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Photodynamic therapy using pheophorbide a and Nd:YAG laser.
I Fujishima1, T Sakai, T Tanaka
1Department of Neurosurgery, Seirei Mikatabara General Hospital, Shizuoka.
Neurologia Medico-Chirurgica
|May 1, 1991
Summary
A new photodynamic therapy (PDT) using Pheophorbide a and a Nd:YAG laser shows promise for malignant brain tumors. Combining PDT with hyperthermia achieved complete tumor eradication in rats.
Area of Science:
- Oncology
- Biomedical Engineering
- Photomedicine
Background:
- Malignant brain tumors present significant treatment challenges.
- Photodynamic therapy (PDT) offers a targeted approach.
- Developing effective photosensitizers and activation methods is crucial.
Purpose of the Study:
- To evaluate a novel photodynamic therapy (PDT) method for malignant brain tumors.
- To assess the efficacy of Pheophorbide a (Ph-a) as a photosensitizer activated by a Nd:YAG laser.
- To investigate the combined effects of PDT and hyperthermia.
Main Methods:
- Pheophorbide a (Ph-a) was used as the photosensitizer.
- Activation was achieved using an acoustic Q-switched neodymium yttrium-argon-garnet (Nd:YAG) laser for deep tissue penetration.
- In vitro and in vivo studies were conducted on T9 glioma cells in Fisher 344 rats.
Main Results:
- Ph-a showed a high tumor-to-normal brain tissue concentration ratio (7.5:1) in rats.
- In vitro, Ph-a with laser irradiation significantly reduced T9 glioma cell survival (68.8%).
- In vivo, PDT eradicated tumors in 4/6 rats; combining PDT with hyperthermia eradicated tumors in all 6 rats.
Conclusions:
- Pheophorbide a activated by a Nd:YAG laser is effective for PDT of malignant brain tumors.
- The combination of PDT and hyperthermia demonstrates significant potential for complete tumor eradication.
- This combined approach offers a promising strategy for brain tumor treatment.