Quantification of Radiotherapy CT image for Non-Small Cell Lung Cancer: Development of Longitudinal Registration Algorithm and Correlation Analysis of Lung Parenchyma Change and Planning Radiation Dose Distribution
Date Issued
2015
Date
2015
Author(s)
Chen, Po-Han
Abstract
Lung cancer is one of the leading cause of cancer deaths worldwide, including Taiwan, across gender. In Taiwan, the male mortality rate of lung cancer is as high as 48.9%. Surgery is the best and effective method in the early stage of the lung cancer. However, only 15% of the diagnosed patients are suitable for early-stage surgery. Surgery only is no longer considered for those being diagnosed at the middle to the late stage. Treatment for patients with middle-stage and late-stage may involve chemotherapy, radiotherapy, or a concurrent chemoradiation therapy. Radiation therapy, which is one of the primary therapeutic approaches for non-small cell lung cancer, is a treatment that uses high-energy rays or particles that destroy lung cancer cells. Radiation-induced lung damage (RILD) is a severe complication of radiotherapy in lung cancer patients that presents as a progressive pulmonary injury affecting prognosis and quality of life in patients. In this study a longitudinal registration algorithm is proposed for evaluating the lung parenchyma change after radiotherapy and the correlation to the given radiation strength and distribution of dosage. The proposed registration algorithm overcomes the large parenchyma change which makes the registration much harder by using anatomical structures around the lung, including using spine for the reference set of rigid registration step; using three anatomical structures: bone structures surface, including sternal, rib and spine, airway wall and surface of lower lung to describe the longitudinal difference of breath holding degree. Reference points are sampled from these three anatomical feature structures for the further step of coherent point set registration. Registered by the proposed longitudinal registration algorithm developed by this study, the correlation of regional dose distribution with longitudinal parenchyma change has been evaluated and obvious parenchyma change in the region of radiation dosage above 22 Gy and in 3~7 month is observed.
Subjects
parenchyma change induced by radiotherapy
bone segmentation
lower lung surface segmentation
feature point sampling
longitudinal registration
SDGs
Type
thesis