J. Van Den Boogert et al., Photodynamic therapy for esophageal lesions: Selectivity depends on wavelength, power, and light dose, ANN THORAC, 68(5), 1999, pp. 1763-1769
Citations number
19
Categorie Soggetti
Cardiovascular & Respiratory Systems","Medical Research Diagnosis & Treatment
Background. Photodynamic therapy with 5-aminolevulinic acid-induced photose
nsitization could selectively eliminate esophageal epithelial lesions. This
study aimed at optimizing laser parameters for 5-aminolevulinic acid photo
dynamic therapy of the normal rat esophagus.
Methods. Sixty rats received 200 mg/kg 5-aminolevulinic acid orally and wer
e illuminated 3 hours later with either 633 or 532 nm light (n = 30 for eac
h group) through an endoesophageal balloon catheter. Rats received either 8
.3 or 25 J/cm diffuser, applied with a 33, 100, or 300 mW/cm diffuser. Duri
ng illumination, tissue fluorescence measurements and light dosimetry were
done. Rats were sacrificed at 48 hours after photodynamic therapy.
Results. During illumination, protoporphyrin IX fluorescence declined faste
r when a higher power output was used. Fluence rate at the esophageal surfa
ce was highest for 633-nm light. At 532 nm, light caused less damage to the
epithelium and muscle than 633-nm light. Illumination with 33 mW resulted
in selective epithelial ablation, whereas illumination with 300 mW caused m
uscle damage with minor epithelial damage.
Conclusions. The assumed selective epithelial damage of 5-aminolevulinic ac
id photodynamic therapy in the esophagus largely depends on the combination
of wavelength, power, and light dose applied. Most selective epithelial da
mage was found when low-power 633-nm light was used. (C) 1999 by The Societ
y of Thoracic Surgeons.