Feasibility and Efficacy of Single Photon Emission Computed Tomography-Based Three-Dimensional Conformal Radiotherapy for Hepatocellular Carcinoma 8 cm or More With Portal Vein Tumor Thrombus in Combination With Transcatheter Arterial Chemoembolization

Cutoff Values for Dose-liver Function Parameters to Prevent Radiation-induced Liver Disease in Advanced Hepatoma

“…These low-dose beams were designed to avoid irradiating organs at risk, such as the stomach, duodenum, and spinal cord. Doses of 3.5 Gy for each additional beam did not cause liver damage, even if the beams irradiated the FLV [9,10] . In terms of the kidney, the volume irradiated with 20 Gy or more was planned to be ≤30% of the total volume.…”

“…FL does not always correspond to the normal liver in patients with liver cirrhosis and/or HCC with PVTT [23] . GSA-SPECT usually shows no accumulation of radioactivity in the normal liver in the lobe with the tumor thrombus, so the normal liver is registered as dysfunctional liver [9,10] . We attempted to plan the radiation regimen to irradiate the HCC plus the PVTT and the dysfunctional liver to avoid irradiation of the FL area [9,10] .…”

“…The optimal 3DCRT beam directions (optimal angles of the gantry) were explored using the SPECT images for guidance, as proposed by Shirai et al [9,10] . The directions of the two high-dose beams were Exactness of ≤5 mm of stop-breathing at end-expiration designed to primarily cover the main tumor and PVTT, and to irradiate the FLV as little as possible [9,10] .…”

“…The directions of the two high-dose beams were Exactness of ≤5 mm of stop-breathing at end-expiration designed to primarily cover the main tumor and PVTT, and to irradiate the FLV as little as possible [9,10] . As shown in Figure 1-D, the doses of the high-dose beams were limited to 38 Gy/18 fractions/four weeks to prevent adverse effects to the duodenum, spinal cord, and kidneys [15,16] .…”

“…Therefore, in this study, we attempted to create a cutoff value to predict RILD more exactly than FLV20Gy using Tc-99m GSA counts as the liver function digital data [6] . The purpose of this study was to retrospectively determine the cutoff values for predicting RILD in HCC patients with portal vein tumor thrombus (PVTT) at the main trunk and/or the first branch, associated with Child A or B liver cirrhosis, who had previously received SPECT-based three-dimensional conformal radiotherapy (SPECT-B-3DCRT) [9,10] , using the digital counts of Tc-99m GSA.…”