Robustness analysis of sparsity based tumor localization under tissue configuration uncertainty

Knowing the exact position of the tumor is a very critical prerequisite in radiation therapy. Since the position of the tumor changes because of respiration or patient movements, a real-time tumor tracking method must be applied during the process of radiation therapy in order to deliver a sufficient dose of radiation to the tumor region without damaging the surrounding healthy tissues. In this paper, we develop a novel tumor positioning method based on spatial sparsity and then we investigate the sensitivity of this method to the uncertainty of tissue configuration. The proposed method is easier to implement, non-iterative, faster and more accurate compared to common magnetic transponder based approaches. The performance of the proposed method is evaluated in two different cases: (1) when the tissue configuration is perfectly determined (acquired beforehand by MRI or CT) and (2) when there are some uncertainties about the tissue boundaries. The results demonstrate the satisfactory accuracy and high performance of the proposed method, even when the tissue boundaries are imperfectly known.