Influence of Neutron Sources and 10B Concentration on Boron Neutron Capture Therapy for Shallow and Deeper Non-small Cell Lung Cancer

Abstract

Boron Neutron Capture Therapy (BNCT) is a radiotherapy that combines biological targeting and high Linear Energy Transfer (LET). It is considered a potential therapeutic approach for non-small cell lung cancer (NSCLC). It could avoid the inaccurate treatment caused by the lung motion during radiotherapy, because the dose deposition mainly depends on the boron localization and neutron source. Thus, B concentration and neutron sources are both principal factors of BNCT, and they play significant roles in the curative effect of BNCT for different cases. The purpose was to explore the feasibility of BNCT treatment for NSCLC with either of two neutron sources (the epithermal reactor at the Massachusetts Institute of Technology named "MIT source" and the accelerator neutron source designed in Argentina named "MEC source") and various boron concentrations. Shallow and deeper lung tumors were defined in the Chinese hybrid radiation phantom, and the Monte Carlo method was used to calculate the dose to tumors and healthy organs. The MEC source was more appropriate to treat the shallow tumor (depth of 6 cm) with a shorter treatment time. However, the MIT source was more suitable for deep lung tumor (depth of 9 cm) treatment, as the MEC source is more likely to exceed the skin dose limit. Thus, a neutron source consisting of more fast neutrons is not necessarily suitable for deep treatment of lung tumors. Theoretical distribution of B in tumors and organs at risk (especially skin) was obtained to meet the treatable requirement of BNCT, which may provide the references to identify the feasibility of BNCT for the treatment of lung cancer using these two neutron sources in future clinical applications.

Quantitative analysis of prompt gamma ray imaging during proton boron fusion therapy according to boron concentration

“…Originally, because we constructed the phantom for easy comparison of only imaging, more detailed construction is needed for the phantom. This cylindrical virtual phantom (material = water, diameter = 16 cm, height = 10 cm, density = 1 g/cm 3 ) included four BURs with a cylindrical pattern (diameter = 2 cm, height = 10 cm), and the boron concentration was 20 to 100 μg at intervals of 20 μg (20, 40, 60, 80, and 100 μg) because this boron concentration range has been widely used for BNCT in actual clinical applications [ 4 , 5 , 15 , 16 ]. Actual boron uptake to tumor induces the background of the small amount at the around the tumor.…”

Combined BNCT-CIRT treatment planning for glioblastoma using the effect-based optimization

“…in which Q is the boron concentration, D with superscripts boron, fn, tn, and g represent boron dose, fast neutron dose, thermal neutron dose, and gamma dose, respectively. All the fixed parameters required for the calculation of the biological weighted dose and effect in BNCT (Yu et al 2017, Bennan et al 2021 were presented in table 1.…”

“…In addition, BNCT has a high relative biological effectiveness (RBE) and is often applied in cases of recurrence following conventional radiotherapy. However, the issue of non-uniform dose distribution within tumors has consistently posed a challenge in the context of BNCT (Yu et al 2017). Multi-field neutron beams have the potential to enhance the dose distribution to large tumors (Fujimoto et al 2015, Lee et al 2017, which is similar to the principle of three-dimensional conformal radiotherapy (3D CRT).…”

The Development of Boron Analysis and Imaging in Boron Neutron Capture Therapy (BNCT)

“…Advancements such as novel scintillation crystal technology and detector electronics as well as image reconstruction algorithms for fully threedimensional PET data sets reduce the clinical imaging times while improving image quality, which leads the PET to a perfect tool for boron measuring. The method of marked radioisotopes (such as the isotopes of carbon, fluorine, oxygen, and nitrogen: 11 C, 18 F, 15 O, 13 N, etc.) were used in PET.…”

“…Radiation dosimetry plays a vital role in BNCT. Sustained efforts to improve the technologies and experiments of BNCT have involved incorporating it into general clinical therapy, such as melanoma, , glioblastoma, , head and neck tumor, − and metastatic cancer in the liver and lungs. , Currently, two drugs have been used in clinical practice for BNCT and evaluated in the experiment. The sodium mercaptoundecahydro-closo-dodecaborate (Na 2 B 12 H 11 SH), generally known as sodium borocaptate or BSH, was the first 10 B-containing compound designed for clinical therapy.…”