Hall E J
J Can Assoc Radiol. 1975 Mar;26(1):3-14.
The introduction of high LET radiations into radiotherapy is an exciting development. Neutron facilities are already in clinical use in England and the United States, while machines to produce negative pi mesons and high energy heavy ions are in an advanced stage of development in Canada, the United States and Europe. The state of the art at each of these installations is reviewed. The therapeutic merits of various heavy particles are compared with conventional photon beams. Lowering the OER (oxygen enhancement ratio) and improvement in the depth dose pattern are the principal advantages sought. Neutrons result in a somewhat lower OER but offer depth-dose patterns that are barely the equal of x- and gamma-rays. Protons by contrast produce excellent dose distributions, but no reduction of OER. Negative pi mesons improve both depth dose pattern and OER to some extent. High energy heavy nuclei show the greatest promise as far as lowering the OER is concerned, but will probably not equal pions in depth dose pattern. More radiobiologic data are urgently needed for all of these new radiation modalities.
将高传能线密度辐射引入放射治疗是一项令人兴奋的进展。中子设备已在英国和美国投入临床使用，而用于产生负π介子和高能重离子的机器在加拿大、美国和欧洲正处于先进的研发阶段。本文对这些装置各自的技术现状进行了综述。将各种重粒子的治疗优势与传统光子束进行了比较。降低氧增强比（OER）和改善深度剂量分布是主要追求的优势。中子导致的OER略低，但提供的深度剂量分布几乎与X射线和γ射线相当。相比之下，质子产生优异的剂量分布，但不会降低OER。负π介子在一定程度上改善了深度剂量分布和OER。就降低OER而言，高能重核显示出最大的前景，但在深度剂量分布方面可能无法与π介子相比。对于所有这些新的辐射模式，迫切需要更多的放射生物学数据。
