Floyd J. Wheeler

Physics Parameters for an Epithermal—Neutron Beam at the Georgia Institute of Technology

Boron Neutron Capture Therapy (BNCT) research in the United States has focused on the use of epithermal (0.5 eV to 10 key) neutron beams for treatment of certain highly-malignant primary brain tumors and possibly for treatment of metastatic malignant melanoma. Various types of epithermal neutron sources for BNCT have been proposed over the years. Reactor-based sources, accelerator-based sources, and radioactive neutron sources have all been extensively examined. The first practical, large-scale, epithermal neutron beam for BNCT was installed at the Brookhaven Medical Research Reactor (BMRR)1. This beam was designed and constructed in a cooperative effort between Brookhaven National Laboratory (BNL) and the Idaho National Engineering Laboratory (INEL). It has been used extensively for BNCT research activities conducted by INEL, BNL, and others.

Improvements in Patient Treatment Planning Systems

The Boron Neutron Capture Therapy, Radiation treatment planning environment (BNCT_Rtpe) software system is used to develop treatment planning information’. In typical use BNCT_Rtpe consists of three main components: (1) Semiautomated geometric modeling of objects (brain, target, eyes, sinus) derived from MRI, CT, and other medical imaging modalities, (2) Dose computations for these geometric models with rtt_MC, the INEL Monte Carlo radiation transport computer code, and (3) Dose contouring overlaid on medical images as well as generation of other dose displays. We continue to develop a planning system based on three-dimensional image-based reconstructions using Bspline surfaces. Even though this software is in an experimental state, it has been applied for large animal research and for an isolated case of treatment for a human glioma. Radiation transport is based on Monte Carlo, however there will be implementations of faster methods (e.g. diffusion theory) in the future. The important thing for treatment planning is the output which must convey, to the radiologist, the deposition of dose to healthy and target tissue. Many edits are available such that one can obtain contours registered to medical image, dose/volume histograms and most information required for treatment planning and response assessment. Recent work has been to make the process more automatic and easier to use. The interface, now implemented for contouring and reconstruction, utilizes the Xwindowing system and the MOTIF graphical users interface for effective interaction with the planner. Much work still remains before the tool can be applied in a routine clinical setting.

Neutron sources for BNCT using low-power research reactors or compact charged particle accelerators

Since 1986, the Idaho National Engineering Laboratory (INEL) has been involved in the development of epithermal neutron sources for BNCT. The INEL effort was instrumental in the implementation of an epithermal neutron beam at the Brookhaven Medical Research Reactor at Brookhaven National Laboratory. Recently, the INELs effort has been directed toward developing advanced filter designs for use with low- power research reactors such as the 250W and 1MW class TRIGA reactors which are located at various sites and universities throughout the world. This work has focused on utilizing advanced filter materials that more effectively reduce fast neutron contamination in the epithermal neutron beam and at the same time optimize neutron economy. The INEL has also been involved in developing two concepts of producing neutron sources for BNCT using charged particle accelerators. The first concept involves the use of an electron accelerator/photoneutron source. The second concept involves the use of a charged particle beam in which the particle energy is just above the threshold energy of the reaction. This paper will review the progress made by INEL in modifying the WSU TRIGA reactor and conceptual development of an electron accelerator based photoneutron source for BNCT. The near threshold particle accelerator development will be discussed in a separate paper.

SERA: Simulation Environment for Radiotherapy Applications - Users Manual Version 1CO

This document is the user manual for the Simulation Environment for Radiotherapy Applications (SERA) software program developed for boron-neutron capture therapy (BNCT) patient treatment planning by researchers at the Idaho National Engineering and Environmental Laboratory (INEEL) and students and faculty at Montana State University (MSU) Computer Science Department. This manual corresponds to the final release of the program, Version 1C0, developed to run under the RedHat Linux Operating System (version 7.2 or newer) or the Solaris™ Operating System (version 2.6 or newer). SERA is a suite of command line or interactively launched software modules, including graphical, geometric reconstruction, and execution interface modules for developing BNCT treatment plans. The program allows the user to develop geometric models of the patient as derived from Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) images, perform dose computation for these geometric models, and display the computed doses on overlays of the original images as three dimensional representations. This manual provides a guide to the practical use of SERA, but is not an exhaustive treatment of each feature of the code.

Determination of Fast—Neutron Dose Distributions in the Canine Central Nervous System

The Idaho National Engineering Laboratory (INEL) Center for Boron Neutron Capture Therapy (BNCT) Measurement and Development conducts, sponsors, and coordinates research and development efforts in a variety of BNCT-related areas. Current activities include an ongoing series of large-animal (canine) model irradiation experiments conducted in collaboration with the Washington State University School of Veterinary Medicine1. These experiments employ the epithermal-neutron beam at the Brookhaven Medical Research Reactor (BMRR)2 and have the purpose of determining normal tissue tolerance and spontaneous brain tumor response to the unique mix of radiation components that characterize BNCT.

Post Treatment Dose Distribution Evaluation for a Recent NCT Patient

As a prelude to establishing, (1) criteria for selection of Boron Neutron Capture Therapy (BNCT) epithermal beam clinical trial patients and (2) treatment planning strategies, posttreatment evaluations of dose distributions in several BNCT patients are being done using the Idaho National Engineering Laboratory (INEL) BNCT Program’s patient treatment planning software (bnct_edit and rtt_MC)1,2