A STUDY OF 3-D MR SIMULATION SYSTEM FOR RADIOTHERAPY PLANNING

Research Project

Project/Area Number	05670778
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Radiation science
Research Institution	KOBE UNIVERSITY
Principal Investigator	SAKAGUCHI Toshiya (1994) Kobe University School of Medicine, Department of Radiology, assistant professor, 医学部, 助手 (90205732) 今中一文 (1993) 神戸大学, 医学部・附属病院, 講師 (30211064)
Co-Investigator(Kenkyū-buntansha)	KODAMA Akihisa Kobe University School of Medicine, Department of Radiology, assistant professor, 医学部, 助手 (30252787) ITOUZI Eiitirou Kobe University School of Medicine, Department of Radiology, lecturer, 医学部・附属病院, 講師 (90243302) YAMAZAKI Katuhito Kobe University School of Medicine, Department of Radiology, lecturer, 医学部・附属病院, 講師 (50210381) KONO Michio Kobe University School of Medicine, Department of Radiology, professor, 医学部, 教授 (60030938) 坂口俊也神戸大学, 医学部, 助手 (90205732) 足立秀治神戸大学, 医学部, 講師 (60159407)
Project Period (FY)	1993 – 1994
Project Status	Completed (Fiscal Year 1994)
Budget Amount *help	¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1994: ¥300,000 (Direct Cost: ¥300,000) Fiscal Year 1993: ¥1,200,000 (Direct Cost: ¥1,200,000)
Keywords	radiation therapy / treatment planning / CT simulation system / MRI / MR simulation system / 放射線治療計画 / MR simulation system / 頭頸部腫瘍 / CT simulation system
Research Abstract	The purpose of this study is to investigate the accuracy of MR simulation system (MRSS). MRSS consists of a MR unit (Phillips Gyroscan S15) , a work station (NEC pc9821 AP2/M2, PC HD/70F) , and a laser marking system (YMS RT/MARKER) in CT simulation system. A) Procedure of MRSS : 1) Target was set in the phantom and the center of the magnetic field (CMF) was marked on the phantom using 3 pointers which were installed to obtain accurate information of the position. 2) MR scan was performed with sequential 5 mm axial slice. 3) Each MRI was transferred to new work station through floppy disk to determine the target and to calculate the contour of radiation field and the coordinate of iso-center. 4) Phantom was moved to the CT table to correspond CMF with a standard point of simulation system 5) The calculated iso-center position was reproduced and projected on the target by laser marking system. B) Experimental study : 1) The degree of distortion of MRI was examined using checkered phantom. 2) The calculated field size was compared with practical target size, and the deference between reproduced iso-center and practical iso-center was surveyed. C) Clinical study : We performed MRSS to 5 patients. They were seemed to be some difficulty in using CTSS.Their target margin were not clear on CT because of artifact or previous radiation. C) Conclusions : 1) The distortion of MRI was less than 1 mm within 1 mm from the center of the magnetic field. 2) The difference in the position of the iso-center was 0.3 mm, 0.6 mm, 0.8 mm, in X,Y,Z axis. The maximal difference in the size of radiation field was 2mm. 3) On the clincal use, MRSS was useful on the cases which target were not clear on CT.