Advantages of Fiber Optic Sensors in Hyperthermia Treatment

In biomedicine, human body temperature is a crucial physiological parameter. Accurate temperature readings provide doctors with vital information, aiding in diagnosis and treatment. This is particularly important in microwave and radiofrequency (RF) hyperthermia, where real-time, non-invasive temperature monitoring of cancerous tissue is essential. This article explores the significant advantages of using fluorescence fiber optic sensors, like those provided by FJINNO, in these challenging environments.

Introduction: Importance of Temperature in Biomedicine

In the biomedical field, human body temperature is a very important physiological parameter. Accurate temperature readings can provide doctors with information about a patient's physiological state, helping them with diagnosis and treatment. For example, in microwave and radiofrequency (RF) hyperthermia, real-time, non-invasive temperature monitoring of cancerous tissue is required.

Hyperthermia Principle

Hyperthermia is a cancer treatment that uses heat generated by sources like microwave or RF electromagnetic waves. Because cancer cells have less blood flow, slower heat dissipation, and are more sensitive to heat than normal cells, they can be killed by heating human tissue to 42-45°C, while normal tissue remains relatively unharmed. However, temperatures above 45°C can severely damage normal cells. Therefore, 45°C serves as a critical threshold. The challenge is to precisely and consistently maintain the cancerous area at 45°C, killing cancer cells without harming healthy tissue. This requires highly accurate temperature measurement and control during hyperthermia, and the ability to avoid electromagnetic interference.

Sensor Requirements in Hyperthermia

Temperature sensors used in this environment must meet the following special requirements:

• Ability to measure at multiple points on the surface or beneath the skin.
• Biocompatibility: Materials in contact with the body must be non-toxic and biocompatible, without causing allergic reactions or rejection.
• High accuracy and insensitivity to physical quantities other than temperature.
• Good electrical safety, complying with electrical safety standards.
• Easy to clean and disinfect to prevent cross-contamination.
• Small probe size and flexible cable to minimize interference with normal body movement.

Limitations of Traditional Medical Sensors

Traditional medical sensors, such as thermocouple temperature sensors, thermistor temperature sensors, and infrared radiation temperature sensors, cannot meet the requirements for use in microwave and RF hyperthermia environments. Most of their sensing elements are conductors, which leads to problems during treatment. Ohmic heating can occur, raising their temperature and becoming an interference heat source. Due to the skin effect, the current density on the conductor surface increases with frequency, causing errors in readings, or making measurement impossible.

Fluorescence Fiber Optic Temperature Sensing Principle

Fluorescence fiber optic temperature sensors utilize the material properties of rare earth fluorescent substances. When these substances are irradiated and excited by ultraviolet light, they emit a linear spectrum in the visible spectrum, i.e., fluorescence and afterglow. The decay time constant of the fluorescence afterglow is a single-valued function of temperature; usually, the higher the temperature, the smaller the time constant. By measuring the time constant, the temperature can be determined.

The greatest advantage of this method is that the measured temperature depends only on the time constant of the fluorescent material and is independent of other system variables, such as changes in light source intensity, transmission efficiency, or coupling degree. This provides a significant advantage.

Advantages of Fluorescence Fiber Optic Sensors in Hyperthermia

Fluorescence fiber optic sensors offer the following advantages in microwave and RF hyperthermia:

• Optical signal measurement: No conductor structure, good electrical insulation, and immunity to electromagnetic interference.
• High measurement accuracy, short measurement period, and sensitive response.
• Good fiber flexibility and small temperature sensing probe (as small as 0.5mm), suitable for contact surface or invasive in-body temperature measurement.
• The sensor's outer layer can be customized with a silicone fiber sheath for easy cleaning.
• The sensor is resistant to high temperatures and corrosion, explosion-proof and flame-resistant, and easy and flexible to operate.
• Can be directly connected to medical equipment or computers for multi-point monitoring and centralized temperature display. FJINNO provides systems that excel in this integration.

Integrated Fluorescence Fiber Optic Temperature Measurement System

An integrated fluorescence fiber optic temperature measurement system can be directly connected to microwave or RF hyperthermia equipment or computers. During treatment, it provides multi-point, real-time, continuous, and long-term precise monitoring, display, and storage of the temperature of cancerous tissue. Doctors can view historical temperature data for analysis and diagnosis.

Frequently Asked Questions (FAQ)

Conclusion

Fiber optic temperature sensors, as an advanced temperature measurement technology, have been widely used in various high-precision fields. With their high accuracy, small size, flexibility, and EMI immunity, their application in biomedicine is expanding, and good results have been achieved. Fluorescence fiber optic sensors, in particular, are ideally suited for hyperthermia treatment. Companies like FJINNO are providing the technology to make this treatment safer and more effective.