How to use fluorescent fiber to monitor human body temperature with medical microwave electromagnetic interference

Sensor de temperatura de fibra óptica, Sistema de monitoramento inteligente, Fabricante de fibra óptica distribuída na China

1、 The impact of medical microwave electromagnetic interference on human temperature monitoring

Medical microwave electromagnetic interference may have various impacts on traditional human temperature monitoring methods.
Firstly, from the perspective of interference sources, there are numerous devices in the medical environment that generate microwave electromagnetic interference, such as microwave therapy devices. When these devices work, they generate a certain intensity of microwave electromagnetic field. For traditional electronic temperature monitoring devices, such as thermometers based on thermocouple or thermistor principles, their operation relies on the conduction and conversion of electronic signals. Under microwave electromagnetic interference, this electronic signal may be interfered with. Specifically, it manifests as signal distortion or the superposition of noise, which is like mixing noisy background sound into a quiet sound signal, making it difficult to accurately read the originally clear temperature signal.

In terms of the impact on monitoring accuracy, taking medical equipment such as electrocardiographs and electroencephalographs that require precise signals as an example, if subjected to microwave electromagnetic interference, a distortion similar to certain lesions may be superimposed on the detection results such as waveforms, graphics, and images, causing misdiagnosis. Temperature monitoring equipment may misjudge temperature values when subjected to similar interference, affecting the correct assessment of the patient’s temperature status. Moreover, in a medical environment, if multiple devices are used simultaneously, such as microwave equipment operating in conjunction with other electronic monitoring devices, interference may become more complex and severe, thereby affecting the accuracy and reliability of human temperature monitoring. Além disso, microwave electromagnetic interference may also affect the stability of monitoring equipment, leading to equipment malfunctions or abnormal operation, making temperature monitoring unable to proceed normally.

2、 Principle of Fluorescent Fiber Optic Monitoring Human Temperature

Fluorescent fiber optic monitoring of human temperature is mainly based on the response characteristics of fluorescent materials to temperature.
Fluorescent materials have a special energy level structure that transitions from the ground state to the excited state when exposed to appropriate excitation light. Electrons in the excited state are unstable and will return to the ground state through radiative transitions and emit fluorescence. And the characteristics of this fluorescence (such as intensity, lifetime, etc.) are related to temperature. Quando a temperatura muda, the energy level structure inside the fluorescent material will undergo certain changes, which will affect the emission process of fluorescence. Por exemplo, as the temperature increases, the intensity of fluorescence may weaken or the fluorescence lifetime may change.

In a fluorescent fiber optic temperature monitoring system, there is usually an excitation light source that emits light of a specific wavelength, which is transmitted through the fiber optic to the probe site containing fluorescent material. This probe can be placed near the body parts that require temperature monitoring. The fluorescence signal generated when the fluorescent material is excited will be transmitted back to the detector through the optical fiber. The detector will measure the relevant characteristics of fluorescence, such as intensity or lifetime, and then infer the temperature of the environment (in this case, the human body) based on the pre established fluorescence characteristic temperature relationship curve. This temperature monitoring method based on fluorescent optical fibers has unique advantages in medical environments with electromagnetic interference due to the electromagnetic insulation properties of the fibers themselves. Moreover, the loss of fiber optic transmission signals is low, enabling long-distance transmission. The sensor’s optoelectronic components can also be placed far away from the temperature measurement site to avoid harsh environmental interference factors. Além disso, the sensing method of fluorescence fiber optic temperature measurement technology often uses quartz fiber optic. In radiation temperature measurement, fiber optic replaces the spatial transmission optical path of conventional thermometers, making the interference factors such as dust, mist, and water vapor have little impact on the measurement results. Moreover, fiber optic has small mass, small cross-section, and bendable transmission, which can measure the temperature of invisible working spaces and facilitate installation and use under special working conditions.

3、 Application case of fluorescent fiber optic monitoring of human body temperature in the medical field

（1） Temperature monitoring in tumor hyperthermia

During tumor hyperthermia, precise control of the temperature of tumor tissue is required. Por exemplo, microwave hyperthermia or radiofrequency hyperthermia aim to heat the tumor to an effective therapeutic temperature range while avoiding excessive damage to surrounding normal tissues. If the tumor temperature is below the treatment temperature, it may promote the spread of tumor tissue; If the temperature of the tumor is too high, it may damage normal human tissue.
Fluorescent fiber optic temperature sensors play an important role in this process. The probe is non-conductive, and the probe made of glass and polymer is fully suitable for applications with strong magnetic fields, microwaves, and radio frequency currents, which can avoid high voltage applied to the patient causing electric shock and electromagnetic interference on measurement data. Fluorescent fiber optic sensors can monitor the temperature changes of tumor tissue in real time and accurately. Doctors can adjust the output power and other parameters of thermal therapy equipment in a timely manner based on the monitored temperature data, ensuring the effectiveness and safety of thermal therapy.

（2） Human body thermal therapy fluorescence fiber temperature online monitoring system (FJINNO)

In the field of biomedical science, human body temperature is a very important physiological parameter. The FJINNO system can perform real-time and non-destructive monitoring of the temperature of human cancerous tissues during microwave and radiofrequency hyperthermia. The system can monitor the trend of human temperature changes online and work in automatic temperature control mode. It has the ability to resist electromagnetic interference and can timely monitor alarm information. It can also operate normally in high magnetic field environments. This helps doctors better grasp the human body temperature during the thermal therapy process, in order to make more scientific treatment decisions.

（3） Application of multi-channel precise fiber optic temperature measurement in therapeutic microwave

During the microwave therapy process, a fluorescence fiber optic temperature measurement system can be used to detect real-time temperature information at the lesion site. And industrial computers can be used to control the output power of microwave output systems based on temperature information, forming a closed-loop control of temperature and output power. On the one hand, this ensures the microwave thermal therapy temperature at the lesion site, which is beneficial for improving the thermal therapy effect; On the other hand, to avoid adverse effects on patients caused by excessively high or low temperatures during the thermal therapy process. This multi-channel precise fiber optic temperature measurement method can meet the accurate monitoring needs of different parts or depths of tissue temperature in microwave therapy.

4、 How to solve the problem of fluorescence fiber monitoring human temperature under medical microwave electromagnetic interference

（1） Utilizing the inherent characteristics of fluorescent optical fibers

Advantages of electromagnetic insulation
The material and structural characteristics of fluorescent optical fibers determine their inherent electromagnetic insulation properties. In the medical microwave electromagnetic interference environment, this characteristic enables optical fibers to transmit temperature related optical signals without being affected by electromagnetic interference like traditional metal wires transmit electronic signals. Por exemplo, in the vicinity of microwave thermal therapy equipment, traditional electronic temperature sensors may generate induced currents due to microwave electromagnetic fields, resulting in inaccurate temperature measurement results, while fluorescent fiber optic sensors can work normally, accurately transmit fluorescent signals, and thus achieve precise monitoring of human body temperature.
Probe Material and Design
The probe of the fluorescent fiber optic temperature sensor is made of non-conductive materials such as glass and polymer. These materials do not generate induced currents in microwave environments, avoiding the impact of electromagnetic interference on temperature measurement accuracy caused by the probe itself. Moreover, the design of the probe can be optimized according to different monitoring requirements, such as the size can be made very small (up to 0.5mm at the minimum), suitable for contact type surface or in vivo temperature measurement. When monitoring human body temperature, it can more accurately locate the parts that need to be measured, while reducing invasive effects on the human body.

（2） Adopting advanced demodulation technology

Based on fluorescence intensity ratio technology
Fiber optic temperature sensors based on fluorescence intensity ratio technology can improve anti-interference performance. This technology determines temperature by measuring the ratio of different fluorescence intensities, and is less sensitive to environmental interference (including medical microwave electromagnetic interference) compared to simply measuring fluorescence intensity. Por exemplo, in the presence of microwave interference, even if the absolute value of fluorescence intensity fluctuates due to interference, the intensity ratio may still remain relatively stable, accurately reflecting the temperature value. Through this method, it is possible to more reliably monitor human body temperature in complex medical electromagnetic environments.

（3） System integration and optimizatino

Closed loop control of temperature and power
In the process of medical microwave hyperthermia, a fluorescent fiber temperature measurement system is used to detect the temperature information of the lesion in real time, and then an industrial computer is used to control the output power of the microwave output system based on the temperature information, forming a closed-loop control of temperature and output power. This can ensure the accuracy of temperature monitoring and keep the thermal therapy temperature within an appropriate range in the presence of microwave electromagnetic interference. On the one hand, it ensures the thermal therapy effect, and on the other hand, it avoids the problem of inaccurate temperature measurement caused by unstable microwave power or electromagnetic interference.
Multi channel monitoring and centralized display
The multi-channel fluorescent fiber temperature monitoring system can simultaneously monitor the temperature of multiple parts of the human body. And it can display these monitoring data centrally, making it convenient for medical staff to comprehensively and timely understand the patient’s temperature status. When facing microwave electromagnetic interference in medical environments, multi-channel systems can improve the reliability of temperature monitoring through comprehensive analysis and comparison of data. Por exemplo, if the data of a certain channel is disturbed and abnormal, the data of other channels can be used as a reference to assist in determining the true temperature situation.

5、 Technological progress in monitoring human temperature using fluorescent optical fibers in medical microwave electromagnetic interference

（1） Improved sensor performance

Higher precision and resolution
With the development of technology, the measurement accuracy and resolution of fluorescent fiber optic temperature sensors in medical microwave electromagnetic interference environments continue to improve. Por exemplo, some new sensors can achieve a resolution of 0.02 ℃ or even higher, which enables more accurate capture of small temperature changes when monitoring human body temperature. This high-precision measurement is crucial in medical applications such as tumor hyperthermia that require extremely strict temperature requirements. During microwave hyperthermia, temperature monitoring accurate to 0.02 ℃ can more precisely control the heating degree of tumor tissue, avoid damage to surrounding normal tissue, and improve the effectiveness of tumor treatment.
Better stability and reliability
New materials and processes have been applied to the manufacturing of fluorescent fiber temperature sensors, improving the stability and reliability of the sensors under medical microwave electromagnetic interference. Por exemplo, special packaging techniques are used to protect fluorescent materials and optical fibers from damage or performance degradation during long-term use in microwave environments. Ao mesmo tempo,, in terms of sensor design, the probe structure and fiber optic connection method have been optimized to reduce measurement errors caused by external interference (including microwave electromagnetic interference), enabling the sensor to work stably and reliably for a long time, and continuously and accurately monitor human body temperature.

（2） Multi functional integration and intelligent development

Multi functional integration
Modern fluorescent fiber temperature monitoring systems are beginning to integrate multiple functions. In addition to basic temperature monitoring functions, it may also integrate functions such as data storage and analysis. In the medical microwave electromagnetic interference environment, this multifunctional integration can better meet medical needs. Por exemplo, the system can automatically store temperature data of patients during thermal therapy and analyze this data to provide information such as temperature trends, providing more comprehensive basis for doctors’ diagnosis and treatment. Ao mesmo tempo,, some systems may also integrate communication functions with other medical devices (such as microwave thermal therapy equipment) to achieve more intelligent collaborative work.
Intelligent development
With the development of artificial intelligence and big data technology, fluorescent fiber temperature monitoring systems are also moving towards intelligence. Under medical microwave electromagnetic interference, intelligent systems can automatically identify and eliminate abnormal data caused by interference by learning and analyzing a large amount of temperature data. Por exemplo, using machine learning algorithms, the system can determine whether the currently monitored temperature data is affected by microwave electromagnetic interference based on historical data and normal temperature change patterns. If so, corresponding corrections or reminders can be made to medical staff. Além disso, intelligent systems can automatically adjust temperature monitoring parameters and strategies based on individual differences and treatment needs of patients, improving the accuracy and effectiveness of temperature monitoring.