The Basic And Clinical Research On Stereotactic Radiotherapy For Lung Cancer

Stereotactic radiotherapy for lung cancer demands the strict localization of the target volume. But tumor motion does exist due to breathing. Reports on measurement of tumor motion are different at present. The patients are under thesame condition __breathing quietly both in the process of the positioning thetarget volume using computer tomography before the stereotactic radiotherapy and receiving the treatment. There are no reports at present on the keeping what kind of the relationship between scanning time and respiratory cycle to prevent losing the scanning information. At present the reports on the methods of adding margins on gross tumor volume (GTV) to compensate the impact on positioning due to respiratory motion are actually adding the margins on the target that already includes the effect of moving factor. How to determine the planning target volume (PTV) in reason to assure the complete radiation on tumor without increasing normal tissue complication probability (NTCP)? To answer these questions we performed these experiments.I. Measurement of the moving extent of lung tumor and diaphragm and the moving effect oh the changing of the results of the largest diameter of the lung tumor.We performed the measurement of the moving extent of lung tumor and the largest diameter of the tumor on direction of X, Y and Z-axis, the measurement of the diaphragm on direction of Z-axis, and compared the moving effect on the results of the largest diameter with the largest diameter of the tumor of 49 lung cancer patients receiving stereotactic radiotherapy. There are no detailed...