Abstract
Novel intratumor photodynamic therapy was performed in canine transmissible sarcoma (CTS) utilizing photofrin and excimer dye laser. First, photofrin was injected intravenously at a dose of 5mg/kg. Thirty-two hours later, a laser-proof plastic tube was penetrated into CTS, followed by a photoradiation from the inside of tumor. The mean diameter of tumor necrosis rapidly increased with an increase of total irradiation energy below 240joule/cm resulting that the mean diameter of tumor necrosis was 17mm at an energy of 120joule/cm (max: 84joule/cm2), as well as 20mm at 240joule/cm (max: 168joule/cm2). Beyond 240joule/cm, its diameter gradually increased to 24mm at 1200joule/cm. The side effect of cutaneous tissue showed an open ulcer at 240joule/cm, and a scar at 120joule/cm. The thermal effect of laser light is minimal or negligible below 120joule/cm.
The total energy in the intratumor photodynamic therapy should be decided with a concern about the sensitivity of normal tissue surrounding malignant tumor against the side effect induced by PDT.
