Laramore G E, Wootton P, Livesey J C, Wilbur D S, Risler R, Phillips M, Jacky J, Buchholz T A, Griffin T W, Brossard S
Department of Radiation Oncology, University of Washington Medical Center, Seattle 98195.
Int J Radiat Oncol Biol Phys. 1994 Mar 30;28(5):1135-42. doi: 10.1016/0360-3016(94)90487-1.
For many years neutron radiation has been used to treat malignant disease both as fast neutron radiotherapy and as thermal neutron induced boron neutron capture therapy (BNCT). To date, these two approaches have been used independently of one another due to the large difference in neutron energies each employs. In this paper we discuss the potential application of BNCT to enhance the therapeutic effectiveness of a fast neutron radiotherapy beam.
Measurements are presented for the thermal neutron component that is spontaneously developed as the University of Washington fast neutron radiotherapy beam penetrates a water phantom. The biological effect of this thermalized component on cells "tagged" with boron-10 (10B) is modeled mathematically and the expected change in cell survival calculated. The model is then extended to estimate the effect this enhanced cell killing would have for increased tumor control.
The basic predictions of the model on changes in cell survival are verified with in vitro measurements using the V-79 cell line. An additional factor of 10-100 in tumor cell killing appears achievable with currently available 10B carriers using our present neutron beam. A Poisson model is then used to estimate the change in tumor control this enhanced cell killing would produce in various clinical situations and the effect is sufficiently large so as to be clinically relevant. It is also demonstrated that the magnitude of the thermalized component can be increased by a factor of 2-3 with relatively simple changes in the beam generating conditions.
BNCT may provide a means of enhancing the therapeutic effectiveness of fast neutron radiotherapy in a wide variety of clinical situations and is an area of research that should be aggressively pursued.
多年来，中子辐射已被用于治疗恶性疾病，包括快中子放射治疗和热中子诱发的硼中子俘获治疗（BNCT）。迄今为止，由于这两种方法所使用的中子能量差异巨大，它们一直是相互独立使用的。在本文中，我们讨论了BNCT在提高快中子放射治疗束治疗效果方面的潜在应用。
给出了华盛顿大学快中子放射治疗束穿透水模体时自发产生的热中子成分的测量结果。对这种热化成分对用硼 - 10（¹⁰B）“标记”的细胞的生物学效应进行了数学建模，并计算了细胞存活的预期变化。然后扩展该模型以估计这种增强的细胞杀伤对提高肿瘤控制的影响。
使用V - 79细胞系的体外测量验证了该模型对细胞存活变化的基本预测。使用我们目前的中子束，使用现有的¹⁰B载体在肿瘤细胞杀伤方面似乎可实现额外10 - 100倍的效果。然后使用泊松模型估计这种增强的细胞杀伤在各种临床情况下对肿瘤控制的变化，其效果足够大，具有临床相关性。还证明，通过对束流产生条件进行相对简单的改变，热化成分的幅度可以增加2 - 3倍。
BNCT可能提供一种在各种临床情况下提高快中子放射治疗效果的方法，是一个应积极开展研究的领域。
