重粒子泛指包含質子、碳核、π介子等重帶電粒子，而重粒子治療是利用重帶電粒子進行放射線治療，最早的理論在1946年由WILSON的論文中發表，其理論爲利用質子所產生的布拉格峰(Bragg peak)曲線，將其置於腫瘤（靶區）以達到殺死腫瘤細胞並降低正常組織所受劑量之目標。1954年Tobias與其團隊於美國加州大學勞倫斯貝克實驗室(Lawrence Berkeley laboratory. LBL)進行世界第一例質子治療，1991年美國Loma Linda大學附屬醫學中心爲世界第一個啟用醫用質子裝置之醫學中心。1993年日本千葉放射線醫學總合研究所(National Institute of Radiological Sciences. NIRS)所開發的千葉重離子醫用加速器(Heavy Ion Medical Accelerator in Chiba. HIMAC)設置完成，自1994年6月至2006年2月共治療2629人。重粒子治療以往礙於粒子加速不易導致其加速器體積過於龐大，昂貴等理由而使其普及不易，而日本千葉放射線醫學總合研究所於2006年完成較以往約小1/3至2/3的加速裝置，其發表內容表示新的加速裝置可以大幅將低設置所需的場地及費用。而本文將對日本千葉放射線醫學總合研究所建立的千葉重離子醫用加速器其相關研究內容作一簡介。

This study is aimed for the valuable improvements of medical accelerator at National Institute of Radiological Sciences Japan and reveals researches and practical usages of heavy ion particle. Charged heavy ion particle radiotherapy has been using heavy ion particle to treatment tumor or lesion. Heavy ion particle includes proton, carbon nuclear, n .etc. The early theory of heavy ion particle was proposed by Robert. W. Wilson in 1946; he suggested that proton Bragg peak for tumor or lesion may kill tumor and decrease normal tissue dose. Soon after that, in 1954, Tobias and his team were successfully experimented the world first proton therapy of a human organ in Lawrence Berkeley Laboratory in University of California. Later, in Loma Linda University Medical Center, some scientists built up the first medical proton treatment equipment in 1991. Two years after that in National Institute of Radiological Sciences of Japan, they developed heavy ion medical accelerator in Chiba; 2629 patients were treated from June 1994 to February 2006. However, heavy ion particle can not be accelerated easily due to its weight. Therefore, the accelerator was built in high cost and its usually in huge shape. Lately, in 2006, National Institute of Radiological Sciences of Japan has succeeded in improving the accelerated equipment. The volume was 1/3 smaller than the previous model and the building cost has decreased substantially.