Mild-temperature photothermal treatment method and system based on photoacoustic temperature measurement and control

• To non-invasively measure temperature changes in tissue with an accuracy of better than 0.5 °C. • To perform real-time temperature imaging of tissue. • To assist in precisely control the temperature of ROI. As a non-invasive technology for tumor treatment, photothermal therapy (PTT) is increasingly applied during clinical treatment. However, due to the lack of non-invasive temperature measurement methods, excessive therapeutic light dose will damage the healthy tissue around the lesion. Monitoring and control the therapy temperature during PTT application is necessary to ensure effective therapy while minimizing thermal damage to adjacent tissue. In order to ensure that the therapy temperature in PTT is stable in the mild range (below 43 °C), it is necessary to design a mild-temperature PTT method and system that can detect and control the temperature in real-time. A mild-temperature photothermal treatment method and system based on photoacoustic temperature measurement and control is proposed in this paper. On the basis of reference temperature, the relative temperature change is measured based on the photoacoustic information, and the treatment temperature of the target area is precisely controlled in real time using the closed-loop temperature control algorithm. Based on the experimental results of agar-based phantoms and pig liver tissue, the proposed system can achieve temperature imaging in real time, and the control steady-state error and overshoot are 0.62 °C and 0.3 % respectively. The results show that our method has the potential for accurate temperature monitoring and closed-loop temperature control during PTT.