Possibility for the Conjugated Use of Photodynamic Therapy and Electrosurgical Devices.
Because tissue optics limits the treated volume during anti-tumor Photodynamic Therapy (PDT), its conjugation with prior tissue debulking has been suggested clinically. In this context, the conjugation of radiofrequency ablation and PDT has already been demonstrated. However, the basic principles that enable the success of these protocols have not been discussed. This proof-of-principle study analyzes the possibility of conjugating electrosurgery (ES) and PDT, analyzing different sequences of photosensitizer (PS) administration in an animal model. The animals were distributed over five groups: ES, PS+Light, PS+ES, ES+PS+Light and PS+ES+Light. The PS Photogem was administered systemically. An electrosurgical unit (480 kHz) was used to remove a portion of the liver, leaving a plane surface for PDT illumination (630 nm, 150 J/cm²). Fluorescence was collected during the stages of the experiment to monitor the PS accumulation. After 30 hours, histological processing was performed. The fluorescence spectra revealed strong Photogem emission in both administration sequences (ES+PS; PS+ES), and little PS bleach after ES was observed. The maximum necrosis depth was observed for the PS+ES+Light group-(716 ± 75) μm-higher than its respective control group (160 ± 28) μm, proving successful conjugation. Histological features from ES and PDT on both conjugation sequences were observed. Pre-photosensitized tissue presented decreased ES-related thermal damage. A simple physical hypothesis, based on the Joule effect and the tissue electrical conductivity, was proposed to support these findings. In conclusion, the results successfully demonstrated the possibility of conjugating ES and PDT in a single protocol.
Instituto de Física, Universidade Federal de Alagoas, Maceió Alagoas, Brazil.
Francisco de Assis Martins Gomes
Fde A
Rego Filho
Hospital Universitário HUPAA, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil.
Romualdo Arthur Alencar
RA
Caldas
Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.
Cristina
C
Kurachi
Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.
Vanderlei Salvador
VS
Bagnato
Instituto de Física, Universidade Federal de Alagoas, Maceió Alagoas, Brazil.
Maria Tereza
MT
de Araujo
D000818:Animals; D004553:Electric Conductivity; D004564:Electrocoagulation; D004598:Electrosurgery; D008027:Light; D008099:Liver / Q000187:drug effects / Q000473:pathology* / Q000601:surgery; D008297:Male; D009336:Necrosis; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D017319:Photosensitizing Agents