Development of robust four-dimensional intensity modulated radiotherapy

2015 Fiscal Year Final Research Report

• Project/Area Number: 26713022
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Medical Physics and Radiological Technology
• Research Institution: National Cancer Center Japan
• Principal Investigator: Tachibana Hidenobu 国立研究開発法人国立がん研究センター, 先端医療開発センター, 医学物理専門職 (20450215)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 追尾照射 / 四次元CT / DIR / CT pulmonary ventilation / Quality assurance

Outline of Final Research Achievements

To investigate a weighted four-dimensional (W-4D) treatment planning strategy based on the greater clinical advantage of the conformal over the intensity-modulated technique in lung stereotactic body radiotherapy (SBRT). W-4D was evaluated in eighteen lung SBRT patients.The W-4D plan’s key concept was to escalate (or reduce) fluence using a 4D optimization algorithm when the tumour target was out-of-line (or in-line) with an organ-at-risk. The fluence was converted to a dynamic multi-leaf collimator leaf sequence for deliverable 4D irradiation. In all patients, the W-4D plan enabled planning tumour volume conformity comparable to the conventional 4D plan. The W-4D is a robust, practical planning approach that achieves significant dose sparing relative to non-time-resolved tracking; it may be of greater clinical benefit in radiotherapy than the spatially intensity-modulated 4D approach.

Free Research Field

放射線治療医学物理