Barendsen G W
Radiol Clin (Basel). 1977;46(5):380-9.
The application of fast neutrons, negative pions or heavy ions will only provide an advantage for the radiotherapy of cancer if, in comparison with conventional radiation, e.g., X-rays, gamma rays and electrons, better depth-dose and collimation characteristics or specific radiobiological dose-response relationships result in greater local control probabilities for tumours without increased frequencies of severe normal tissue damage. Differences in intrinsic radiosensitivity and the presence of hypoxic cells are considered to be the main factors which can cause values of the relative biological effectiveness (RBE) for responses of tumours to be larger than RBE values for normal tissue tolerance. Clinical studies on lung metastases irradiated with single doses of 15 MeV neutrons indicate that RBE values for tumour growth delay can vary between 1.2 and 4.0, while RBE values for damage to several normal tissues are estimated from data on a few animal tissues to be approximately 2.5.
与传统辐射（如X射线、γ射线和电子）相比，如果快中子、负π介子或重离子的应用能产生更好的深度剂量和准直特性，或特定的放射生物学剂量反应关系，从而在不增加严重正常组织损伤频率的情况下提高肿瘤的局部控制概率，那么它们在癌症放射治疗中才具有优势。内在放射敏感性的差异和缺氧细胞的存在被认为是导致肿瘤反应的相对生物效应（RBE）值大于正常组织耐受性RBE值的主要因素。对单剂量15 MeV中子照射肺转移瘤的临床研究表明，肿瘤生长延迟的RBE值在1.2至4.0之间变化，而根据少数动物组织的数据估计，几种正常组织损伤的RBE值约为2.5。
