An Experimental Study of the Moderator Assembly for a Low-Energy Proton Accelerator Neutron Irradiation Facility for BNCT

Wang, C. K.; Blue, Thomas E.; Blue, J. W.

doi:10.1007/978-1-4684-5802-2_21

Cited by 7 publications

(2 citation statements)

References 4 publications

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“…In this study, the energy spectrum is derived from the neutron source project at Lanzhou University, 32 as shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

Primary study of the relative and compound biological effectiveness model for boron neutron capture therapy based on nanodosimetry

Mao,

Zhang,

Luo

et al. 2024

Medical Physics

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BackgroundThe current radiobiological model employed for boron neutron capture therapy (BNCT) treatment planning, which relies on microdosimetry, fails to provide an accurate representation the biological effects of BNCT. The precision in calculating the relative biological effectiveness (RBE) and compound biological effectiveness (CBE) plays a pivotal role in determining the therapeutic efficacy of BNCT. Therefore, this study focuses on how to improve the accuracy of the biological effects of BNCT.PurposeThe purpose of this study is to propose new radiation biology models based on nanodosimetry to accurately assess RBE and CBE for BNCT.MethodsNanodosimetry, rooted in ionization cluster size distributions (ICSD), introduces a novel approach to characterize radiation quality by effectively delineating RBE through the ion track structure at the nanoscale. In the context of prior research, this study presents a computational model for the nanoscale assessment of RBE and CBE. We establish a simplified model of DNA chromatin fiber using the Monte Carlo code TOPAS‐nBio to evaluate the applicability of ICSD to BNCT and compute nanodosimetric parameters.ResultsOur investigation reveals that both homogeneous and heterogeneous nanodosimetric parameters, as well as the corresponding biological model coefficients α and β, along with RBE values, exhibit variations in response to varying intracellular 10B concentrations. Notably, the nanodosimetric parameter effectively captures the fluctuations in model coefficients α and RBE.ConclusionOur model facilitates a nanoscale analysis of BNCT, enabling predictions of nanodosimetric quantities for secondary ions as well as RBE, CBE, and other essential biological metrics related to the distribution of boron. This contribution significantly enhances the precision of RBE calculations and holds substantial promise for future applications in treatment planning.

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“…In this study, the energy spectrum is derived from the neutron source project at Lanzhou University, 32 as shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

Primary study of the relative and compound biological effectiveness model for boron neutron capture therapy based on nanodosimetry

Mao,

Zhang,

Luo

et al. 2024

Medical Physics

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“…A Monte Carlo ͑MC͒ method has been widely used to design radiotherapy beams because of its accuracy and efficiency in estimating the performance of various designs under consideration. Many papers were published to demonstrate the potential and successful applications for the design of photon beams, 11,17,20,21,26 neutron beams, [12][13][14][15]19,23,25 and electron beams. 16,18,22,24,27,28 However, Monte Carlo applications for the design of TSEI beams have been limited primarily because they involve large-scale simulations in timeconsuming electron transport.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo techniques for scattering foil design and dosimetry in total skin electron irradiations

Pareek

Spencer

et al. 2005

Medical Physics

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Total skin electron irradiation (TSEI) with single fields requires large electron beams having good dose uniformity, dmax at the skin surface, and low bremsstrahlung contamination. To satisfy these requirements, energy degraders and scattering foils have to be specially designed for the given accelerator and treatment room. We used Monte Carlo (MC) techniques based on EGS4 user codes (BEAM, DOSXYZ, and DOSRZ) as a guide in the beam modifier design of our TSEI system. The dosimetric characteristics at the treatment distance of 382 cm source-to-surface distance (SSD) were verified experimentally using a linear array of 47 ion chambers, a parallel plate chamber, and radiochromic film. By matching MC simulations to standard beam measurements at 100 cm SSD, the parameters of the electron beam incident on the vacuum window were determined. Best match was achieved assuming that electrons were monoenergetic at 6.72 MeV, parallel, and distributed in a circular pattern having a Gaussian radial distribution with full width at half maximum = 0.13 cm. These parameters were then used to simulate our TSEI unit with various scattering foils. Two of the foils were fabricated and experimentally evaluated by measuring off-axis dose uniformity and depth doses. A scattering foil, consisting of a 12 x 12 cm2 aluminum plate of 0.6 cm thickness and placed at isocenter perpendicular to the beam direction, was considered optimal. It produced a beam that was flat within +/-3% up to 60 cm off-axis distance, dropped by not more than 8% at a distance of 90 cm, and had an x-ray contamination of <3%. For stationary beams, MC-computed dmax, Rp, and R50 agreed with measurements within 0.5 mm. The MC-predicted surface dose of the rotating phantom was 41% of the dose rate at dmax of the stationary phantom, whereas our calculations based on a semiempirical formula in the literature yielded a drop to 42%. The MC simulations provided the guideline of beam modifier design for TSEI and estimated the dosimetric performance for stationary and rotational irradiations.

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Boron neutron capture therapy for cancer. Realities and prospects

Barfh

Soloway

Fairchild

et al. 1992

Cancer

270

104

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Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when a stable isotope, boron‐10 (10B), is irradiated with low‐energy thermal neutrons (nth) to yield (4He) α‐particles and 7Li nuclei (10B + nth→ [11B] → 4He + 7Li + 2.31 MeV). The success of BNCT as a tumoricidal modality is dependent on the delivery of a sufficient quantity of 10B and nth to individual cancer cells to sustain a lethal 10B(n, α) 7Li reaction. The current review covered the radiobiologic considerations on which BNCT is based, including a brief discussion of microdosimetry and normal tissue tolerance. The development of tumor‐localizing boron compounds was discussed, including the sulfhydryl‐containing polyhedral borane, sodium borocaptate (Na2 B12 H11 SH), and borono‐phenylalanine [BPA], both of which are currently being used clinically in Japan as capture agents for malignant brain tumors and melanomas, respectively. Compounds currently under evaluation, such as boronated porphy‐rins, nucleosides, liposomes, and monoclonal antibodies (MoAbs), were also considered. Nuclear reactors have been used as the exclusive source of neutrons for BNCT. The use of low‐energy (0.025 eV) thermal neutrons and higher‐energy 1–10, 000 eV) epithermal beams, beam optimization, and possible alternative neutron sources (accelerators) were also discussed. Clinical studies performed in the United States during the 1950s and 1960s for the treatment of malignant brain tumors were reviewed. Current studies in Japan and future studies in Europe and the United States concerning the treatment of glioblastomas and melanomas by BNCT were discussed, as were critical issues that must be addressed if BNCT is ever to be a useful therapeutic modality.

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An Experimental Study of the Moderator Assembly for a Low-Energy Proton Accelerator Neutron Irradiation Facility for BNCT

Cited by 7 publications

References 4 publications

Primary study of the relative and compound biological effectiveness model for boron neutron capture therapy based on nanodosimetry

Primary study of the relative and compound biological effectiveness model for boron neutron capture therapy based on nanodosimetry

Monte Carlo techniques for scattering foil design and dosimetry in total skin electron irradiations

Boron neutron capture therapy for cancer. Realities and prospects

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