Yanch J C, Zamenhof R G
Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge 02139.
Radiat Res. 1992 Sep;131(3):249-56.
Interstitial and intracavity 252Cf sources have been used to treat a number of tumor types with encouraging results. In particular these tumors include a variety of cervical, head-and-neck, and oral-cavity cancers and possible malignant gliomas. As a neutron source, 252Cf offers certain theoretical advantages over photon therapy (i.e., in treating tumors with significant hypoxic or necrotic components). With the recent availability of 10B-labeled tumor-seeking compounds, the usefulness of 252Cf may be further improved by augmenting the 252Cf dose to the tumor with an additional dose due to the fission (following thermal neutron capture) of 10B located in the tumor itself. While the high mean neutron energy permits 252Cf to deliver a high-LET, low-OER dose to the tumor on a macroscopic scale, thermalization of neutrons followed by 10B capture may augment this dose at the cellular level if adequate loading of tumor cells with 10B is possible. This paper presents results of a Monte Carlo simulation study investigating the dosimetric characteristics of linear 252Cf sources both with and without the quantitative increase in tumor dose possible with the addition of 10B. Results are displayed in the form of "along and away" tables and dose profiles in a water phantom. Comparisons of Monte Carlo results with experimental and analytical dosimetry data available in the literature are also presented.
间质内和腔内252Cf源已被用于治疗多种肿瘤类型，并取得了令人鼓舞的结果。特别是这些肿瘤包括各种宫颈癌、头颈癌和口腔癌以及可能的恶性胶质瘤。作为一种中子源，252Cf相对于光子疗法具有某些理论优势（即，在治疗具有显著缺氧或坏死成分的肿瘤时）。随着最近10B标记的肿瘤寻靶化合物的可得性，252Cf的效用可能会通过以下方式进一步提高：由于位于肿瘤本身的10B的裂变（热中子俘获后），向肿瘤增加额外剂量，从而增加252Cf对肿瘤的剂量。虽然高平均中子能量使252Cf能够在宏观尺度上向肿瘤提供高传能线密度、低氧增强比的剂量，但如果肿瘤细胞能够充分负载10B，则中子热化后再俘获10B可能会在细胞水平上增加该剂量。本文介绍了一项蒙特卡罗模拟研究的结果，该研究调查了线性252Cf源在添加10B可能使肿瘤剂量定量增加和不增加这两种情况下的剂量学特征。结果以“沿轴和离轴”表格的形式以及水模体中的剂量分布图显示。还给出了蒙特卡罗结果与文献中可用的实验和分析剂量学数据的比较。
