Premium
In vivo light transmission spectra in EMT6/Ed murine tumors and dunning R3327 rat prostate tumors during photodynamic therapy
Author(s) -
Ballangrud Åse M.,
Barajas Oscar,
Georgousis Alexia,
Miller Gerald G.,
Moore Ronald B.,
McPhee Malcolm S.,
Tulip John
Publication year - 1997
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1997)21:2<124::aid-lsm3>3.0.co;2-s
Subject(s) - photosensitizer , photodynamic therapy , chemistry , in vivo , absorption (acoustics) , absorption spectroscopy , laser , photochemistry , optics , organic chemistry , physics , biology , microbiology and biotechnology
Background and Objective Variations in the optical coefficients in tissue and the photosensitizer during photodynamic therapy (PDT) will require adjustment of the light dose during the course of therapy. We have studied the dynamics using light transmission spectra for two different tumor models when tetrasulfonated aluminum phthalocyanine (AlPcS 4 ) was used as photosensitizer. Study Design/Materials and Methods Spectra were measured noninvasively in the EMT6/Ed murine tumor model, and with interstitially implanted source and probe fibers in the Dunning R3327‐AT rat tumor model. Measurements were performed in the range 600–840 nm, using a tunable dye laser, a diode laser, and a Ti:Sapphire laser. AlPcS 4 has absorption in the range 600–700 nm with an absorption peak at 670 nm in saline. Results The in vivo spectrum of AlPcS 4 both in the EMT6/Ed tumor model and the Dunning R3327‐AT tumor model differs from the spectrum of AlPcS 4 in saline. The absorption at 670 nm was reduced, whereas the absorption at 640 nm increased. Exposure of phototherapeutic levels of light caused reduced light absorption by the photosensitizer and further spectral shift. Conclusion We found that the AlPcS 4 absorption spectrum changes in a biological environment, and we also observed increased light transmission at the treatment wavelength during PDT in both tumor models. Instability in the absorption spectrum of the photosensitizer may influence the effectiveness of PDT. Lasers Surg. Med. 21:124–133, 1997. © 1997 Wiley‐Liss, Inc.