Tailored Laser Pulse Shaping for Stone Fragmentation Control
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Solution Overview
Problem
Conventional laser systems for medical procedures like lithotripsy face inefficiencies in stone fragmentation, leading to large fragments and undesirable retropulsion effects due to high energy usage, which complicates the extraction process and can cause damage to the laser system.
Innovation Solution
A laser system that employs a controller to direct temporally spaced-apart electrical pulses to a lasing medium, producing a quasi-continuous laser pulse with adjustable duration, power, and frequency, optimizing energy delivery to increase fragmentation efficiency while minimizing retropulsion by reducing the initial peak energy and extending the pulse duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high energy laser is used to increase fragmentation efficiency, then stone fragmentation speed is improved, but stone fragment size increases and retropulsion effects occur
Solution Approach 1:
The laser pulse is segmented into multiple sub-pulses within a single pulse duration, creating a multi-peaked pulse profile. This segmentation allows the energy to be delivered in controlled increments rather than a single high-energy burst, improving fragmentation efficiency while maintaining precise control over fragment size and reducing retropulsion effects.
Solution Approach 2:
The laser pulse profile is made dynamic by introducing temporal variations in energy delivery through multiple sub-pulses with different amplitudes and durations. This dynamic pulse structure adapts the energy delivery pattern to optimize fragmentation while controlling fragment characteristics, transitioning from a static single-peaked pulse to a flexible multi-peaked waveform.
2Productivity
If high energy laser is used to increase fragmentation efficiency, then stone fragmentation speed is improved, but retropulsion effects occur
Solution Approach 1:
The laser pulse is segmented into multiple sub-pulses within a single pulse duration, creating a multi-peaked pulse profile. This segmentation allows the energy to be delivered in controlled increments rather than a single high-energy burst, improving fragmentation efficiency while maintaining precise control over fragment size and reducing retropulsion effects.
Solution Approach 2:
Instead of delivering the full energy in a single peak, the pulse delivers energy in multiple partial peaks that collectively achieve the required fragmentation. This partial action approach prevents excessive energy concentration that causes retropulsion, while the cumulative effect of multiple sub-pulses achieves complete stone fragmentation.
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
The quasi-continuous laser pulse effectively fragments stones with reduced retropulsion and increased efficiency, allowing for more controlled ablation and smaller fragment sizes, enhancing the medical procedure's effectiveness and safety.
Implementation Method 1
a lasing medium configured to output a quasi-continuous laser pulse in response to the optical pumping
Implementation Method 2
a first electrical pulse configured to excite the lasing medium to an energy level below a lasing threshold of the lasing medium
Implementation Method 3
energy of this wavelength is highly absorbed by water, a constituent of virtually all tissues
Data Source
AI summary
A laser system may include a controller configured to direct a plurality of temporally spaced-apart electrical pulses to a device that optically pumps a lasing medium, and a lasing medium configured to output a quasi-continuous laser pulse in response to the optical pumping. The plurality of temporally spaced-apart electrical pulses may include (a) a first electrical pulse configured to excite the lasing medium to an energy level below a lasing threshold of the lasing medium, and (b) multiple second electrical pulses following the first electrical pulse. The quasi-continuous laser pulse is output in response to the multiple second electrical pulses.