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| Author | : Xiao-Lin Zhou |
| Publisher | : |
| Total Pages | : 422 |
| Release | : 1990 |
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| Author | : Rajat Kudchadker |
| Publisher | : |
| Total Pages | : 418 |
| Release | : 1996 |
| Genre | : Boron-neutron capture therapy |
| ISBN | : |
Boron Neutron capture therapy (BNCT) is a form of radiation therapy in which nuclides having a high tendency for capturing thermal neutrons, react by emitting charged particles of short range and leaving essentially no residual radioactivity. If these capture nuclides are selectively introduced into the tumor cells, it is theoretically possible to destroy only the tumor and in the process spare the neighboring healthy tissue. Currently, reactors are the only known source of neutrons being used for BNCT. A number of studies have been done using Monte Carlo computer codes such as MCNP to determine an optimum design of a moderator reflector configuration for an accelerator based neutron source utilizing the Li-7(p, n)Be-7 reaction. To confirm this, benchmark experiments were conducted using both a 2.0 MeV Radio Frequency Quadrupole (RFQ) accelerator and a 2.0 MeV Van de Graaff generator. All previous studies had concluded that 2.5 MeV protons would be optimum, which produces neutron having a maximum energy of 787 keV. For BNCT the desired neutron energies are between 1 eV and nominally 10 keV, i.e. in the epithermal region. These neutrons must hence be moderated to bring them down to the desired energy range. The moderator-reflector assemblies for reactor neutrons or those from 2.5 MeV protons on lithium require a little less than a meter of material to achieve the desired neutron spectrum. This research work focuses on using protons with energies just above the Li-7(p, n)Be-7 reaction threshold. These lower energy protons produce neutrons with a maximum energy of just a few hundred keV requiring much less moderation as compared to the 2.5 MeV proton lithium source. The penalty for the low energy neutron spectrum is the low yield of neutrons per proton as compared to the 2.5 MeV protons on lithium. But, less moderation implies that the patient can be moved closer to the lithium target (neutron source), thus making a more efficient use of the source neutrons. This would partially or wholly compensate for the lower yield per proton. In addition the smaller moderator-reflector assembly would result in less scattering occurring, thereby not degrading the forward directional quality of the beam as much as in current assemblies designed for use with the 2.5 MeV protons on a lithium target.
| Author | : M. Frederick Hawthorne |
| Publisher | : Springer |
| Total Pages | : 1389 |
| Release | : 2013-11-11 |
| Genre | : Medical |
| ISBN | : 1461512859 |
Frontiers in Neutron Capture Therapy contains current research results originally presented at the Eighth International Symposium on Neutron Capture Therapy for Cancer in La Jolla, CA. This comprehensive collection of peer-reviewed manuscripts is showcased in two volumes covering all aspects of the development of this multidisciplinary approach to cancer therapy. Volume I of this work includes clinical results and current progress in treatment planning, neutron sources and dosimetry, while Volume II presents the synthesis, pharmacology and tissue-targeting design of boron compounds, including work on preclinical dosimetry and radiobiology. Intended for researchers and clinicians involved with or interested in new modes of cancer therapy, this volume will also serve as a useful guideline for scientists, students, and practitioners in the field.
| Author | : Charles Leon Lee |
| Publisher | : |
| Total Pages | : 219 |
| Release | : 1998 |
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| Author | : Otto K. Harling |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 340 |
| Release | : 2013-03-08 |
| Genre | : Medical |
| ISBN | : 1468458027 |
For this Workshop, the organizers have attempted to invite experts from all known centers which are engaged in neutron beam development for neutron capture therapy. The Workshop was designed around a series of nineteen invited papers which dealt with neutron source design and development and beam characterization and performance. Emphasis was placed on epithermal beams because they offer clinical advantages and are more challenging to implement than thermal beams. Fission reactor sources were the basis for the majority of the papers; however three papers dealt with accelerator neutron sources. An additional three invited papers provided a summary of clinical results of Ncr therapy in Japan between 1968 and 1989 and overviews of clinical considerations for neutron capture therapy and of the status of tumor targeting chemical agents for Ncr. Five contributed poster papers dealing with NCT beam design and performance were also presented. A rapporteurs' paper was prepared after the Workshop to attempt to summarize the major aspects, issues, and conclusions which resulted from this Workshop. Many people contributed to both the smooth functioning of the Workshop and to the preparation of these proceedings. Special thanks are reserved for Ms. Dorothy K.
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| Total Pages | : 278 |
| Release | : 1996 |
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Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 107 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF3 composite and a stacked Al/Teflon design) at various incident electron energies.
| Author | : Takahiro Kato |
| Publisher | : |
| Total Pages | : |
| Release | : 2017 |
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Purpose; To describe the 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 (STBRC).Materials and Methods; AB-BNCT system at the STBRC is equipped with a cyclotron-based epithermal neutron source (C-BENS), which consists of a cyclotron accelerator (HM-30), a beryllium neutron production target, and a beam shaping assembly (BSA). We developed a remote patient transport system (RPTS) for workers to reduce the work time in the treatment room under the condition of remaining activities just after an irradiation. We studied the feasibility of this system and carefully designed optimum layout to realize patient flow and workflow efficiently.Results; We designed the upside-down Y shaped beamline configuration, in which HM-30 and two treatment rooms are assumed to be located on a top and bottoms, respectively. To reduce the activities caused by thermal neutron, BSA is surrounded by LiF-loaded polyethylene blocks and low-activation concrete. The measured out-of-field thermal and fast neutron dose profiles were in good agreement with calculated ones using MCNPX. It was also confirmed that the RPTS could be operated up to 9 m apart from the RPTS without any problems. Conclusion; We successfully established the environment of BNCT as one of the division of general hospital without sense of incongruity in comparison of environment of conventional radiotherapy. The AB-BNCT system described in this study confirmed to specifications and is being used for BNCT in a hospital.
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| Release | : 2003 |
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The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 107 W/m2 with heat transfer coefficients of 106W/m2-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and compared the RBE characteristics of the MIT Reactor M67 clinical beam, The Brookhaven Medical Research Reactor clinical beam (both of which were used in Phase I/II clinical trials of BNCT) and the MIT LABA BNCS beam. Additional research initiated under this program involved an investigation of the potential of BNCT for the prevention of restenosis and the development of accelerator-based fast neutron brachytherapy. A total of 10 student research theses (2 Undergraduate, 4 Masters, and 4 Doctoral) were completed as part of this research program.
| Author | : Michael John Wilson |
| Publisher | : |
| Total Pages | : 63 |
| Release | : 1991 |
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| Release | : 1989 |
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We present a conceptual design of a low-energy neutron generator for treatment of brain tumors by boron neutron capture theory (BNCT). The concept is based on a 2.5-MeV proton beam from a radio-frequency quadrupole (RFQ) linac, and the neutrons are produced by the 7Li(p, n)7Be reaction. A liquid lithium target and modulator assembly are designed to provide a high flux of epithermal neutrons. The patient is administered a tumor-specific 1°Be-enriched compound and is irradiated by the neutrons to create a highly localized dose from the reaction 1°B(n, .cap alpha.)7Li. An RFQ accelerator-based neutron source for BNCT is compact, which makes it practical to site the facility within a hospital. 11 refs., 5 figs., 1 tab.
