A Semi-Empirical Method of Treatment Planning for Boron Neutron Capture Therapy

Abstract

In BNCT the total dose delivered to the tumor and to the healthy tissue depends on several factors. Knowledge of the ¹⁰B distribution, the thermal neutron fluence, the epithermal neutron fluence, the fast neutron fluence and the photon dose is necessary for the calculation of the total dose delivered to all points of interest in the patient. Calculations using either Monte Carlo or deterministic codes, both commonly applied in reactor physics for neutron and photon transport calculations, have been proposed for treatment planning of BNCT^1,2. Due to the large calculation times needed for these kinds of calculations, such a procedure for external photon beam treatment planning is not yet available for daily usage in radiotherapy institutions³. Therefore, little experience has been gained with these procedures in clinical situations. External photon beam treatment planning is currently based on empirical knowledge of the dose distributions under reference conditions. Beam parameters measured in a large cubical water-phantom are corrected with deterministic algorithms to calculate dose distributions in other geometries³. Treatment planning of BNCT based on Monte Carlo calculations as well as using such a semi-empirical approach is in development in the Petten-Amsterdam BNCT group⁴. It is the purpose of this work to investigate wether the relatively simple semi-empirical approach can be used for the treatment planning of BNCT using an epithermal neutron beam.