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Proceedings Paper

Small isotrope probes for in vivo measurements of fluence rate
Author(s): Ivan S. Melnik; Igor Kravchenko
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Paper Abstract

Optical fiber probes with isotropic response for direct measurement of fluence rate in tissue were studied. Two methods of probe fabrication were considered: in the first one, the isotropic spheres were fabricated by melting the fiber tips and then coated there with a layer of scattering material, in the second one, the spheres were fabricated from solid scattering material (milk glass). The core diameter of the quartz fiber was 120 micrometers ; maximum diameter of the probes was 420 micrometers . Anisotropy was determined as a standard deviation of light distribution at the isotropic fiber end. The second fiber end was coupled with different light sources: He-Ne, Ga-As lasers, or 200-W lamp. Melted probes had high anisotropy; it was necessary to cover the sphere by 4 or 5 layers to reduce the anisotropy less than 10%. Increase of isotropic response using a multi-layer covering was achieved at the expense of total transmission decrease (less than 1%). Melting technology deals with low reproduction and repetition of isotropic response. Anisotropy of glued probes was from 4.5% to 7.5% and total transmission ranged from 20% to 30%. Glued probes had sufficient mechanical strength to use their in vivo measurements of fluence rate. Because of influence of light coherency significant anisotropy increase was registered if the lamp was replaced by lasers.

Paper Details

Date Published: 18 January 1995
PDF: 11 pages
Proc. SPIE 2323, Laser Interaction with Hard and Soft Tissue II, (18 January 1995); doi: 10.1117/12.199243
Show Author Affiliations
Ivan S. Melnik, Kiev Polytechnic Institute (Ukraine)
Igor Kravchenko, Kiev Polytechnic Institute (Ukraine)


Published in SPIE Proceedings Vol. 2323:
Laser Interaction with Hard and Soft Tissue II
Hans Joerg Albrecht; Guy P. Delacretaz; Thomas H. Meier; Rudolf W. Steiner; Lars Othar Svaasand; Martin J. C. van Gemert, Editor(s)

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