Tumor tracking and real-time volumetric imaging via one cone-beam CT projection

RESPIRATORY-INDUCED TUMOR MOTION IS a major issue in radiotherapy and requires careful management [1]. To account for the uncertainty caused by breathing motion, the conventional approach is to expand the target volume by adding a safety margin around the tumor [2]. This inevitably leads to a large volume of normal tissues being irradiated and increased toxicity, which is the main limiting factor for dose escalation and potential gain in local control. Therefore, it is important to reduce the breathing motion-induced safety margin. This is crucial for stereotactic body radiation therapy (SBRT), which is ablative not only to the tumor, but to normal tissues as well [3,4].