Share Email Print
cover

Proceedings Paper

Noninvasive dosimetry and monitoring of TTT using spectral imaging
Author(s): G. Schuele; F. E. Molnar; D. Yellachich; E. Vitkin; L. T. Perelman; D. Palanker
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Transpupillary thermo therapy (TTT) is a slow (60 seconds) photothermal treatment of the fundus with a near-infrared (780-810nm) laser irradiating a large spot (0.5- 1. mm) on the retina. Due to high variability in ocular tissue properties and the lack of immediately observable outcome of the therapy, a real-time dosimetry is highly desirable. We found that fundus spectroscopy and spectrally-resolved imaging allow for non-invasive real-time monitoring and dosimetry of TTT. A 795nm laser was applied in rabbit eyes for 60 seconds using a 0.86mm retinal spot diameter. The fundus was illuminated with a broadband polarized light, and its reflectance spectra were measured in parallel and cross-polarizations. The fundus was also imaged in selected spectral domains. At irradiances that do not create ophthalmoscopically visible lesions the fundus reflectance increases at the wavelengths corresponding to absorption of the oxygenated blood indicating the reduced concentration of blood in the choroid. Vasoconstrictive response of the choroidal and retinal vasculature during TTT was also directly observed using spectrally-resolved imaging. At irradiances that produce ophthalmoscopically visible lesions a rapid reduction of the fundus reflectance was observed within the first 5-10 seconds of the exposure even when the visible lesions developed only by the end of the 60 second exposure. No visible lesions were produced where the laser was terminated after detection of the reduced scattering but prior to appearance of the enhanced scattering.

Paper Details

Date Published: 7 March 2006
PDF: 7 pages
Proc. SPIE 6138, Ophthalmic Technologies XVI, 61381G (7 March 2006); doi: 10.1117/12.642338
Show Author Affiliations
G. Schuele, Stanford Univ. (United States)
F. E. Molnar, Stanford Univ. (United States)
D. Yellachich, Stanford Univ. (United States)
E. Vitkin, Beth Israel Deaconess Medical Ctr., Harvard Medical School (United States)
L. T. Perelman, Beth Israel Deaconess Medical Ctr., Harvard Medical School (United States)
D. Palanker, Stanford Univ. (United States)


Published in SPIE Proceedings Vol. 6138:
Ophthalmic Technologies XVI
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

© SPIE. Terms of Use
Back to Top