The therapeutic efficacy of photodynamic therapy (PDT) of malignant tumors utilizing is related to the capability of the photosensitizer to produce excited singlet molecular oxygen(1-0). This work is devoted to the study on detection of 102 molecules produced by two chlorin-type dyes, pheophorbide a (PPa) and chlorin e6Na (Chl) using a highly sensitive near-infrared spectrometer and comparison of their emitted intensity was made with hematoporphyrin derivative (HpD) and Rhordamin 123 (Rd) in water and methanol. By the irradiation of an Ar or Kr laser light, near-infrared emission spectra around 1.27 jim from the 102 molecules were detected in HpD and Chi aqueous solutions, as well as in Chl, PPa, and Rd methanol solutions. The ratio of their emission intensities at 1.27 jim is found to be 1 : 3.7 : 22 : 15 1 for HpD and Chi aqueous solutions and Chl, PPa, and Rd methanol solutions, respectively. These quantitative results support the conclusion that because of greater production of 102 molecules, PPa and Chl provide more effective SPIE Vol. 1203 Photodynamic Therapy: Mechanisms 11(1990) / 97 photosensitized dyes for the PDT following 102 molecule generation than HpD or Rd when used in conjunction with the laser-excitation and endoscopy.

Date Published: 1 July 1990
PDF: 7 pages
Proc. SPIE 1203, Photodynamic Therapy: Mechanisms II, (1 July 1990); doi: 10.1117/12.17654

Published in SPIE Proceedings Vol. 1203:
Photodynamic Therapy: Mechanisms II
Thomas J. Dougherty, Editor(s)