Factors affecting target motion in stereotactic body radiotherapy of liver cancer using CyberKnife.

Introduction: In stereotactic body radiation therapy (SBRT) of solitary liver cancer, organ motion due to respiration is an important factor in the definition of planning target volume (PTV). This study evaluated the potential associations of target motion with gross tumour volume (GTV) size, tumour location, Child-Pugh score and intra-fraction treatment time in SBRT of liver cancer treated by CyberKnife.

Methods: Translational motion data of 145 liver cancer patients, who were previously treated by CyberKnife with free breathing under tumour tracking, were recorded in the log files of the motion tracking system and analysed.