放射線為癌症治療中常見且相當重要的一種醫療方式，目前放射線治療新發展的技術為強度調控放射線治療(Intensity Modulated Radiation Therapy, IMRT)，其調節放射劑量分佈，將高劑量集中於腫瘤，並減少正常組織之傷害。儘管目前放射線醫療的技術與設備已相當完善，但於放射治療計劃中，射束角度的選擇仍取決於醫學物理師的經驗或是直覺。
本篇論文的研究為在考量整體放射線射束角度下，針對射束結構進行最佳化的選擇。除了腫瘤及周遭組織必須滿足劑量限制外，劑量分佈也將納入考量，同時最佳化放射線射束角度結構及射束強度大小，並利用幾何空間角度的限制加快求解速度，以使射束角度選擇之規劃更貼近放射線醫療並符合實際需求。最後，與目前放射線醫療角度之規劃進行比較，本研究將提供較佳的角度決策，以做為醫學物理師角度規劃之參考。

Radiation therapy is a common and important treatment for some specific tumors in the treatment of cancer. At present, a new development of radiation therapy is being generated, namely, the intensity modulated radiation therapy (IMRT). IMRT modulate the intensity of the radiation beam to focus on a higher radiation dose to the tumor while minimizing radiation exposure to surrounding normal tissues. The technology and equipment of radiation therapy have already been quite developed at present. However, selecting appropriate beam orientations is manually completed by a planner according to his (her) experience and intuition in current clinical practice.
The purpose of this thesis is the optimal selection of the beam configuration by considering the beam orientation completely. Besides the radiation dose limit to the tumor and the adjacent organs needed to be satisfied, we take the dose distribution into consideration and optimize the beam configuration and beam intensity simultaneously. In addition, we accelerate the speed of optimization by the limits of the geometric spacing to make the treatment plan of selecting beam orientations meet radiation therapy in clinical. Furthermore, the proposed model compared with the equi-spaced model provides the optimal beam configuration to help physicists in decision-making.

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