Photothermal therapy is an emerging tumor treatment technology used for precise treatment of malignant tumors. This technology utilizes materials with high photothermal conversion efficiency to aggregate in tumor tissue, where external therapeutic light sources generate light energy and convert it into thermal energy, selectively killing cancer cells. Compared with traditional treatment methods such as surgery, chemotherapy, and radiotherapy, photothermal therapy has the advantages of non-invasive, targeted, minimal side effects, and repeatable treatment. At the same time, the treatment interval of photothermal therapy is shorter, which can further alleviate the treatment pain of patients. Photothermal therapy technology can also improve immune efficacy by combining synergistic effects with other therapies such as immunotherapy. Due to the lack of real-time and accurate temperature measurement technology, it is difficult to adjust the treatment power in real time, leading to consequences such as overtreatment and seriously affecting the effectiveness of photothermal therapy. Therefore, a non-invasive temperature measurement and regulation method is needed. We propose a photothermal therapy system and method based on adaptive neural network and validate the algorithm and system using an agar-based phantom. The experimental results show that the method has good temperature measurement and control characteristics, with a temperature measurement accuracy of 0.76 °C, and achieves a temperature control accuracy of 0.52 °C within a 21 second adjustment time. It is expected to further improve the safety and stability of PTT.
As a non-invasive, targeted and non-radioactive technology applied to tumor treatment, photothermal therapy is increasingly used in the clinical treatment of tumors due to its high cure rate and few side effects. In order to obtain a better photothermal treatment effect in the actual treatment process, the temperature distribution of the tissue to be treated must be monitored and controlled to prevent unnecessary tissue damage caused by the treatment. Therefore, the photothermal probe and precise control of the treatment temperature become the key to solving the problem. In this paper, a nanoprobe with strong photoacoustic and photothermal properties in one area of near-infrared is designed. At the same time, a photothermal treatment system is designed and combined with nanoprobe for research. This study designed human tissue simulation experiments and found that compared to the case without probe assistance, the photothermal therapy system based on photoacoustic and photothermal probe assistance can achieve temperature control with a temperature error of 1°C , and the temperature control adjustment time has been shortened by 40%, and the overtreatment injury has also been effectively suppressed. More importantly, it is possible to greatly reduce the complexity of the photothermal treatment process in practical applications without the artificial control of continuous laser power. The experimental result shows that the intelligent photothermal treatment method based on the photoacoustic and photothermal nanoprobe is a feasible candidate for tumor treatment and has a good application prospect in the field of tumor treatment.
It is very important for the safety of photothermal therapy to detect the temperature change of the interaction between laser and tissue during photothermal therapy. Using photoacoustic imaging can sensitively reflect the temperature distribution in the tissue. This paper proposes a photoacoustic temperature measurement method combined with quantitative absorption distribution. On the one hand, this method uses the temperature measurement method based on photoacoustic imaging to monitor the temperature change of the target area in real time; on the other hand, it quantifies the absorption distribution of the nanoprobe with the photoacoustic and photothermal effect in the target area. Thereby providing a feedback signal for temperature control during the treatment process, realizing precise control of the target area temperature and reconstruction of the absorption distribution of the target area nanoprobe. The study results verify the feasibility of this method. Compared with traditional quantitative methods, this article considers the dynamic changes of the target area temperature and provides treatment feedback. The feedback control guided by multiple parameters minimizes the damage to the surrounding healthy tissues, while improving the accuracy of reconstruction is helpful for the quantitative assessment of the disease.
Tumor photothermal therapy technology has received a lot of attention in recent years due to its non-invasive and targeted properties. However, how to ensure the safety and effectiveness of the photothermal treatment process poses new challenges to researchers. The field of photothermal therapy urgently needs a non-contact and accurate temperature detection method. In this paper, we have proposed a precise temperature detection technology based on photoacoustic and ultrasonic dual mode which can provide accurate and non-contact temperature measurement, and the temperature information of the light-induced ultrasound signals was fused and applied to temperature detection. To validate our method, temperatures of phantom was measured within the temperature range that simulates the heating process of photothermal therapy, and the calculated temperature measurement error was finally within 1 °C. In particular, it was also verified that the measurement accuracy of this method is 30% higher than that of single photoacoustic temperature detection. The results suggested that our method can be potentially used for temperature monitoring during photothermal therapy.
Variable-spun fiber wave plate can be used to change the polarization state in fiber optic sensing systems. However, the beat length of the birefringence fiber may variation with different operating wavelength, which further leads to the instability of the polarization transforming performance. Based on the relation between the beat length and the operating wavelength, the wavelength sensitivity is simulated for the variable-spun fiber wave plate with different structural parameters (fiber length, spun rate profile and maximum spun rate). The achromatic bandwidth of the qualified fiber plate is discussed. The results have certain reference value for the design, fabrication and evaluation of variable-spun fiber wave plate.
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