1997 Fiscal Year Final Research Report Summary

Development of system of irradiation synchronized with respiration gate

Research Project

Project/Area Number	08671044
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Radiation science
Research Institution	SAPPORO MEDICAL UNIVERSITY
Principal Investigator	MORITA Kazuo Sapporo medical university, Department of Radiology, Professor, 医学部, 教授 (20045347)
Co-Investigator(Kenkyū-buntansha)	SAKATA Koh-ichi Sapporo medical university, Department of Radiology, Assistant professor, 医学部, 講師 (10235153) HAREYAMA Masato Sapporo medical university, Department of Radiology, Associate professor, 医学部, 助教授 (10173098)
Project Period (FY)	1996 – 1997
Keywords	Respiratory movement / Lung tumor / Treatment planning
Research Abstract	We examined how we can decide the appropriate irradiation field and radiation technique to the target moved by respiration. When we consider the radiation technique to the tumor of the lung apex, the target volume is usually decided by using CT imagings that are taken when breath is stopped. However, because the tumor of the lung apex moves from anterior oblique to posterior oblique at the respiration, the radiation dose of some part of the target can decrease. Then, we took CT imagings at inhalation and expiration before the treatment planning. The tumor volumes at inhalation and expiration were summed and the treatment planning was performed by using the summed target volume. By this treatment planning, we can decide the direction of the beam to prevent the target deviate from the irradiation field. To realize this, it is required to have the function to synthesize the two target volumes. We could solve that problem by inputting the two target volumes. We could solve that problem by … More inputting the two target volumes to the three-dimensional treatment planning system. Because this makes the movement of the target in the three-dimensional space make clear, we can irradiate the target through the optimal direction. In the usual way, after the treatment planning, we verify the movement of the target with the x-ray simulator and enlarge the radiation field. As compared with the usual way, this new method could decrease the treatment volume more. When the target moves with the physiological movement of the organ, there was the uncertainty at the decision of the target volume in the usual way of the treatment planning in which CT imagings at one moment of the moving target are used. Then, we developed the method of three-dimensional treatment planning by using two mamaximum values of the moving target. By using this method, we can solve the uncertainty in the usual way of the treatment planning, know the minimum treatment volume, minimize the danger that the target volume deviates from the radition field, and make the optimum treatment planning to the moving target. Less