ABSTRACT
CONTENTS 7.1 Introduction 100 7.2 PCA-Based Lung Model 101 7.3Optimization Model for Real-Time CBCT 103
7.3.1Formulation of the Real-Time CBCT Problem 103 7.3.2Optimization Using an Ecient Alternating Algorithm 103 7.3.3Tumor Localization via Deformation Inversion Based
on an Ecient Fixed-Point Algorithm104 7.3.4Fast Computation through Algorithm Implementation
on GPU105 7.4Experimental Results 105
7.4.1Evaluations Using Digital and Physical Respiratory Phantoms 105
7.4.2Evaluations Using Real Patient Data Sets 107 7.5Conclusion and Discussions 109 References 110
Respiratory-induced tumor motion is a major issue in radiother-apy 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]. is 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. erefore, it is important to reduce the breathing motion-induced safety margin. is is crucial for stereotactic body radiation therapy (SBRT), which is ablative not only to the tumor, but to normal tissues as well [3,4].
