DaRT Source Radon Release Control for Tumor Coverage
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Solution Overview
Problem
Current radiotherapy methods using alpha particles face challenges in delivering sufficient radiation to tumors while minimizing damage to healthy tissues, due to the short range of alpha particles and limited deployment methods, which can lead to incomplete tumor destruction and potential harm to distant organs.
Innovation Solution
The development of diffusing alpha-emitter radiation therapy (DaRT) sources with tailored radon release rates and spacings to ensure effective tumor coverage, using radium-223 or radium-224 atoms that diffuse and decay to release alpha-emitting radon daughters, allowing for controlled and targeted radiation delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher activity sources are used to ensure sufficient radiation delivery to the tumor, then tumor destruction effectiveness is improved, but the risk of damaging distant healthy organs increases due to radon clearance through blood
Solution Approach 1:
The patent applies parameter changes by precisely controlling the activity level of DaRT sources and optimizing radon release rates to achieve the desired balance between tumor destruction and healthy tissue protection. Specific activity ranges and radon release rates are established to ensure effective treatment while minimizing systemic radiation exposure.
2Object-affected harmful factors
If the short range of alpha particles is utilized to spare healthy tissue, then damage to surrounding healthy tissue is reduced, but insufficient radiation coverage of the entire tumor volume occurs
Solution Approach 1:
The patent uses radon gas as an intermediary carrier that transports alpha-emitting radium atoms throughout the tumor volume. The radon atoms diffuse from the implanted DaRT sources and deliver radiation to distant tumor cells while the short range of alpha particles ensures healthy tissue beyond the tumor remains protected. This intermediary mechanism resolves the contradiction between localized damage and comprehensive coverage.
3Reliability
If more radon atoms are released to increase tumor destruction probability, then tumor treatment effectiveness is improved, but clearance of radon daughters through blood to distant organs increases
Solution Approach 1:
The patent optimizes the radon release rate parameter to achieve the desired balance. By controlling the activity of DaRT sources and the radon release characteristics, the system delivers sufficient radiation to destroy tumor cells while limiting the amount of radon that can be cleared through the bloodstream to distant organs.
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 approach enables precise and effective tumor treatment by optimizing radon release rates and source spacing to achieve desired radiation doses, minimizing exposure to healthy tissues and enhancing treatment efficacy across various tumor types.
Implementation Method 1
radium-223 or radium-224 atoms, which generate chains of several radioactive decays with a governing half-life of 3.6 days for radium-224 and 11.4 days for radium-223
Implementation Method 2
These radionuclides, and their own radioactive daughter atoms, spread around the source by diffusion up to a radial distance of a few millimeters before they decay by alpha emission
Implementation Method 3
Alpha particles are a powerful means for radiotherapy since they induce clustered double-strand breaks on the DNA, which cells cannot repair
Data Source
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AI summary
A diffusing alpha-emitter radiation therapy (DaRT) source for use in treatment of a cancer tumor of a patient, the source comprising a support having a length of at least 1 millimeter; and radium-224 atoms coupled to the support such that not more than 20% of the radium-224 atoms leave the support into the tumor in 24 hours, without decay, when the source is implanted in the tumor, but upon decay, at least 5% of daughter radionuclides of the radium-224 atoms leave the support upon decay. The administration pattern of the source comprises implanting the source in the cancer tumor throughout the tumor, with a spacing between the sources of between 3 - 4.5 millimeters, and the radiation therapy source has a radon release rate of between 1.2 and 2.0 microcurie per centimeter length.