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Interstitial photodynamic therapy in the canine prostate
L K Lee1, C Whitehurst, Q Chen
1CRC Department of Experimental Radiation Oncology, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, UK.
British Journal of Urology
|January 24, 1998
Summary
Interstitial photodynamic therapy (PDT) using Photofrin in canine prostates created modest tissue necrosis. The minimum light dose for necrosis varied due to unpredictable bleeding around the fiber during interstitial PDT.
Area of Science:
- Oncology
- Biomedical Engineering
- Photomedicine
Background:
- Photodynamic therapy (PDT) is an investigational treatment modality.
- Interstitial PDT utilizes light delivery directly into target tissues.
- Photofrin is a photosensitizer used in PDT.
Purpose of the Study:
- To determine the depth of tissue destruction from interstitial PDT.
- To establish the minimum light dose required for necrosis in interstitial PDT.
- To lay the groundwork for investigational patient therapy.
Main Methods:
- Seven adult beagle dogs received Photofrin; two controls did not.
- Interstitial laser light (630 nm) was delivered via a diffuser fiber to the prostate.
- Tissue necrosis was assessed histologically after light delivery.
Main Results:
- The mean radius of PDT destruction was 5.3 mm; lesions overlapped when fibers were 10 mm apart.
- The mean minimum light dose for necrosis was 84 J/cm².
- Light penetration depth averaged 2.14 mm and did not correlate with necrosis depth.
Conclusions:
- Interstitial PDT with Photofrin in canine prostates yielded moderate tissue necrosis.
- The minimum light dose for necrosis was variable, influenced by unpredictable bleeding.
- Bleeding around the optical fiber interfered with light penetration and treatment consistency.