Research progress on target delineation for radiotherapy in hepatocellular carcinoma with

Modern medical imaging techniques, such as computed tomorgraphy (CT), magnetic resonance imaging (MRI) and position emission tomorgraphy/computed tomorgraphy (PET-CT) can accurately delineate the gross target volume (GTV) of hepatocellular carcinoma (HCC). Comparison of postoperative pathological subclinical lesions, imaging and clinical parameters contributes to the precise delineation of clinical target volume (CTV). Moreover, radiotherapy-assisted techniques, such as four-dimensional computed tomography (4DCT), compression of abdomen, active breathing control and respiratory gating, can minimize the internal target volume (ITV). In addition, immobilization with vacuum cushion and body membrane can reduce the set-up error, minimize the planning target volume (PTV) and avoid or decrease the irradiation error or missing irradiation. All these approach can minimize the target volume, elevate the dose and reduce the complications during radiotherapy for HCC. In this article, the research progress on the target delineation for external beam radiotherapy in HCC patients was reviewed. Key words: Hepatocellular neoplasm/radiotherapy; Target delineation; Progress