Monaco treatment planning system version 5.1

All patients underwent enhanced CT scan at 2.5-5 mm slice thickness for IMRT planning. Patients were immobilized by vacuum molds or thermoplastic body films in the supine position with free quiet breathing mode. Gross tumor volume (GTV) was identified as tumor focus. The GTV and organs at risk were contours in the Pinnacle 3 system (Philips, Netherlands) or MIM 6.8 system (MIM, USA). Whenever conditions permitted, CT-positron emission tomography (PET-CT) fusion for the extrahepatic sites and CT-magnetic resonance imaging (MRI) fusion for intrahepatic lesions were performed. For patients with multiple lesions, 1–5 lesions were selected for IMRT at the discretion of the radiation oncologists. IMRT plans were designed using the Monaco treatment planning system (version 5.1) or Pinnacle 3 system (Philips, Netherlands). The final median biologically effective dose used α/β ratio = 10 was 67.2 Gy (IQR, 60–78 Gy). The RT was received using a 6 MV X-ray linear accelerator daily over five fractions per week.

The contrast-enhanced computed tomography (CT) scans for the dose calculation plans were underwent by positioning the patients in supine with their arms overhead during free quiet breathing. Gross tumour volume (GTV) including macrovascular invasion (MVI) was clearly delineated using the contrast-enhanced CT and CT–magnetic resonance imaging fusion. The GTV was expanded to 4–5 mm to establish the clinical target volume (CTV). The planning target volume included the CTV plus a 5–10 mm margin, implemented to account for respiratory motion and setup uncertainty. All target areas and organs at risk were contoured using the Pinnacle 3 system (Philips, Netherlands) or MIM 6.8 system (MIM, USA). IMRT plans were designed using the Monaco treatment planning system (version 5.1) or the Pinnacle 3 system (Philips, Netherlands). Among the 75 patients, the median total GTV dose was 53.24 Gy ± 7.26 Gy (mean ± standard deviation), with a median of 2.96 Gy ± 0.84 Gy per fraction; each fraction was 3 to 5 days a week. IMRT was administered to all patients using a linear accelerator with 6 MV X-rays (ELEKTA Versa-HD or ELEKTA Synergy, Sweden).