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Bladder PDT with intravesical clear and light scattering media: Effect of an eccentric isotropic light source on the light distribution
Author(s) -
van Staveren Hugo J.,
Bertrams Rob H. P.,
Star Willem M.
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)20:3<248::aid-lsm3>3.0.co;2-q
Subject(s) - diffuser (optics) , fluence , light scattering , materials science , scattering , optics , irradiation , laser , isotropy , biomedical engineering , medicine , light source , physics , nuclear physics
Background and Objective Whole bladder wall photodynamic therapy (PDT) is sometimes performed with a light scattering medium in the bladder, as it is assumed that this will promote a more uniform illumination of the bladder wall. The influence of eccentric placement of an isotropic light emitting diffuser on the homogeneity of the light distribution at the bladder wall is assessed. Study Design/Materials and Methods: Whole bladder wall irradiations were performed at ≈630 nm, and fluence rates were measured with and without controlled amounts of Intralipid® in an ex vivo pig bladder and in vitro in a bladder phantom. Experimental values were compared to Monte Carlo simulations using in vitro bladder optical properties. Results An eccentric diffuser in a clear intravesical medium produces a better uniform illumination than in a light scattering intravesical medium. Also, intravesical light absorption, e.g., by urine, would lead to a substantial loss of the energy delivered in case of light scattering cavity contents. Conclusion The use of a clear intravesical medium guarantees the highest and most uniform fluence rate at the bladder wall during optical irradiation with an isotropic light source in clinical PDT of nonspherical bladders, whereas an intravesical light scattering medium reduces both the magnitude and the uniformity of the fluence rate. Lasers Surg. Medicine 20:248–253, 1997. © 1997 Wiley‐Liss, Inc.