質子自1919年被物理學家拉賽福發現後，在1946年首次被羅伯特威爾森提出可用在癌症治療；到2007年全世界共有28部有在運作的質子治療機，每天提供癌症患者服務；在2007年到2009年間，除傳統大型質子治療機外；再加上各家競相研發的小型質子治療機，未來質子治療機會相當普及；美國預計79年後，全美1千4百多所癌症醫院，屆時每家都會配置質子治療機。反觀國內目前兩家大型醫院積極建構質子治療設備，其它醫院亦有極高興趣；本文擬以現今所用質子治標設備為專論，探討加速質子粒子設備種類及其特性；及陸續研發中的小型質子治療機運用於癌症治療潛力，可作爲購置質子治療機之有利參考。

High-intensity, high-energy proton beams are required in various fields of science and industry, including pulsed spallation neutron experiments, nuclear-physics experiments, and nuclear-waste transmutation. We have various possible accelerator schemes for these purposes. The advantages and disadvantages of the parameter choices are summarized while emphasizing the importance of understanding the haloformation mechanisms in order to settle various controversial issues. The beam current to be accelerated is actually limited by the amount of beam loss, which is critically dependent upon the amount of beam halo, both longitudinal and transverse. The optimum design is also dependent upon the future performances of the key components, such as highintensity, low-emittance ion sources. Thus, we should concentrate our efforts on the development of these components in order to realize these machines. Some examples of the efforts being made in this direction are presented. The scope of this paper is to list various topical clinical issues concerning the design of high-intensity (typically more than 0.1mA). high-energy (more than 1GeV, but less than several 10GeV), usually Cyclotron and Synchrotron proton accelerators, and to hopefully present possible solutions, or to propose directions for further research and development. All these data are collected and courtesy from AAPM or our AEC, Hope those information do a lot of help to the new and interesting proton potential users.