Histotripsy Thermal Dose Planning with Depth-Based Cooling Periods
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Solution Overview
Problem
Existing Histotripsy treatments require cooling periods to prevent tissue damage due to high driving voltages, especially at greater treatment depths, necessitating a method for determining and implementing cooling periods based on varying depths and voltages.
Innovation Solution
A method and system for determining and implementing cooling time periods in a digital treatment plan, which vary based on treatment depth and driving voltage, with non-uniform distribution throughout the target tissue volume, and a robotic positioning system to deliver histotripsy therapy according to the plan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If higher driving voltages are emitted from a transducer to treat deeper tissue locations, then treatment depth is improved, but thermal damage risk increases requiring cooling periods
Solution Approach 1:
The system performs preliminary calculations of thermal dose before treatment begins, using the calculated thermal profiles to pre-determine appropriate cooling periods. This preliminary thermal dosimetry allows the system to plan the entire treatment sequence with cooling intervals built in, preventing thermal damage before it occurs while maintaining deep tissue treatment capability
Solution Approach 2:
The treatment protocol implements periodic cooling intervals between ultrasound pulses, creating a cyclic pattern of treatment and cooling. This periodic action allows thermal energy to dissipate during off-periods while delivering therapeutic effect during active periods, enabling deep tissue treatment without cumulative thermal damage
2Object-affected harmful factors
If cooling periods are added to prevent thermal damage, then tissue safety is improved, but treatment time increases
Solution Approach 1:
The cooling period durations are dynamically adjusted based on real-time calculations of thermal dose and tissue depth. Rather than using fixed cooling intervals, the system varies cooling durations to match the specific thermal accumulation rate at each treatment location, optimizing the balance between safety and efficiency for each unique treatment scenario
Solution Approach 2:
The system changes thermal management parameters (cooling period duration, pulse repetition frequency) based on treatment depth and tissue characteristics. By adapting these parameters dynamically rather than maintaining constant values, the system minimizes total treatment time while ensuring thermal safety margins are maintained throughout the procedure
3Device complexity
If uniform cooling periods are applied throughout the treatment volume, then thermal management is simplified, but treatment precision at varying depths deteriorates
Solution Approach 1:
The system applies different cooling period durations to different regions of the treatment volume based on local thermal accumulation characteristics. Deeper regions receiving higher energy doses get longer cooling intervals, while shallower regions get shorter intervals. This localized thermal management ensures precise thermal control throughout the heterogeneous treatment volume
Solution Approach 2:
The treatment volume is segmented into multiple regions with different thermal management requirements. Each segment is assigned appropriate cooling parameters based on its depth and energy absorption characteristics, allowing precise thermal control without requiring a single complex unified protocol
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
Enables precise and controlled tissue treatment by managing thermal profiles, preventing tissue damage and ensuring effective delivery of histotripsy therapy across varying tissue depths and voltages.
Implementation Method 1
Histotripsy, or pulsed ultrasound cavitation therapy, is a technology where extremely short, intense bursts of acoustic energy induce controlled cavitation (microbubble formation) within the focal volume
Implementation Method 2
The vigorous expansion and collapse of these microbubbles mechanically homogenizes cells and tissue structures within the focal volume
Implementation Method 3
treating a target volume of tissue with a transducer or other device with devices in Histotripsy procedure necessitates cooling periods (i.e. periods of no treatment) to prevent damage and overheating of tissues
Data Source
AI summary
A histotripsy therapy system configured for the treatment of tissue is provided, which may include any number of features such as planning and implementation of an adaptive distribution of cooling periods across a treatment volume of tissue given various treatment depths and voltages. Provided herein are systems and methods that provide efficacious non-invasive and minimally invasive therapeutic, diagnostic and research procedures for tissue cooling. Other embodiments are described herein.