Conical Beam-Shaping Apparatus for Focused Neutron Delivery
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Solution Overview
Problem
Current neutron generators for Boron Neutron Cancer Therapy (BNCT) face challenges in producing a focused beam of thermal neutrons for effective tumor treatment, as they often result in isotropic emission, contamination with gamma and higher energy neutrons, and reduced thermal neutron flux, making it difficult to achieve directional, high-density neutron delivery to tumor sites.
Innovation Solution
A modular, compact Low Voltage Fusion neutron generator (LVFG) integrated with a beam-shaping apparatus (BSA) featuring a conically shaped funnel and materials like bismuth and sapphire, which collimates thermal neutrons to create a focused beam suitable for tumor irradiation, minimizing unwanted radiation components and enhancing neutron flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional neutron generators are used for BNCT, then neutron production is achieved, but the emission is isotropic and not directional, making it difficult to focus the beam on tumor sites
Solution Approach 1:
A beam shaping apparatus (BSA) consisting of a moderator block and a conical funnel is introduced as an intermediary component between the neutron source and the tumor site. The moderator block converts fast neutrons to thermal neutrons, while the conical funnel collimates and directs the thermal neutrons into a focused beam, transforming the isotropic emission into a directional beam suitable for precise tumor treatment.
2Manufacturing precision
If a moderator is used to shape neutron energy spectrum, then thermal neutrons are produced suitable for BNCT, but gamma and higher energy neutrons contaminate the beam
Solution Approach 1:
Harmful gamma radiation and high-energy neutrons are extracted and removed from the neutron beam through selective filtering. The conical funnel design and specific moderator materials are chosen to allow thermal neutrons to pass through while blocking or absorbing gamma rays and epithermal neutrons, thereby purifying the beam and leaving only the beneficial thermal neutrons for tumor treatment.
3Manufacturing precision
If neutrons are moderated to thermal energies, then the desired thermal neutron flux is achieved, but the flux density is reduced
Solution Approach 1:
The conical funnel geometry transforms the spatial distribution of thermal neutrons by concentrating them from a larger cross-sectional area at the moderator block into a smaller aperture at the funnel exit. This dimensional transformation increases the flux density at the tumor site while maintaining the overall thermal neutron energy characteristics, effectively resolving the trade-off between thermalization and flux density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables precise delivery of thermal neutrons to tumor sites, improving treatment efficacy by increasing neutron flux and reducing damage to healthy tissues, while allowing for easier positioning and minimization of harmful radiation exposure.
Implementation Method 1
the neutrons created in a reactor or accelerator pass through a moderator, which shapes the neutron energy spectrum suitable for BNCT treatment. While passing through the moderator and then the tissue of the patient, the neutrons are slowed by collisions and become low energy thermal neutrons.
Implementation Method 2
A modular, compact Low Voltage Fusion neutron generator (LVFG) integrated with a beam-shaping apparatus (BSA) featuring a conically shaped funnel and materials like bismuth and sapphire, which collimates thermal neutrons to create a focused beam suitable for tumor irradiation
Implementation Method 3
The thermal neutrons undergo reactions with the boron-10 nuclei at a cancer site, forming compound nuclei (excited boron-11), which then promptly disintegrate to lithium-7 and an alpha particle.
Implementation Method 4
The neutrons interact with the boron to produce fission events whereby alpha particles and lithium nuclei are created.
Implementation Method 5
an elongated beam-shaping apparatus (BSA) having a length and a circular cross section of a diameter less than the length, the BSA joined at one end to and projecting orthogonally from the surface of the moderator block of the neutron source, the BSA having a conically shaped element at an end away from the moderator block
Data Source
AI summary
A cancer treatment apparatus has a neutron source generating neutrons exiting through a surface of a moderator block and an elongated beam-shaping apparatus (BSA) having a length and a circular cross section of a diameter less than the length, the BSA joined at one end to and projecting orthogonally from the surface of the moderator block of the neutron source, the BSA having a conically shaped element at an end away from the moderator block, the conically shaped element declining in diameter in a direction away from the moderator block. Neutrons produced by the neutron source enter the BSA at the surface of the moderator block, travel the length of the BSA, and exit the BSA through an aperture at the end of the BSA away from the moderator block.