Visible Laser Pulse Modulation for Retinal Tissue Targeting
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Solution Overview
Problem
Current laser systems for retinal treatments, particularly DPSS lasers, face challenges with unstable performance, high power efficiency, sensitivity to temperature, and limited modulation speed, which can lead to collateral photocoagulation damage and reduced effectiveness in achieving non-thermal therapeutic effects.
Innovation Solution
A visible laser system with adjustable power modulation capabilities, utilizing short and controlled pulse width trains with variable duty cycles, allowing for precise thermal and non-thermal treatments by alternating between low and high power levels to minimize tissue damage and enhance therapeutic outcomes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous wave (CW) laser is used for photocoagulation treatment, then therapeutic effect is achieved, but collateral photocoagulation damage occurs to surrounding tissues
Solution Approach 1:
The patent applies periodic pulsed laser action instead of continuous wave laser. The laser delivers short pulses (e.g., 10-100 microseconds) separated by longer intervals, allowing thermal diffusion to occur between pulses. This periodic action confines thermal damage to the target tissue while sparing surrounding healthy tissue, resolving the contradiction between achieving therapeutic effect and avoiding collateral damage.
Solution Approach 2:
The patent dynamically adjusts laser parameters including pulse width, pulse repetition frequency, and duty cycle based on treatment requirements. By making the laser operation dynamic rather than static continuous delivery, the system can optimize thermal confinement to achieve reliable therapeutic effects while minimizing harmful effects on surrounding tissues.
2Measurement precision
If Q-switched laser with very short pulses is used, then selective tissue targeting is achieved, but plasma formation causes mechanical damage to targeted tissue
Solution Approach 1:
The patent changes the laser pulse duration parameter from extremely short Q-switched pulses (nanoseconds) to longer pulses (microseconds to milliseconds). This parameter change prevents plasma formation and associated mechanical damage while maintaining selective tissue targeting through appropriate wavelength selection and pulse duration optimization for thermal confinement.
Solution Approach 2:
The patent converts the potentially harmful plasma formation effect into a beneficial purely thermal effect by using longer pulse durations. This eliminates the mechanical shock wave and bubbling damage while preserving the selective photothermal effect, turning a harmful mechanism into a beneficial one for tissue treatment.
3Adaptability or versatility
If DPSS laser is used for retinal treatment, then treatment capability is provided, but unstable performance and high sensitivity to temperature reduce treatment safety
Solution Approach 1:
The patent implements feedback control mechanisms to monitor and stabilize laser output parameters. By using feedback to compensate for temperature-induced variations and other instabilities, the system maintains reliable and safe treatment delivery despite the inherent sensitivity of DPSS lasers to temperature changes.
4Temperature
If long pulse duration is used for photocoagulation, then thermal effects are achieved, but heat dissipation prevents reaching therapeutic temperature
Solution Approach 1:
The patent uses periodic pulsed laser delivery with pulse durations optimized for thermal confinement (10 microseconds to 10 milliseconds). The pulsing allows heat to accumulate during the pulse while limiting dissipation, achieving therapeutic temperatures without excessive energy loss to surrounding tissues.
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 enables precise control over laser energy delivery, reducing collateral damage and optimizing therapeutic effects by confining thermal effects to target tissues, thereby improving treatment efficacy and safety.
Implementation Method 1
irradiating the tissues with a high fluence of laser radiation, that in turn is absorbed by the by tissue chromophores, most significantly melanin. The chromophores build up heat that diffuses to surrounding tissues to cause photocoagulation
Implementation Method 2
All of the above laser treatments involve longer pulses of a continuous wave (CW) laser to photo-coagulate the tissues
Implementation Method 3
The chromophores build up heat that diffuses to surrounding tissues to cause photocoagulation of the adjacent tissues
Implementation Method 4
an optical chopper positioned to interrupt the continuous laser beam and produce a pulsed output... with an optical chopper positioned to interrupt the continuous laser beam and produce a pulsed output, with a duty cycle that provides for substantial confinement of thermal effects at a target site
Data Source
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AI summary
A method and system for thermal and non-thermal laser treatments includes a visible laser source. A laser beam in the visible spectrum is generated by the visible laser source and produces a modulated laser output. Laser controls allows the user to generate the pulsed output with variable pulse characteristics to provide selective, localized and user controlled thermal and or non-thermal biological effects at a targeted tissues. This laser system modulates the delivered laser energy to produce accurate and selective targeting of the pigmented cells of the treated tissues to induce therapeutic effects via gentle warming of the cells without significant collateral damage to surrounding tissues.