The main indication for IMRT included liver tumors with macrovascular invasion; distant metastasis treated with palliative IMRT. For patients with bilobar multiple HCCs, as many lesions as possible were chosen for IMRT without exceeding the tolerance limits of the organs at risk. All patients underwent enhanced computed tomography (CT) scan at 2.5–5 mm slice thickness for IMRT planning. CT-positron emission tomography fusion and magnetic resonance imaging fusion were performed for identifying extrahepatic metastasis and intrahepatic lesions, respectively. Gross tumor volume (GTV) was defined as the tumor focus. The GTV and at-risk organs were contoured using the Pinnacle 3 system (Philips, Netherlands) or the MIM software (version 6.8; MIM, USA). The planned target volume (PTV) was defined as the GTV plus an asymmetrical dilation of 1 cm in the craniocaudal direction and 5 mm in the axial direction to set the uncertainty and respiratory movement. The IMRT plans were designed using Pinnacle 3 or the Monaco treatment planning system version 5.1. The final median biologically effective dose, which used α/β ratio = 10 according to the linear-quadratic model, was 51 Gy (interquartile range, 40–51 Gy). IMRT was delivered via a 6 MV X-ray linear accelerator (ELEKTA Synergy or ELEKTA Versa-HD, Sweden) using cone-beam CT to correct the positions.18 (link)