Extraction Of Spectral Information Content Of Port Wine Stains Skin Photosensitizers In Photodynamic Therapy

The information of real-time changes of photosensitizer content in the target tissue is significant for us to understand the photodynamic therapy (PDT) process, improve PDT effect and develop a reasonable particular therapy program. By using of fluorescence spectra technology, the amount of photosensitizer in port wine stains (PWS) skin is monitored during PDT course. Hematoporphyrin monomethyl ether (HMME), a kind of clinical photosensitizer is used. The works and results are as follows:(1)Establish a sound fluorescence spectra collection system. The fluorescence spectrometer of 200-1100nm scanning range with a 440nm semiconductor light source is offered by FU ZHOU Normal University. With the device, the auto-fluorescence spectrum of normal skin and PWS skin are detected. The fluorescence spectra of PWS skin during PDT is collected also.(2)Analyze PWS skin's main fluorescent material source and the fluorophores which dominate PDT-PWS skin's fluorescence spectra. The results illustrate that skin's main auto-fluorescent material source is Flavin Adenine Dinucleotide (FAD) when irritated by 440nm laser and the PDT-PWS skin's fluorescence spectra is a interfered linear superposition of FAD, photosensitizer and photoproduct fluorescence. By constructing basic spectra and establishing linear regression model, the intensity of FAD fluorescence and photosensitizer fluorescence can be derived from single measured spectrum in which the affection of scattering and absorption has been deducted.(3) We use the ratio of photosensitizer fluorescence intensity to FAD fluorescence intensity to indicate the skin photosensitizer content during the PDT course. The clinical experimental results show that: 1. There is a great diversity of sorts in skin photosensitizer content in different people; 2. The information of skin photosensitizer content variation is quite related to PDT effect under the same situation.(4)Through real-time monitoring and analysis to PDT-PWS skin photosensitizer content, a conclusion was achieved that PDT effect could be improved if PWS skin photosensitizer content level is higher or the higher level maintain longer. So an important index, the exiting time and amount of photosensitizer in skin (ETAPS) is adopted to indicate PDT effect. Experiment and patient-tracking result make clear that the index mentioned above is perfectly linear to PWS fading effect, so that ETAPS can be defined as effect-related index.(5)Try to utilize ETAPS to the adjustment of photosensitizer injection approach and dosage, then combining to theory-simulation review the effect improvement. Numerical simulation result show that prolonging the photosensitizer injection time can help improving PDT effect, while clinical experimental infirm that the improvement is inconspicuous perhaps for patient's variable physical condition.