Temperature Volume Histograms for Precise Thermal Ablation Isotherms

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Solution Overview

Problem

Current methods for thermal ablation procedures lack the ability to empirically measure actual tissue temperatures during the procedure, relying instead on imaging to estimate lethal isotherms, which are not fully informative of the desired -20 or -40 degrees Celsius isotherms.

Innovation Solution

A control circuit generates a temperature volume histogram as a function of characterizing information for a thermal ablation apparatus, incorporating empirically-sensed and modeled patient data to predict isothermic distribution and lethality zones, facilitating precise thermal ablation planning and quality assurance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple thermal recorders are inserted in and around the target volume during the procedure to empirically measure tissue temperature, then measurement precision is improved, but device complexity and ease of operation deteriorate

Engineering Contradiction:
Improvetissue temperature measurementVSAvoidmultiple thermal recorders insertion
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the physical measurement system by generating a temperature volume histogram that represents the three-dimensional temperature distribution throughout the target volume. This computational model replicates what multiple physical thermal recorders would measure, but without requiring actual insertion of multiple sensors into the patient's tissue.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical system of inserting multiple physical thermal recorders into tissue with a computational system that calculates temperature distribution based on imaging data and thermal modeling. This substitution eliminates the need for complex physical sensor arrays while providing comprehensive temperature information.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If imaging is used to estimate ice ball size and lethal isotherms during the procedure, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveimaging-based estimationVSAvoidlethal isotherm determination
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transforms the estimation process by changing from visual/image-based assessment to quantitative parameter-based analysis. The temperature volume histogram provides precise numerical data about temperature distribution, allowing accurate determination of lethal isotherms (-20°C and -40°C) through computational analysis rather than visual estimation from imaging.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a computational intermediary (the temperature volume histogram generation system) that bridges the gap between simple imaging data and precise temperature measurement. This intermediary processes imaging data and thermal models to produce accurate temperature distribution information without requiring complex physical measurement systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the ice ball volume is used to represent the treated volume, then ease of operation is improved, but loss of information increases

Engineering Contradiction:
Improveice ball volume assessmentVSAvoidlethal isotherm temperature distribution
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent segments the temperature distribution information into distinct temperature zones within the target volume, creating a detailed histogram that shows how much volume exists at each temperature level. This segmentation reveals the temperature distribution structure within the ice ball, showing which portions reach lethal temperatures for cancer cells versus merely freezing temperatures.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4606331A1Temperature volume histogram generation apparatus and method
Publication Date: 2025.08.27 VARIAN MEDICAL SYSTEMS INC
  • EP4606331A1 patent drawingFigure 1
  • EP4606331A1 patent drawingFigure 2
  • EP4606331A1 patent drawingFigure 3

AI summary

To facilitate administering thermal ablation (such as, but not limited to, cryotherapy) to a patient's target volume, a control circuit can access characterizing information for a particular thermal ablation apparatus and then generate a temperature volume histogram as a function of the characterizing information for that particular thermal ablation apparatus.