2009 Fiscal Year Final Research Report

Target volume determination with four-dimensional CT in radiotherapy for lung cancer

Research Project

Project/Area Number	20790900
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Radiation science
Research Institution	Kumamoto University
Principal Investigator	SAITO Tetsuo Kumamoto University, 医学部・附属病院, 医員 (30467980)
Project Period (FY)	2008 – 2009
Keywords	肺癌 / 呼吸同期照射 / 4D-CT
Research Abstract	At phase-based gating, the dosimetric parameters and treatment times are similar, irrespective of whether gating is around end-expiration or end-inspiration. At amplitude-based gating, a greater reduction in the lung dose is obtained when gating is around end-inspiration rather than end-expiration, however, the treatment time is prolonged considerably. When a 30% duty cycle is used, significant reduction in lung dose is achieved at the expense of modest prolongation of treatment time using phase-based gating around end-expiration. Three dimensional tumor motion, craniocaudal tumor motion, and the craniocaudal tumor position are useful for predicting the benefit of respiratory-gated radiotherapy in lung cancer patients. Tumor volume is not a useful factor.