The Feasibility Analysis of Predicting Tumor Position in vivo by Respiratory Motion Track of Body Surface Markers in Radiotherapy
| Autor: | CHEN,KE-WEI, 陳科維 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 According to the data of Ministry of Health and Welfare announced in 2017, malignant tumor has been the main cause of death for 36 consecutive years in Taiwan. The most common treatment for malignant tumors is radiation therapy, but during the course the tumor moves with the patient's respiratory motion, which may make the therapy less effective. How to reduce the uncertainty of the respiratory movement of a tumor has been an important issue in radiation therapy. A commonly used method in the clinic is to use a positioning marker placed on the body surface to track the respiratory state, and repeat the irradiation to the tumor at the same state to reduce the uncertainty caused by the breathing. In this study, we experimentally investigated whether an in vitro fiducial marker on the body surface (BSFM) could be used to predict the trajectory of an in vivo tumor with respiratory motions. We use an infrared camera and a visible camera to record the three-dimensional coordinates of the externally-reflected infrared-reflecting points moving in the image space with the breathing, and locate both BSFM and tumor from 10 sets of 4DCT images with different breathing depths. The corresponding mapping between the coordinates obtained from the optical images and the 4DCT images can be divided into two parts. The first part is the mapping from optical images to 4DCT images of the BSFM locations. The second part is the mapping from BSFM locations to tumor locations in the 4DCT images. Two parts of mapping changing with the time are approximated by polynomial fitting. Eventually the coordinates of tumor in 4D-CT can be estimated from the coordinates of BSFM in the image space of cameras. When patients receive radiotherapy, such technique allows us to directly infer the position and motion of an in vivo tumor from its BSFM captured by the outside video cameras. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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