質子治療機質子治療物理特性的分析及比較

The Introduction and Analysis of the Physics Aspect of Proton Treatment

吳嘉明(Jia-Ming Wu) ； 葉世安(Shyh-An Yeh) ； 蕭光吟(Kuan-Yin Hsiao) ； 陳宗哲(Tzong-Jer Chen) ； 趙敏(Max M. Chao)

《台灣應用輻射與同位素雜誌》 5卷2期 (2009/06) Pp. 645-652

https://doi.org/10.29832/TJARI.200906.0002

摘要

把質子運用於放射治療的想法始於1946年，但由於加速質子比產生高能光子需更昂貴的機件配件及射束傳輸系統，所以質子爲癌症治療的主要機器的做法在這之前並不普及；但隨著放射治療臨床醫師及醫學物理師，輻射生物學家對質子所提供高劑量且劑量集中於布雷格尖峰的百分深度劑量明顯優於高能光子的特性後，現今最熱門的課題均圍繞在質子治療機或小型質子治療機上；近年來有逐漸形成一股氣候的趨勢，所以本文參考國內外的文獻，深入探討質子的物理特性及針對質子運用在臨床治療上所需要量測的資料爲主軸，介紹其物理和臨床劑量特性，以期勉各先進不令吝指教，且後起之秀能起而學之，讓質子的運用更穩定、更成熟；讓癌症患者得到更精準的治療及讓病人在治療過程中輻射對正常組織或器管的傷害減到最低。

關鍵字

質子治療 ； 物理特性 ； 布雷格尖峰

並列摘要

The number of centres investigating proton therapy in the hvorld is steadily increasing. This review on the present status of proton therapy is addressed to physicists not working in the field. The presentation includes a brief summary of the established medical indications and of the state of the art of the application techniques used. The future trends are seen in the new technological developments, like the use of proton gantries, beam scanning techniques, improved patient handling and in the increasing precision of treatment. The availability of modem diagnostics tools like CT and MRI, accompanied by an extremely fast growth of computer power are expected to help charged particle therapy to become more and more attractive in the future. The main purpose of proton therapy is the use of proton beams for the treatment of localised tumours and for radiosurgery with the goal to improve radiation therapy. The expected improvements are of purely technological nature and are represented by the capability of the protons to produce superior dose distributions in the patient’s body compared to photons. As opposed to heavier ions, which by their enhanced high LET (linear energy transfer) produce remarkable differences in the radiation effects at the cellular level, we do not expect with protons any significant radiobiological differences compared to photon treatments. Protons have the potential to bring significant improvements to radiation therapy by virtue of their excellent physical properties. The dose delivered by a proton beam is well localised in space, not only in the lateral direction, but also very precisely in depth, due to the presence of the characteristic Bragg peak The presence of the Bragg peak has to be compared with the corresponding dose curve for photons, which exhibits an exponential fall-off and which is therefore not localised in depth.

並列關鍵字

proton ； physics ； Braggy peak