2000 Fiscal Year Final Research Report Summary
Automatic optimazation in non-coplanar three-dimensional radiotherapy
| Project/Area Number |
10670828
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | University of Tokyo |
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Principal Investigator |
AOKI Yukimasa University of Tokyo, Radiology, Associate Professor, 医学部・附属病院, 助教授 (40143474)
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| Co-Investigator(Kenkyū-buntansha) |
TERAHARA Atsuro University of Tokyo, Radiology, Assistant Professor, 医学部・附属病院, 講師 (80237007)
ONOGI Yuzo University of Tokyo, Medical Information, Associate Professor, 医学部・附属病院, 助教授 (90233593)
NAKAGAWA Keiichi University of Tokyo, Radiology, Assistant Professor, 医学部・附属病院, 講師 (80188896)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Non-coplanar radiation / 3-D treatment planning / Automatic optimization / Dose distribution / Inverse algorithm / IMRT |
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| Research Abstract |
The authors compared dose distributions with non-coplanar three-dimensional radiotherapy and conventional rotational CRT.DVH analyses were performed on dose homogeneity within the target and dose inhomogeneity of the critical organs. Automatic optimization algorithm in non-coplanar three-dimensional radiotherapy was completed and applied for actual patients. Adverse effects in normal structures were reduced with this method. Fundamental study on radiation treatment planning systems using a volume graphics board proved to reduce the time for the 3-D visualization of the dose distributions in non-coplanar three-dimensional radiotherapy. Dynamic conical conformal therapy using a c-arm accelerator was developed and showed superiority in dose distribution. We have modified the inverse planning and developed a new high-performance calculation method, confirming its validity in a case of head and neck tumor. The treatment parameters are defined as the intensity modulated beam weight distribution for all portal beams. A multiple-step gradient method is used to optimize dose distribution. We have confirmed the availability of this method by applying it to a case of oropharynx carcinoma, in which we used fixed five ports on 2D image. The DVH analysis revealed that OAR exposure can be reduced if we allow increased dose non-uniformity in PTV.The advantages of the proposed multiple-step gradient method with prescription tuning capability are fast calculation and reduced risk for local minimum problems.
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