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Bieu et al. Hepatoma Res 2020;6:49  I  http://dx.doi.org/10.20517/2394-5079.2020.39                                              Page 3 of 10

               Table 1. Patient characteristics pre-treatment and post-TACE and SBRT
                Lab test and imaging      Pre-treatment         Post-TACE 1 months     Post-SBRT 3 months
                AFP (IU/mL)                2479                   1128                    143
                PIVKA-II (mAU/mL)          272.6                  29.4                    0.8
                Child Pugh                 A5                     A5                      A5
                AST                        28                     43                      47
                ALT                        33                     65                      70
                Tumor size (mm)            71 × 60 × 53           72 × 63 × 43            60 × 43 × 38
               PIVKA: a protein induced by vitamin K absence; AST: aspartate transaminase; ALT: alanine transaminase; TACE: transarterial
               chemoembolization; SBRT: stereotactic body radiation therapy; AFP: alpha fetoprotein


               SBRT procedure for the patient
               CT simulation in GE CT 580 RT (USA)
               The patient lied supine, arm up, and was immobilized in a vacuum bag (Qfix - USA). A non-contrast 4D
               CT performed with 2.5 mm slice thickness (used for treatment planning). A contrast-enhanced 4D CT with
               2.5 mm slice thickness, intravenous injection of Omnipaque (GE Healthcare) 2 mL/kg, and 2.5 mL/second
               was performed (used for target volume contouring). Both 4D CT data sets were then transferred to the
               treatment planning system (TPS).

               Target volume and organs at risk contouring using Eclipse 13.6 (Varian, USA)
               The average CT images were created for both non-contrast and contrast-enhanced 4D CT data sets. Non-
               contrast average CT was co-registered and fused with the contrast-enhanced one. Then 10 gross tumor
               volumes (GTVs) were contoured in 10 contrast-enhanced 4D CT data sets: only delineated tumor with
               contrast enhancement. The 10 GTVs were copied to contrast-enhanced average CT data set and combined
               to create internal target volume (ITV). The ITV was propagated from contrast-enhanced average CT data
               set to the non-contrast one. The planning target volume (PTV) was created in non-contrast average CT
               from ITV: PTV = ITV + 5 mm. The organs at risk were contoured in non-contrast average CT including
               liver, lung, heart, stomach, duodenum, small and large bowel, spinal cord, chest wall, kidneys, and gall
               bladder.


               Dose prescription
               The prescription dose was 45 Gy in 3 fractions, based on normal tissue constraints (the report of AAPM
                             [17]
               Task Group 101 ).

               Treatment planning
               Treatment technique was VMAT with 2 coplanar arcs. Plan optimization was done in Eclipse 13.6 (Varian,
               USA). Based on normal tissue constraints, we selected a treatment plan with a total dose of 45 Gy in 3
               fractions for the patient [Figure 1].

               SBRT treatment plan parameters were shown in Table 2, with plan normalization 100% prescription dose
                                                                                            [16]
               covered 95% PTV and doses of OARs were within tolerance of AAPM Task Group 101 . Normal liver
               volume received less than 17 Gy (V17) was 812.7 mL.

               Quality assurance of treatment plan
               The treatment plan was verified by portal dose dosimetry (Varian, USA) with a 2%/1mm gamma passing
               rate of 99.5%.

               Treatment delivery
               The patient was treated in TrueBeam STx (Varian, USA) with position and immobilization just like in CT
               simulation. We used the Optical Surface Monitoring System (OSMS - Vision RT, UK) to help set up and
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