.15 (26.52 – 186.56) minutes. The average left eye lens dose was higher than the right eye. KAP, AK and total exposure time were correlated to patient eye lens dose by r = 0.60, 0.58, 0.44. The beam collimation, frame rate, angular and rotation of X-ray tube, the experience of specialist and complexity index of the procedure influence the patient eye lens dose. The average patient eye lens dose in a single procedure was less than 0.5 Gy, the threshold dose level of eye lens opacities and cataracts. The collimated irradiation area, reduce frame rate, speed and the short distance from flat panel detector to patient have been commonly selected, especially in patients with multiple procedures.