Brizel David M
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
J Clin Oncol. 2007 Sep 10;25(26):4084-9. doi: 10.1200/JCO.2007.11.5816.
The concept of the therapeutic ratio (TR) is central to understanding the rationale for using radioprotectors. The TR relates tumor control probabilities and normal tissue complication probabilities to one another. An ideal radioprotector will reduce the latter without compromising the former. It should also be minimally toxic itself. Radioprotective strategies can be classified under the categories of protection, mitigation, and treatment. Protectors are administered before radiotherapy (RT) and are designed to prevent radiation-induced injury. Amifostine is the prototype drug. Mitigants are administered after RT but before the phenotypic expression of injury and are intended to ameliorate injury. Palifermin can be considered as the prototype mitigant. Treatment is a strategy that is predominantly palliative and supportive in nature. Pharmacologic radioprotective strategies should be integrated with physical strategies such as intensity-modulated radiotherapy to realize their maximum clinical potential.
治疗比（TR）的概念对于理解使用辐射防护剂的基本原理至关重要。治疗比将肿瘤控制概率与正常组织并发症概率相互关联。理想的辐射防护剂应在不影响前者的情况下降低后者。其自身毒性也应降至最低。辐射防护策略可分为防护、减轻和治疗三类。防护剂在放射治疗（RT）前给药，旨在预防辐射诱导的损伤。氨磷汀是原型药物。减轻剂在放射治疗后但在损伤表型表达前给药，旨在减轻损伤。帕利夫明可被视为原型减轻剂。治疗是一种本质上主要为姑息性和支持性的策略。药理学辐射防护策略应与物理策略如调强放射治疗相结合，以实现其最大临床潜力。
