| Photothermal therapy, just as its name implies, which is regarding the light source as pyrogens, according to the effect of field heating the diseased areas of tissue to effective treatment temperature, and maintaining a certain heating time, as a result, destroying the structure of diseased tissue, but don’t damage the normal tissue. Currently, thermal therapy of tumor includes coagulation method and laser immunotherapy. Its effectiveness is clinically recognized. However, for the application of photothermal therapy more safely and effectively, the key is to monitor temperature of the organism (especially at the junction of the normal and diseased tissue) accurately and real-time, and feedback those information to light source quickly. Therefore,"effective treatment temperature" and "exposure time" are the two important dosage parameters in tumor photothermal therapy. In order to solve the problem of optimal thermal therapy dose, improve the use of laser effectively and in security, based on this problem, in this paper we explore the law of heat transmission in the organism by photoacoustic imaging technology and the numerical solution of heat conduction, and commit to establish a monitoring platform and optimum proposal for exploring the temperature diffusion in organism during the photothermal therapy. We also employ the photoacoustic spectroscopy to explore the material chemical composition change on the influence of the relationship between the temperature and the signal during the tumor photothermal therapy.First of all, the paper expounds the theoretical basis and the mechanism of photothermal therapy. Overview of what scientists have achieved the research results in the clinical and research trends. Then point out the safe problems of the photothermal therapy and some imaging monitoring technologies applied on it, such as nuclear magnetic resonance imaging monitoring technology, ultrasonic imaging monitoring technology and photoacoustic imaging monitoring technology. Last, we propose the research significance of this subject.Second, we review the development of photoacoustic imaging technology, research status and achievements as well as the application in biomedical, which make the reader, have certain knowledge of the photoacoustic imaging technology.Third, we introduce the theoretical basis of photoacoustic imaging technology in this paper, which is the generated physical mechanism of photoacoustic signal. We analyze the feasible of using the photoacoustic signal to monitor the photothermal therapy in theory and introduce the technical route of photoacoustic imaging monitoring technology. Last, we would explain the feasibility, effectiveness and superiority of regarding the photoachoustic imaging technology as temperature sensor as well as some existing problems.Fourth, we introduce the heat transfer law of biological tissue, and use the finite difference method to solve the heat conduction equation, and then achieve the two-dimensional distribution of temperature field in the organism as well as introduce some important thermal parameters.Fifth, we apply a comprehensive introduction of the integration of experimental device and technical route for treating, monitoring and optimizing during photothermal therapy. We would use the photoachoustic imaging monitoring system on AGAR simulation tissue sample and pig liver sample photothermal therapy. We collected the temperature, time and photoacoustic signal amplitude and gave the relationships between them. Those reflect the wide prospect of clinical application.Sixth, exploring the change of material chemical composition of tumor on the influence of the relationship between temperature and signal in photothermal therapy by photoacoustic spectroscopy, which mean to explore why the photoacoustic signal has a linear relation with temperature under low temperature, and under the action of high temperature is nonlinear relationship. |
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