Single Laser Modulation for Non-Invasive Tissue Temperature Control
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Solution Overview
Problem
Current methods for non-invasive temperature control during laser treatment of biological tissue, such as the fundus, require multiple radiation sources and equipment, increasing costs without ensuring precise temperature control.
Innovation Solution
A method and device utilizing a single modulatable CW laser to produce alternating pulses of treatment and measuring radiation, reducing equipment costs while maintaining precise temperature control by optimizing pulse characteristics and modulation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple radiation sources are used for temperature measurement and treatment, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The single laser radiation source is configured to perform multiple functions: it can operate as a treatment source for coagulation and as a measuring source for temperature detection. The source is modulated to produce different pulse types (treatment pulses and measuring pulses) from the same device, eliminating the need for separate radiation sources while maintaining both treatment and measurement capabilities.
Solution Approach 2:
The laser source is modulated periodically to produce alternating treatment pulses and measuring pulses. The modulation scheme creates distinct pulse patterns where measuring pulses are inserted at regular intervals during the treatment sequence, allowing the single source to serve both therapeutic and diagnostic purposes through temporal separation of functions.
2Measurement precision
If additional measuring radiation source is added, then temperature control precision is improved, but equipment costs increase
Solution Approach 1:
The invention makes the single laser source universal by enabling it to perform both treatment and measurement functions. The source is modulated to produce measuring pulses that can detect temperature changes through thermal expansion of the tissue, while the same source delivers treatment pulses for coagulation. This multi-functionality eliminates the need for additional measuring equipment and reduces overall system cost.
Solution Approach 2:
The treatment laser source serves itself by incorporating measuring capability within the same device. The laser system generates its own measuring pulses from the same active medium and optical path, without requiring external measuring equipment. The system uses its own radiation to both treat and measure temperature, making the treatment source self-sufficient.
3Reliability
If laser power is increased for better coagulation effect, then treatment effectiveness is improved, but tissue damage increases
Solution Approach 1:
The system implements feedback control by continuously measuring temperature through the modulated laser pulses and using this information to adjust the treatment parameters. The measuring pulses detect thermal changes in real-time, allowing the control system to monitor temperature progression and modify subsequent treatment pulses to prevent excessive heating and tissue damage while maintaining effective coagulation.
Solution Approach 2:
The laser delivery is divided into periodic treatment pulses interspersed with measuring pulses. This periodic structure allows the tissue to cool between pulses while the measuring pulses continuously monitor temperature, enabling precise control of the thermal accumulation process. The alternating pattern prevents runaway heating and allows real-time adjustment of treatment parameters.
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
Achieves precise temperature control with reduced equipment expenditure, ensuring accurate measurement and efficient coagulation without additional radiation sources, and minimizing tissue damage.
Implementation Method 1
The pulses of the measuring radiation cause a thermal tissue expansion in the eye, which depends on the temperature caused by the treatment laser and which is evaluable optoacoustically by means of the above-mentioned, e.g., piezoelectric, detectors.
Implementation Method 2
The pulses of the measuring radiation cause a thermal tissue expansion in the eye, which depends on the temperature caused by the treatment laser and which is evaluable optoacoustically by means of the above-mentioned, e.g., piezoelectric, detectors.
Implementation Method 3
The use of a laser as a radiation source has become particularly important because the spectral wavelength of the laser light can be exactly determined (monochromatic, optionally defined wavelengths in the green, yellow, red, or infrared spectral range) and a precise control of the laser light is possible.
Implementation Method 4
For laser coagulation, irradiation times of 20 ms to 500 ms, particularly approximately 100 ms, are commonly used for creating temperatures above 60° C.
Implementation Method 5
The pulses of the measuring radiation cause a thermal tissue expansion in the eye, which depends on the temperature caused by the treatment laser and which is evaluable optoacoustically by means of the above-mentioned, e.g., piezoelectric, detectors.
Data Source
AI summary
A method for non-invasive temperature determination in biological tissue treated with treatment radiation wherein a reaction which depends on the treatment temperature is generated and detected. Measurement radiation pulses and pulses of the treatment radiation are applied to the tissue to be treated successively, in particular in an alternating way, from the same radiation source. A device includes a radiation source, an irradiation lens system, detectors for determining a reaction and a system control suitable for controlling treatment radiation and measurement radiation pulses. The system control generates successive, in particular alternating, pulses of treatment radiation and measurement radiation pulses from one radiation source only, in particular a laser which can be modulated.