The aims of this study were to evaluate organ doses determined using Monte Carlo (MC) simulations for X-ray fluoroscopy and digital subtraction angiography in transcatheter arterial chemoembolization (TACE) procedure for hepatocellular carcinoma (HCC) and to validate the values through comparisons with the doses measured using in-phantom dosimetry.
METHOD AND MATERIALSFluoroscopy and angiography were performed with tube voltage of 70 and 80 kVp, added filtration of 0.5 mm copper and 1.8 mm aluminum, tube current of 47 and 160 mA, exposure time of 10.3 and 3.3 seconds, respectively. X-ray projection angles were posteroanterior (PA) for fluoroscopy, and PA and 30-degree right anterior oblique (RAO 30°) for angiography. The entrance skin doses (ESD) and organ doses were measured using 200 radio-photoluminescence glass dosimeters located at various organ positions on and within an adult anthropomorphic phantom. Dose-area products (DAPs) for fluoroscopy and angiography were also measured. For dose simulations, dose distribution images were obtained by inputting the geometry of a digital angiography system (Infinix; Toshiba Medical Systems, Japan), fluoroscopic and angiographic parameters and CT images of the phantom into MC simulation software (ImpactMC; CT Imaging, Germany). Organ doses for each organ were determined from dose values at the corresponding dose measurement positions on the dose distribution images.
RESULTSMeasured ESD and DAP were 8.1 mGy and 3.1 Gy cm2 for fluoroscopy, 71.2 mGy and 28.9 Gy cm2 for PA angiography and 68.4 mGy and 30.0 Gy cm2 for RAO 30° angiography. Relative differences between the simulated and measured doses were 5.1% for fluoroscopy, 4.3% for PA angiography and 1.7% for RAO 30° angiography. The relative differences were 9.2% to 11.3%, 5.1% to 11.0% and 8.9% to 14.0% for liver, stomach and colon within x-ray irradiated region in fluoroscopy, PA and RAO 30° angiography, respectively.
CONCLUSIONThis study showed that the simulated and measured organ doses agreed well. The doses determined using MC simulation will be useful for the evaluation of organ doses and the estimation of radiation risks for individual patients in TACE procedures for HCC.
CLINICAL RELEVANCE/APPLICATIONMC dose simulation will be useful for the real-time dose estimation for individual patients in fluoroscopy and angiography for interventional radiology.