Pulsed Laser Resonator for Tissue Coagulation Without Vaporization
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Solution Overview
Problem
During medical treatments involving laser tissue ablation, incomplete coagulation of neighboring tissue can lead to bleeding, as existing methods may not consistently achieve coagulation without vaporizing additional tissue.
Innovation Solution
A medical laser system that emits windows of pulses of laser light at spaced time intervals, with each window containing a plurality of pulses, is used to heat tissue to a temperature causing coagulation without vaporization. The system includes a pump module, a resonator with a gain medium and reflective surfaces, and a controller that adjusts the light attenuation to achieve the desired pulse patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a lower intensity laser light is applied to induce coagulation, then bleeding is reduced, but the coagulation may be incomplete and additional bleeding occurs
Solution Approach 1:
The patent applies periodic pulsed laser action with specific duty cycles (e.g., 10-90% duty cycle) to deliver controlled bursts of high intensity laser energy followed by intervals. This periodic delivery allows cumulative heating of tissue to achieve complete coagulation while preventing vaporization, resolving the contradiction between sufficient coagulation and avoiding incomplete treatment
Solution Approach 2:
The patent changes key parameters including pulse duration (microsecond to millisecond range), repetition rate (e.g., 1-100 Hz), and duty cycle to optimize the balance between coagulation effectiveness and vaporization prevention. By adjusting these parameters, the system achieves reliable complete coagulation without the harmful effects of continuous high intensity exposure
2Reliability
If higher intensity laser light is used to ensure complete coagulation, then coagulation reliability improves, but tissue vaporization occurs
Solution Approach 1:
The pulsed laser delivery with controlled duty cycles (10-90%) provides high intensity energy bursts for complete coagulation while interspersing cooling intervals that prevent cumulative overheating and vaporization. The periodic on-off pattern allows the tissue to absorb sufficient energy for coagulation without reaching vaporization temperatures
Solution Approach 2:
The system dynamically adjusts pulse duration, repetition rate, and duty cycle based on treatment requirements to optimize the balance between coagulation effectiveness and vaporization prevention. This dynamic parameter control allows the same system to adapt to different tissue types and treatment depths
3Temperature
If continuous laser light is applied to heat tissue, then heating efficiency improves, but temperature control becomes difficult and vaporization occurs
Solution Approach 1:
The pulsed laser delivery replaces continuous exposure with controlled periodic bursts, maintaining high heating efficiency during pulse periods while the off-periods allow temperature stabilization and prevent runaway heating. This periodic approach provides inherent temperature control by limiting cumulative energy deposition
Solution Approach 2:
The system incorporates feedback mechanisms including temperature sensing and real-time adjustment of pulse parameters (duration, repetition rate, duty cycle) to maintain optimal tissue temperature for coagulation. This feedback control prevents temperature excursions that would lead to vaporization while ensuring complete coagulation
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 system effectively coagulates tissue without vaporization, reducing bleeding and improving the precision of medical laser treatments by controlling the intensity and timing of laser pulses.
Implementation Method 1
a gain medium receiving pump energy from the pump module and producing light
Implementation Method 2
reflective surfaces reflecting light produced by the gain medium back toward the gain medium
Implementation Method 3
a variable light attenuator receiving light produced by the gain medium
Implementation Method 4
The emitted windows of pulses of laser light heat tissue to a temperature that causes coagulation without vaporization
Data Source
AI summary
A laser resonator includes a gain medium that produces light from pump energy and a variable light attenuator, which receives light and emits either (i) a first light including a continuous series of micropulses, or (ii) a second light including a series of macropulses at spaced time intervals, where each macropulse includes a series of micropulses. Each micropulse has a duration of 0.1 to 10 microseconds, and a duration of each macropulse is less than the time interval between each macropulse, and the micropulses have a frequency of 5 kHz to 40 kHz.