Comparison of Dose Distributions with ¹⁰Boron Augmented Sources of ²⁵²Cf Obtained by Monte Carlo Simulation and by Experimental Measurement

Abstract

Intracavity and interstitial ²⁵²Cf implants have been used to treat a number of tumor types including gynecological tumors and glioblastoma^1,2,3, the former with encouraging results. 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-labelled tumor seeking compounds, the usefulness of ²⁵²Cf may be further improved by augmenting the ²⁵²Cf dose to 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 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 which investigates the dosimetric characteristics of linear ²⁵²Cf sources and the quantitative increase in tumor dose possible with the addition of ¹⁰B. Comparison of the presented Monte Carlo results with experimental and analytic dosimetry data presented in the literature will also be made.