Acceleration of ALA‐induced PpIX fluorescence development in the oral mucosa

Abstract

Abstract Background and Objectives The development of 5‐aminolevulinic acid (ALA)‐induced tissue fluorescence is optimal 2–4 hours after ALA application. Goal of this work was to develop a means of accelerating oral topical ALA‐induced tissue fluorescence. Study Design/Materials and Methods In 300 hamsters, DMBA (9,10 dimethyl‐1,2‐benzanthracene) cheek pouch carcinogenesis produced dysplasia in 3–5 weeks. Topical application of 20% ALA in Eucerin was followed by localized ultrasound treatment (1, 3.3 MHz) in 150 animals. In 75 animals, ALA was applied in an Oral Pluronic Lecithin Organogel (OPLO—an absorption enhancer) vehicle. Seventy‐five animals received only topical ALA in Eucerin. Hamsters were sacrificed and cryosections underwent fluorescence measurements, histological evaluation, 20–180 minutes after ALA application. One‐way ANOVA detected independent effects of pathology on laser‐induced fluorescence (LIF). Two‐way ANOVA tested for independent effect of pathology and of OPLO, ultrasound, and interaction effects. Results Ultrasound significantly ( P < 0.05) accelerated tissue fluorescence development. Conclusions Low‐frequency ultrasound can accelerate ALA‐induced fluorescence development. Lasers Surg. Med. 32:185–188, 2003. © 2003 Wiley‐Liss, Inc.