PDD applied in the dog transmissible venereal tumor

The Transmissible Venereal Tumor (TVT) is a very common neoplasic disease in free-roaming dogs which affects the extern genital and presenting resistance to conventional drugs that promote high toxicity. Photodynamic Therapy (PDT) is based in tumor cells irradiation after absorption of photosensitizer substance. At present, the protoporphyrin IX (PP IX) has been explored in PDT due to be endogen, then it does not present toxicity effect. This substance can be obtained by exogenous way through aminolevulinic acid (5-ALA) administration in patient. The aim of this work was establish the optimal conditions for PDD (Phodynamic Diagnosis) to irradiate the tumor after ALA administration through fluorescence spectroscopy to improve the results with PDT. In this research was studied the 5-ALA 20% absorption in TVT of vaginal and penial mucous of a female and a male dog, respectively. This drug was administrated topically and after 30 minutes the fluorescence spectra were collected in intervals of 15 minutes during 120 minutes. The results showed that the maximum peak of PP IX in the tumor was between 60 and 105 minutes after the ALA application. In conclusion, the optimum effect will be achieved irradiating the tumor tissue into this period.