Accelerator-based Boron Neutron Capture Therapy Research Articles

CTNI-56. A PHASE II CLINICAL TRIAL USING ACCELERATOR-BASED BNCT SYSTEM FOR REFRACTORY RECURRENT HIGH-GRADE MENINGIOMA

Abstract BACKGROUND Boron neutron capture therapy (BNCT) is tumor-selective particle radiation. Recently accelerator-based neutron sources (ABNS) have been developed for clinical trials to obtain on-label use, i.e. new drug approval for malignant gliomas. Recently Japanese regulatory authority has just given this permission for H&N cancers. Recurrent high-grade meningiomas (HGM) are difficult to control. We have applied reactor-based BNCT for 46 cases of refractory HGM. All cases showed good tumor shrinkage with good local control. PURPOSES Based on these situations, we proposed “A phase II clinical trial using accelerator-based BNCT system for refractory recurrent HGM” for AMED in Japan which is similar to NIH in USA. This proposal was successfully accepted. DESIGN We prepared 2 study groups, BNCT test treatment group and control best supportive care group, for RCT. PFS and OS were set-up as primary and secondary endpoints, respectively. Rescue BNCT is allowed for control group patients, if they showed PD during observation. Modified Macdonald criteria is adopted for assessment. Hypothesized PFS of treatment group and control group was 5 months and 24 months, respectively. The trial started in August 2019. METHODS Twelve BNCT and 6 control subjects will be included. Patients’ eligibility criteria is recurrent HGM after some radiotherapy. Cyclotron-based ABNS system is used for neutron source. Neutron-irradiation time is determined not to exceed to 7.5 Gy-Eq for scalp dose which was referencing preceding phase I trial for malignant gliomas. PROGRESS As of April 2020, 4 subjects were included, 3 for BNCT treatment group, 1 for control best supportive care group. The control subject showed PD during one month observation and rescue treatment showed PR. Treatment group 3 cases showed more than SD. CONCLUSION We started this RCT and will introduce the interim report of this clinical trial in the meeting.

Design of the input power coupler for Boron Neutron Capture Therapy Drift Tube Linac

An accelerator-based Boron Neutron Capture Therapy (BNCT) facility has been built at the campus of China Spallation Neutron Source (CSNS). To upgrade it, a Drift Tube Linac (DTL) is designed to provide a 40 mA, 25% duty factor, 10.1 MeV beam for the target. Two opposing power couplers are employed to deliver forward peak power up to 640 kW for the beam and DTL cavity. A new coaxial power coupler with a single Tristan type window is designed to meet the power and coupling coefficient requirements. In this paper, the detailed RF optimization process of the coupler is described. According to the RF simulation results, the multipacting (MP) phenomenon at critical locations is simulated by the CST PS (Particle Studio). Simulations of thermal and mechanical are also carried out, the cooling design to provide a large margin for RF heating is performed based on the simulation results.

A bi-tapered and air-gapped beam shaping assembly used for AB-BNCT

The 7Li(p,n)7Be reaction, which leads to a soft neutron field, is often chosen as the neutron producing reaction used for accelerator-based boron neutron capture therapy (AB-BNCT). This study aims to design a compact beam shaping assembly (BSA) and auxiliary system for a 7Li(p,n)7Be reaction-based neutron source and to evaluate the relationship between the BSA design and the consequent neutron beam quality for further optimization.In this study, five types of moderator shapes for the BSA model were designed. Both the in-air and in-phantom figures of merit were considered to evaluate the performance of the BSA designs. It was found that the BSA with a bi-tapered and air-gapped design could generate a high-intensity epithermal neutron beam, which could be used to treat deep-seated brain tumors within a reasonable time.

Status of low-energy accelerator-based BNCT worldwide and in Argentina

Existing and active low-energy Accelerator-Based BNCT programs worldwide will be reviewed and compared. In particular, the program in Argentina will be discussed which consists of the development of an Electro-Static-Quadrupole (ESQ) Accelerator-Based treatment facility. The facility is conceived to operate with the deuteron-induced reactions 9Be(d,n)10B and 13C(d,n)14N at 1.45 MeV deuteron energy, as neutron sources. Neutron production target development status is specified. The present status of the construction of the new accelerator development laboratory and future BNCT centre is shown.

Comparison of different methods for the shielding analysis of an AB-BNCT facility based on the Be(p,xn) reaction with 30-MeV protons

Five shielding calculation methods were employed to estimate the dose rate distribution around an accelerator-based boron neutron capture therapy facility. Their performances were compared in terms of accuracy and efficiency. The results indicate that the hybrid deterministic/Monte Carlo method is the most efficient in the context of accurate modeling and simulation, whereas the analytical approximation with pre-generated source terms and attenuation lengths is preferable in the design phase because of its simplicity and ease of verification while retaining a reasonable accuracy.

Neutron yields of Be-9(p,xn) reactions and beam characterization for accelerator-based boron neutron capture therapy facility using MCNP6, PHITS, and GEANT4 simulation results

Neutron yields from 9Be(p,xn) reactions with a 2-cm thick beryllium target bombarded by proton beams of 5, 6, 7, 8, 9, and 10 MeV were investigated. Neutron beam characteristics through a pilot design of beam shaping assembly were calculated by using MCNP6, PHITS, and GEANT4. The neutron yield with a 10 MeV beam by MCNP6 was 7.7 times larger than values by the other codes, but close to the experimental data. The neutron spectrum and directionality were different among the codes. These differences could stem from different cross-section libraries and models used in the codes. The epithermal flux at the beam irradiation port by MCNP6 was 1.4 × 109 cm−2 s−1 for a proton current of 8 mA hitting the target. The ratio of thermal and epithermal flux was less than 0.01 and the forward directionality was 0.78. However, we suggest a new criterion regarding a ratio of fast and epithermal flux.

Boron neutron capture therapy for malignant brain tumors.

Boron neutron capture therapy (BNCT) is tumor-selective particle radiation therapy that depends on the nuclear capture and fission reactions. These reactions occur when a non-radioactive boron isotope (10B) is irradiated with low-energy thermal neutrons to yield high linear energy transfer α-particles and lithium-7 nuclei within a limited path length, i.e., an almost one-cell diameter. The 10B-containing cells can then be selectively destroyed by these potent particles. BNCT has been applied in the field of malignant brain tumors for newly diagnosed and recurrent malignant gliomas (chiefly glioblastomas). These clinical applications of BNCT have been performed with reactor-based neutron sources over the past decades. We also applied reactor-based BNCT for 58 newly diagnosed glioblastomas and 68 recurrent malignant gliomas including 52 glioblastomas. In this review article, we summarize the clinical results from the literature concerning BNCT for these high-grade gliomas (including our research). We also applied reactor-based BNCT for 46 cases of recurrent and refractory high-grade meningiomas, and some of the results will be presented herein. In Japan, neutron sources have been shifted from reactors to accelerators. Phase 1 and 2 clinical trials have been performed for recurrent malignant gliomas using accelerator-based neutron sources, and now fortunately, a cyclotron-based neutron generator has been approved as a medical device by Japanese regulatory authority, as the world's first accelerator-based BNCT system for medical use. We also discuss the future prospects of accelerator-based BNCT in hospitals as therapy for malignant brain tumors.

Design of a BNCT irradiation room based on proton accelerator and beryllium target

Preliminary studies for the design of an accelerator-based BNCT clinical facility are presented. The Beam Shaping Assembly neutron activation was evaluated experimentally and with Monte Carlo simulations. The activations of patient, air and walls in the room, the absorbed doses by the patient and the in-air dose distributions were evaluated. Based on these calculations, different walls compositions were tested to optimize the environmental conditions. Borated concrete, advantageously reducing the thermal flux in the room, was proven the best choice.

Accelerator-based BNCT in rescue treatment of patients with recurrent GBM: A multicenter phase II study.

2536 Background: Boron neutron capture therapy (BNCT) is tumor-selective particle radiation and theoretically efficacious especially for tumors with infiltrative nature, such as glioblastoma (GBM). The aim of this study is to assess safety and efficacy of accelerator-based BNCT (AB-BNCT) using cyclotron-based neutron generator, BNCT30, and 10B-boronophenylalanine (borofalan(10B)) agent, SPM-011, in patients with recurrent malignant gliomas, chiefly GBM. Methods: The multi-institutional open-label, phase II clinical trial for recurrent 27 cases of malignant gliomas (MG) (24 cases were GBM) was conducted with above mentioned AB-BNCT system, using 500mg/kg of SPM-011 (study code, JG002). The patients were enrolled from February 2016 to June 2018. The inclusion criteria are bevacizumab-naïve MG, recurrent after standard treatment composed of XRT and chemotherapy with TMZ. Neutron-irradiation time were determined not to exceed to 8.5 Gy-Eq for scalp dose which was decided by preceding phase I trial. Primary endpoint was 1-year survival rate and secondary ones were median overall survival (mOS), median progression free survival (mPFS) and so on. The results were compared to previous Japanese domestic bevacizumab trial for recurrent GBM (JO22506) which had the similar inclusion criteria with JG002. Results: 1-year survival rate and mOS of recurrent GBM cases in JG002 was 79.2% (95% CI:57.0-90.8) and 18.7 months (95% CI:12.9-23.4) (data cutoff = 20 Jun 2019) respectively, while those of JO22506 was 34.5% (90% CI:20.0-49.0) and 10.5 months (95% CI:8.2-12.4), respectively. Median PFS of JG002 and JO22506 were 0.9 and 3.3 months, respectively. Most important adverse event in JG002 was brain edema. 21 out of 27 cases were treated with bevacizumab after progress disease. Conclusions: AB-BNCT demonstrated acceptable safety and prolonged survival for recurrent MG chiefly GBM. AB-BNCT might produce brain edema somewhat after the treatment, which might be the unavoidable adverse event of re-irradiation for recurrent MG, however that seemed to be controlled with bevacizumab. Clinical trial information: JapicCTI-194742 . [Table: see text]

Implications of radiation microdosimetry for accelerator-based boron neutron capture therapy: a radiobiological perspective.

Boron neutron capture therapy (BNCT) has great potential to selectively destroy cancer cells while sparing surrounding normal cells. The basic concept of BNCT was developed in the 1930s, but it has not yet been commonly used in clinical practice, even though there is now a large number of experimental and translational studies demonstrating its marked therapeutic potential. With the development of neutron accelerators that can be installed in medical institutions, accelerator-based BNCT is expected to become available at several medical institutes around the world in the near future. In this commentary, from the point of view of radiation microdosimetry, we discuss the biological effects of BNCT, especially the underlying mechanisms of compound biological effectiveness. Radiobiological perspectives provide insight into the effectiveness of BNCT in creating a synergy effect in the field of clinical oncology.

Accelerator-based boron neutron capture therapy for malignant glioma: a pilot neutron irradiation study using boron phenylalanine, sodium borocaptate and liposomal borocaptate with a heterotopic U87 glioblastoma model in SCID mice

Purpose: To evaluate the efficacy of boron neutron capture therapy (BNCT) for a heterotopic U87 glioblastoma model in SCID mice using boron phenylalanine (BPA), sodium borocaptate (BSH) and liposomal BSH as boron compounds at a unique, accelerator-based neutron source.Materials and methods: Glioblastoma models were obtained by subcutaneous implantation of U87 cells in the right thighs of SCID mice before administration of 350 mg/kg of BPA (BPA-group), 100 mg/kg of BSH (BSH-group) or 100 mg/kg of BSH in PEGylated liposomes (liposomal BSH-group) into the retroorbital sinus. Liposomes were prepared by reverse-phase evaporation. Neutron irradiation was carried out at a proton accelerator with a lithium target developed for BNCT at the Budker Institute of Nuclear Physics, Novosibirsk, Russian Federation. A proton beam current integral of 3 mA/h and energy of 2.05 MeV were used for neutron generation.Results: Boron compound accumulation in tumor tissues at the beginning of irradiation was higher in the BPA group, followed by the Liposomal BSH and BSH groups. Tumor growth was significantly slower in all irradiated mice from the 7th day after BNCT compared to untreated controls (p < .05). Tumor growth in all treated groups showed no large variation, apart from the Irradiation only group and the BPA group on the 7th day after BNCT. The overall trend of tumor growth was clear and the differences between treatment groups became significant from the 50th day after BNCT. Tumor growth was significantly slower in the Liposomal BSH group compared to the Irradiation only group on the 50th (p = .012), 53rd (p = .005), and the 57th (p = .021) days after treatment. Tumor growth in the Liposomal BSH group was significantly different from that in the BPA group on the 53rd day after BNCT (p = .021) and in the BSH group on the 50th (p = .024), 53rd (p = .015), and 57th (p = .038) days after BNCT. Skin reactions in the form of erosions and ulcers in the tumor area developed in treated as well as untreated animals with further formation of fistulas and necrotic decay cavities in most irradiated mice.Conclusions: We observed a tendency of BNCT at the accelerator-based neutron source to reduce or suspend the growth of human glioblastoma in immunodeficient animals. Liposomal BSH showed better long-term results compared to BPA and non-liposomal BSH. Further modifications in liposomal boron delivery are being studied to improve treatment outcomes.

Detection of alpha and 7Li particles from 10B(n, α)7Li reactions using a combination of CR-39 nuclear track detector and potassium hydroxide-ethanol-water solution in accelerator-based neutron fields

We investigated the optimum etching condition for potassium hydroxide-ethanol–water solution (PEW) to detect only alpha and 7Li particles from 10B(n, α)7Li reactions registered in a CR-39 plastic nuclear track detector. The background recoil protons, which are induced by fast neutrons with energies of <2 MeV produced by 9Be(p, n)9B reactions in accelerator-based neutron sources, were discriminated by the desensitization effect with PEW. We found that an ethanol concentration of ≥15 wt% in a PEW solution discriminated recoil proton tracks with energies of <2 MeV. The optimized conditions will be applicable for evaluating dose distribution in tissue in accelerator-based boron neutron capture therapy.

ACT-02 BORON NEUTRONS CAPTURE THERAPY FOR RECURRENT HIGH-GRADE MENINGIOMAS, FROM REACTOR TO ACCELERATOR

INTRODUCTIONRecurrent high-grade meningiomas (rHGM) are difficult to control. We have applied tumor-selective particle radiation, reactor-based boron neutron capture therapy (BNCT) with excellent tumor control.METHODSForty-six recurrent and treatment-refractory high grade meningiomas were treated with reactor-based BNCT by Osaka Medical College (OMC) and Kyoto University Research Reactor team collaboratively until February 2019. Tumor shrinkage, overall survival (OS), progression free survival (PFS), Lesion/Normal (L/N) ratio in boronophenylalanine positron emission tomography (BPA-PET) and causes of treatment failures are analyzed.RESULTSSubjects had been almost always treated heavily, high-risk patients for prognosis. They were received surgery 3 times and some radiotherapy 2 times averagely, prior to BNCT. All cases responded well and markedly shrunk by BNCT. The mean L/N ratio in BPA-PET was 4.0 which is higher than glioblastomas. Two-year PFS was 49.0% (95% CI: 28.84–66.49). Unfortunately follow-up was insufficient and 2 year OS was very similar to 2 year PFS. Treatment failures were observed as recurrence out of fields of neutron irradiation, systemic metastasis and in field local recurrence almost equally.SUMMARY AND PROSPECTSMedian PFS and OS of rHGM are 5 months and 2 years respectively in literatures. We achieved relatively favorable results by reactor-based BNCT. On the other hand, we performed accelerator-based BNCT clinical trial for recurrent glioblastomas steadily first in the world. Based on these backgrounds, we applied investigator-lead, clinical trial of accelerator-based BNCT for rHGM as RCT design. Government (PMDA and AMED) has approved our proposal. We start this trial with the primary endpoint as PFS, from August 2019. Treatment arm is BNCT and control one is best-supportive care. If the subjects in control arm show progress disease in follow-up, they can be treated by BNCT as rescue treatments. We will introduce details of this trial in our presentation.

Characterization of the relationship between neutron production and thermal load on a target material in an accelerator-based boron neutron capture therapy system employing a solid-state Li target.

An accelerator-based boron neutron capture therapy (BNCT) system that employs a solid-state Li target can achieve sufficient neutron flux derived from the 7Li(p,n) reaction. However, neutron production is complicated by the large thermal load expected on the target. The relationship between neutron production and thermal load was examined under various conditions. A target structure for neutron production consists of a Li target and a target basement. Four proton beam profiles were examined to vary the local thermal load on the target structure while maintaining a constant total thermal load. The efficiency of neutron production was evaluated with respect to the total number of protons delivered to the target structure. The target structure was also evaluated by observing its surface after certain numbers of protons were delivered. The yield of the sputtering effect was calculated via a Monte Carlo simulation to investigate whether it caused complications in neutron production. The efficiency of neutron production and the amount of damage done depended on the proton profile. A more focused proton profile resulted in greater damage. The efficiency decreased as the total number of protons delivered to the target structure increased, and the rate of decrease depended on the proton profile. The sputtering effect was not sufficiently large to be a main factor in the reduction in neutron production. The proton beam profile on the target structure was found to be important to the stable operation of the system with a solid-state Li target. The main factor in the rate of reduction in neutron production was found to be the local thermal load induced by proton irradiation of the target.

Design and construction of an accelerator-based boron neutron capture therapy (AB-BNCT) facility with multiple treatment rooms at the Southern Tohoku BNCT Research Center

Installation of an accelerator-based boron neutron capture therapy (AB-BNCT) system was started in April 2014 at the Southern Tohoku BNCT Research Center (STBRC), and clinical trials began in January 2016. There are two treatment rooms, which have same specifications, and the beam quality equivalency was confirmed both rooms. Here, we describe the design and construction of the first hospital-based AB-BNCT facility in the world with multiple treatment rooms.

1135P - Updated results of a phase II study evaluating accelerator-based boron neutron capture therapy (AB-BNCT) with borofalan(10B) (SPM-011) in recurrent squamous cell carcinoma (R-SCC-HN) and recurrent and locally advanced non-SCC (R/LA-nSCC-HN) of the head and neck

BackgroundBNCT is a unique cancer treatment technique in which tumor cells are irradiated from the inside with heavy particles produced by 10B(n,α)7Li nuclear transmutation reaction of boron atom and neutron. A next-generation AB-BNCT system that does not require a nuclear reactor has been developed, and it has become possible to perform BNCT in urban hospitals along with stable supply of borofalan (10B) supported by high 10B concentration technology. MethodsIn this world-first, open-label phase II trial of AB-BNCT, patients (pts) with previously irradiated, platinum-resistant R-SCC-HN or with R/LA-nSCC-HN were administered with borofalan(10B) at 200mg/kg/h intravenously for 2hours, followed by neutron irradiation with continuous infusion at 100mg/kg/h. The irradiated dose for tumor was determined passively as a mucosal maximum dose was given 12Gy-Eq. Primary endpoint was objective response rate (ORR) by central review. Updated efficacy and safety analysis are presented here (data cut off: 5 April 2019). ResultsEight R-SCC-HN and thirteen R/LA-nSCC-HN pts were enrolled. All R-SCC-HN pts had prior radiotherapy with a dose of 65.5Gy (range, 59.4–76.0). The tumor minimum dose was 31.0Gy-Eq (range, 16.1–42.6). ORR for all pts were 71.4%, and CR/PR were 50.0%/25.0% in R-SCC-HN and 7.7%/61.5% in R/LA-nSCC-HN. With a median follow up of 21.3 months (range 9.2–30.6), 1-year PFS by investigator review were 70.6%. Other ecacy data are shown in the table. For adverse event, nausea (81%), dysgeusia (71%), acute parotitis (67%) were observed frequently.Table: 1135PTable: 1135PAll (N=21)R-SCC-HN (N=8)R/LA-nSCC-HN (N=13)Overall response rate, n (%) (95% CI)15 (71.4) (47.8–88.8)6 (75) (34.9–96.8)9 (69.2) (38.6–90.9)Disease control rate, n (%) (95% CI)20 (95.2) (76.2–99.9)7 (87.5) (47.3–99.7)13 (100) (79.4–100)Median progression-free survival, monthsNR10.4NR1-y / 2-y progression-free survival rate, %70.6 / 65.530.0 / 15.092.3 / 92.31-y / 2-y overall survival rate, %94.7 / 85.383.3 / 55.6100 / 100NR, Not reached. ConclusionsThese data suggest that AB-BNCT with borofalan(10B) emerges as a promising treatment option for pts with R –SCC- HN or R/LA-nSCC-HN with no other treatment option. Clinical trial identificationJapicCTI-194640. Legal entity responsible for the studySumitomo Heavy Industries, Ltd, Stella Pharma Corporation. FundingFukushima prefectural subsidy for development and testing of global cutting-edge medical devices. DisclosureK. Hirose: Research grant / Funding (self), Travel / Accommodation / Expenses: Sumitomo Heavy Industries, Ltd; Travel / Accommodation / Expenses: Stella Pharma Corporation. K. Ono: Advisory / Consultancy: Stella Pharma Corporation; Advisory / Consultancy: Sumitomo Heavy Industries, Ltd. Y. Takai: Travel / Accommodation / Expenses: Stella Pharma Corporation; Travel / Accommodation / Expenses: Sumitomo Heavy Industries, Ltd. All other authors have declared no conflicts of interest.

CYTOPATHIC EFFECTS OF ACCELERATOR-BASED BORON NEUTRON CAPTURE THERAPY ON HUMAN GLIOBLASTOMA CELLS

Boron neutron capture therapy (BNCT) is a targeted therapy based on a selective damage to cancer cells due to the interaction between boron-10 isotope and neutron. Reactor-based BNCT has been found to be effective in the treatment of high-grade gliomas. It is believed that compact accelerator-based neutron sources will ensure widespread adoption of the technique in clinical practice. New accelerator-based neutron sources are being actively developed all over the world. At the Institute of Nuclear Physics (Russia), the accelerator-based neutron source was developed for pre-clinical studies of BNCT.Purpose: to determine the cytopathic effects of accelerator-based BNCT on the human U87-glioblastoma cell line and to select a concentration of boron drugs that do not have a toxic effect on the cells before irradiation in vitro.Material and Methods. To assess the cytopathic effects (MTT test and colony-forming assay) of various concentrations of boron-containing drugs, U87 cells were incubated with boronophenylalanine (BPA) and sodium borocaptate (BSH) for 1, 2 and 10 days. The effect of BNCT on the U87 cell line was determined using colony-forming assay.Results. The MTT test showed a decrease in cell survival at a boron-10 isotope concentration of 160 μg/ml after 48 hours and 640 μg/ml after 24 hours of incubation for BPA. The cytopathic effects for sodium BSH appeared at a boron concentration of 80 µg / ml after 48 hours of incubation, and survival fraction of cells was reduced to 89 % compared to the control. According to the colonyforming assay, the cytotoxic effects of BSH and BPA at a boron concentration of 40 µg/ml in the medium were 79.6 and 84 %, respectively. The proportions of surviving cells were 18 ± 2 % and 13 ± 2 % after epithermal neutron irradiation in the presence of boronophenylalanine and in the presence of sodium borocaptate, respectively. Cell death without boron drugs occurred due to the neutron elastic scattering, nuclear reactions of thermal neutron capture by hydrogen and nitrogen, and accompanying gamma radiation.Conclusion. The study clearly showed a decrease in the proportion of surviving U87 cells after accelerator-based BNCT in the presence of 10B-enriched BSH and BPA.

A Prospective Phase 2 Trial of Accelerator-Based Boron Neutron Capture Therapy for Recurrent and Locally Advanced Head and Neck Cancer: Initial Report of Treatment Outcome

A Prospective Phase 2 Trial of Accelerator-Based Boron Neutron Capture Therapy for Recurrent and Locally Advanced Head and Neck Cancer: Initial Report of Treatment Outcome

The Kinetic Behaviors of H Impurities in the Li/Ta Bilayer: Application for the Accelerator-Based BNCT.

Hydrogen bubble phenomenon is one of the key issues to be solved in the development of a long-life target system for boron neutron capture therapy (BNCT). In this study, we assessed the kinetic behaviors of H impurities in the nano-composite target from the atomic level. Firstly, two kinds of Li/Ta nanolayer models were constructed, based on the calculated lattice parameters and surface energies. The H solution energy, diffusion mechanism, and hydrogen bubbles formation in the Li/Ta nanostructured bilayer were studied, through theoretical modeling and simulation. Our results show that the Li/Ta interfaces are effective sinks of H atoms because the H solution energies in the interface are lower. Meanwhile, due to the relatively low diffusion barriers, the large-scale H transport through the interface is possible. In addition, although it is more likely to form hydrogen bubbles in the Ta layer, compared with the Li layer, the anti-blistering ability of Ta is more impressive compared with most of other candidate materials. Therefore, the Ta layer is able to act as the hydrogen absorber in the Li/Ta bilayer, and relieve the hydrogen damage of the Li layer in the large-scale proton radiations.

Experimental study of fast-neutron production and moderation for accelerator-based BNCT system

This work aims to study the fast-neutron production and moderation for the development of a compact accelerator-based multi-port Boron Neutron Capture Therapy (AB-mBNCT) system. An initial energy distribution and the efficiency of a test moderator assembly (TMA) for fast neutrons from a tungsten (W) target bombarded with a 53 MeV proton beam were measured using organic scintillators. The experimental results were reproduced with reasonable accuracy by simulations using the PHITS code. This paper will discuss about the experimental outcome and the related benchmark calculations by PHITS code.