Design of a scintillator-based prompt gamma camera for boron-neutron capture therapy: Comparison of SrI2 and GAGG using Monte-Carlo simulation

Monte Carlo methods for medical imaging research

In radiation-based medical imaging research, computational modeling methods are used to design and validate imaging systems and post-processing algorithms. Monte Carlo methods are widely used for the computational modeling as they can model the systems accurately and intuitively by sampling interactions between particles and imaging subject with known probability distributions. This article reviews the physics behind Monte Carlo methods, their applications in medical imaging, and available MC codes for medical imaging research. Additionally, potential research areas related to Monte Carlo for medical imaging are discussed.

A compact scintillator-based detector with collimator and shielding for dose monitoring in boron neutron capture therapy

Boron neutron capture therapy exploits 10B(n,α )7Li reactions for targeted tumor destruction. In this work, we aimed at developing a dose monitoring system based on the detection of 478 keV gamma rays emitted by the reactions, which is very challenging due to the severe background present. We investigated a compact gamma-ray detector with a pinhole collimator and shielding housing. Experimental nuclear reactor measurements involved varying boron concentrations and artificial shifts of the sources. The system successfully resolved the 478 keV photopeak and detected 1 cm lateral displacements, confirming its suitability for precise boron dose monitoring.

Experimental study on Compton camera for boron neutron capture therapy applications

Boron neutron capture therapy (BNCT) is a high-dose-intensive radiation therapy that has gained popularity due to advancements in accelerator neutron sources. To determine the dose for BNCT, it is necessary to know the difficult-to-determine boron concentration and neutron fluence. To estimate this dose, we propose a method of measuring the prompt γ-rays (PGs) from the boron neutron capture reaction (BNCR) using a Compton camera. We performed a fundamental experiment to verify basic imaging performance and the ability to discern the PGs from 511 keV annihilation γ-rays. A Si/CdTe Compton camera was used to image the BNCR and showed an energy peak of 478 keV PGs, separate from the annihilation γ-ray peak. The Compton camera could visualize the boron target with low neutron intensity and high boron concentration. This study experimentally confirms the ability of Si/CdTe Compton cameras to image BNCRs.

Clinical Viability of Boron Neutron Capture Therapy for Personalized Radiation Treatment

Simple Summary

Usually, for dose planning in radiotherapy, the tumor is delimited as a volume on the image of the patient together with other clinical considerations based on populational evidence. However, the same prescription dose can provide different results, depending on the patient. Unfortunately, the biological aspects of the tumor are hardly considered in dose planning. Boron Neutron Capture Radiotherapy enables targeted treatment by incorporating boron-10 at the cellular level and irradiating with neutrons of a certain energy so that they produce nuclear reactions locally and almost exclusively damage the tumor cell. This technique is not new, but modern neutron generators and more efficient boron carriers have reactivated the clinical interest of this technique in the pursuit of more precise treatments. In this work, we review the latest technological facilities and future possibilities for the clinical implementation of BNCT and for turning it into a personalized therapy.

Abstract

Boron Neutron Capture Therapy (BNCT) is a promising binary disease-targeted therapy, as neutrons preferentially kill cells labeled with boron (¹⁰B), which makes it a precision medicine treatment modality that provides a therapeutic effect exclusively on patient-specific tumor spread. Contrary to what is usual in radiotherapy, BNCT proposes cell-tailored treatment planning rather than to the tumor mass. The success of BNCT depends mainly on the sufficient spatial biodistribution of ¹⁰B located around or within neoplastic cells to produce a high-dose gradient between the tumor and healthy tissue. However, it is not yet possible to precisely determine the concentration of ¹⁰B in a specific tissue in real-time using non-invasive methods. Critical issues remain to be resolved if BNCT is to become a valuable, minimally invasive, and efficient treatment. In addition, functional imaging technologies, such as PET, can be applied to determine biological information that can be used for the combined-modality radiotherapy protocol for each specific patient. Regardless, not only imaging methods but also proteomics and gene expression methods will facilitate BNCT becoming a modality of personalized medicine. This work provides an overview of the fundamental principles, recent advances, and future directions of BNCT as cell-targeted cancer therapy for personalized radiation treatment.