Strontium-90 Source with Central Shielding for Uniform Dose
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Solution Overview
Problem
Existing radiological sources used in brachytherapy and medical applications often emit isotropic radiation, exposing surrounding healthy tissues to unnecessary radiation and overexposing tissues at the center of the radiation beam, which is not ideal for targeted treatments like wet age-related macular degeneration.
Innovation Solution
A beta radiological source with increased radioactivity around its periphery and reduced radioactivity at the center, achieved through toroidal or annular shapes, or a minus lens meniscus design, combined with central shielding and attenuating disks made of materials like silver, copper, or tungsten, to concentrate radiation uniformly on diseased tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an isotropic radiological source is used, then radiation is emitted uniformly in all directions, but surrounding healthy tissues are exposed to unnecessary radiation and tissues at the center are overexposed
Solution Approach 1:
The radiological source employs different radioactivity levels in different regions: the peripheral region has higher radioactivity while the central region has lower radioactivity or is shielded. This local differentiation allows the source to deliver uniform radiation dosage to the target tissue while reducing exposure to surrounding healthy tissues.
Solution Approach 2:
The source design breaks the isotropic symmetry by creating an asymmetric radiation distribution pattern through toroidal or annular geometries. This asymmetric configuration concentrates radiation laterally toward the target while minimizing central and posterior exposure to healthy tissues.
2Manufacturing precision
If a toroidal or annular shape with increased peripheral radioactivity is used, then radiation is concentrated uniformly on diseased tissue, but the source structure becomes more complex
Solution Approach 1:
The source utilizes toroidal or annular curved geometries instead of simple spherical or cylindrical shapes. This curvature allows the radioactive material to be distributed in a ring-like structure that naturally concentrates radiation laterally while reducing central exposure, achieving uniform dose distribution through geometric design.
Solution Approach 2:
The invention transitions from a two-dimensional disk or spherical source to a three-dimensional toroidal or annular structure. This dimensional change creates a hollow center region that reduces central radiation exposure while maintaining or enhancing lateral radiation concentration on the target tissue.
3Object-affected harmful factors
If central shielding with denser attenuating materials is added, then radiation from the central portion is substantially attenuated, but the device complexity and material requirements increase
Solution Approach 1:
The invention extracts or removes the central portion of the radioactive source or places a shielding insert in the center. This extraction approach eliminates or reduces the source of central radiation overexposure while preserving the peripheral radioactive material that provides therapeutic benefit to the target tissue.
Solution Approach 2:
A shielding material such as tungsten, gold, or iridium is introduced as an intermediary component between the radioactive source and the target tissue. This intermediary selectively attenuates central radiation while allowing peripheral radiation to reach the target, achieving differential radiation protection.
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
This configuration results in a flat radiation profile, providing a more constant absorbed dose rate throughout the target volume, reducing exposure to healthy tissues and minimizing overexposure at the center of the radiation beam.
Implementation Method 1
providing an encapsulation with increased shielding in the center of the face from which the therapeutic radiation is emitted, thereby substantially attenuating the radiation emitted from the central portion of a source
Implementation Method 2
a beta radiological source, typically containing strontium-90
Data Source
AI summary
The disclosure pertains to a strontium-90 sealed radiological or radioactive source, such as may be used with treatment of the eye or other medical or industrial processes. The sealed radiological source includes a radiological insert within an encapsulation. The encapsulation may include increased shielding in the center thereof.