DaRT Source Spacing and Radon Release for Prostate Tumor Coverage

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Solution Overview

Problem

Existing radiotherapy methods using alpha particles struggle to effectively deliver sufficient radiation to tumor volumes while minimizing damage to healthy tissue, due to the short range of alpha particles and lack of practical methods to deploy alpha-emitting atoms uniformly throughout the tumor.

Innovation Solution

The use of diffusing alpha-emitter radiation therapy (DaRT) sources with tailored radon release rates and spacings, such as 1.5 to 3.2 microcurie per centimeter length and 3 to 4 millimeters spacing, to ensure adequate radiation coverage and minimize healthy tissue exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If alpha particles are used for radiotherapy, then tumor cell destruction is enhanced, but the short range limits the treatment to small tumor volumes

Engineering Contradiction:

Improvetumor cell destruction effectivenessVSAvoidtumor volume treatability

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The treatment divides the tumor into multiple zones by implanting multiple DaRT sources at different locations. Each source creates a localized radiation zone through diffusion, and the combined effect of multiple segmented zones achieves comprehensive coverage of the entire tumor volume, overcoming the limited range of individual alpha particles.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces radon atoms as intermediary carriers that diffuse from the radium-224 source into the tumor tissue. These radon atoms act as mobile mediators that transport alpha-emitting capability throughout the tumor volume, extending the effective treatment range beyond the physical range of direct alpha particles from the source.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If radium-224 sources with high activity are implanted, then sufficient radiation dose is delivered to destroy tumor, but healthy tissue outside tumor receives excessive radiation

Engineering Contradiction:

Improvetumor destruction probabilityVSAvoiddamage to healthy tissue

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the local radiation characteristics by controlling the radon release rate (1.5-3.2 μCi/cm) and source spacing (3-4 mm) to create concentrated radiation zones. This localized quality control ensures high radiation dose to tumor while minimizing spillage into surrounding healthy tissue, achieving selective tumor destruction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent carefully adjusts critical parameters including radium activity (1.5-3.2 μCi/cm), radon release rate, source spacing (3-4 mm), and treatment duration to optimize the balance between tumor destruction and healthy tissue protection. These parameter optimizations ensure sufficient tumor dose while keeping healthy tissue exposure within safe limits.

Inventive Principle:

Principle #35Parameter changes

3Area of stationary object

If DaRT sources are placed close together, then complete tumor coverage is achieved, but the complexity of source placement increases

Engineering Contradiction:

Improvetumor coverage areaVSAvoidsource placement complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent specifies a standardized source spacing of 3-4 mm that provides sufficient tumor coverage without requiring overly complex placement. This partial action approach uses a simple, repeatable spacing rule that achieves complete coverage while maintaining operational simplicity and reducing placement complexity.

Inventive Principle:

Principle #16Partial or excessive action

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 provides targeted and effective tumor treatment with reduced risk to healthy tissue by optimizing radon release rates and source placement, ensuring complete tumor destruction or size reduction while adhering to safety limits.

Implementation Method 1

radium-224 atoms, which generate chains of several radioactive decays with a governing half-life of 3.6 days for radium-224

Methodology Applied

Scientific EffectRadioactive decay: Radioactive Decay

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

Methodology Applied

Scientific EffectDiffusion: Diffusion

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

Methodology Applied

Scientific EffectAlpha particle radiation: Radiation

Data Source

PatentUS20260000912A1Diffusing alpha-emitter radiation therapy for prostate cancer

Publication Date: 2026.01.01 ALPHA TAU MEDICAL LTD

AI summary

A method for treating a tumor, comprising identifying a tumor as a prostate cancer tumor and implanting in the tumor identified as a prostate cancer tumor, at least one diffusing alpha-emitter radiation therapy (DaRT) source with a radon release rate between 1.8 and 2.2 microcurie, per centimeter length.