The aim of this paper is to study the feasibility for determining the individual internal target volume (ITV) for hepatocellular carcinoma (HCC) using 3DCT associated with active breathing coordinator (ABC), comparing the ITVs defined by 3DCT associated with ABC and 4DCT. Thirteen patients with HCC after transarterial chemoembolization (TACE) treatment underwent 4DCT simulation and 3DCT simulation associated with ABC in free breathing (FB), end inspiration hold (EIH) and end expiration hold (EEH). The 4DCT images were sorted into 10 phases according to the respiratory cycle and labeled as CT₀, CT₁₀...CT₉₀; and CT_MIP (the maximum intensity projection image) was reconstructed. GTV₀, GTV₁₀…GTV₉₀, GTV_MIP on 4DCT, and the GTV_FB, GTV_EIH, GTV_EEH on 3DCT were contoured. GTV_0,10…90, GTV₀ and GTV₅₀, GTV_EIH and GTV_EEH were merged into ITV₁, ITV₂ and ITV₃. The individual margins from GTV_FB to ITV_1-3 were obtained and applied to ITV_FB (labeled as ITV_FB-1, ITV_FB-2, ITV_FB-3), respectively. All the target volumes were normalized by ITV₁. The volume of GTVs, ITVs and the margins were compared. There was no significant difference of diaphragm mobility between 4DCT and 3DCT (P > 0.05), nor significant difference among the volume of the GTVs. The three ITVs were larger than the GTV_MIP (P < 0.05), but there was no significant difference among three ITVs. It’s similar to the differences both in the margins of three dimensions from GTV_FB to ITV_1-3 and in the volumes among ITV_FB-1, ITV_FB-2 and ITV_FB-3 (P > 0.05). This study shows that it’s safe and feasible to determine the individual ITV for HCC using 3DCT associated with ABC in comparison with 4DCT.

Key words: Hepatocellular carcinoma; Three/Four-dimensional computed tomography; Active breathing coordinator; Internal target volume.

This article can be cited as:
Guanzhong Gong, M.D., Yong Yin, Ph.D., Ligang Xing, Ph.D., Yujie Guo, M.D., Jinhu Chen, M.D., Tonghai Liu, M.D., Jie Lu, M.D., Changsheng Ma, M.D., Tao Sun, M.D., Tong Bai, M.D., Guifang Zhang, M.D., Wei Deng, M.D., Comparison of Internal Target Volumes for Hepatocellular Carcinoma Defined Using 3DCT with Active Breathing Coordinator and 4DCTTechnol Cancer Res Treat. 10, 601-606 (2011).