Experimental photodynamic treatment of canine bladder

In urology, important limiting factors in the application of hematoporphyrin derivative and photodynamic therapy appear to be the problems of standardization of dosimetry and the technique of transurethral photoradiation. Experimental photodynamic therapy on canine bladder with normal and altered epithelium was performed using an argon laser as an energy source. A 630 nanometer wavelength of light was delivered through a quartz-optical fiber with either a regular flat end for focal illumination or a bulb-type end which produced an isotropic light pattern. It was demonstrated that normal canine bladder was resistant to photodynamic therapy and that the bulb tip produced whole bladder illumination. With a moderate light dose of 18 to 30 Joules/cm.2 the effect following whole bladder illumination on the bladder was generalized and superficial. This approach appears to be ideal for treating superficial transitional cell carcinoma of the bladder. Additional work is needed in selecting appropriate energy doses.