The Use of Lipid Emulsion as an Intravesical Medium to Disperse Light in the Potential Treatment of Bladder Tumors

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Abstract
An obstacle to satisfactory treatment of early bladder cancer with hematoporphyrin derivative-photoradiation therapy is nonuniform illumination of the bladder mucosa. The characteristics and attenuation of laser light passing through the dispersion medium was determined. Bladder simulation was achieved with the use of 5 different sizes of round-bottom flasks. Intralipid was the dispersion medium. For each flask, 6 different concentrations of the dispersion medium were used. An Argon ion laser was used to stimulate a dye laser at 630 nm. The laser was directed toward the center of the flasks via a fiberoptic cable and energy concentration at 7 different angles was measured. The optimal medium was a 1:100 dilution in Intralipid with water, which produced an almost uniform dispersion of light in the walls of the flask. There is a linear correlation between power as measured at the fiber tip and the amount of radiation detected on the walls of the flasks. After determining optimal concentration of medium, the amount of time needed for a desired energy (J/cm2) to treat a tumor was calculated. This calculation was based on the size of the bladder and the power as measured at the fiber tip. It is possible to treat the entire mucosa of the bladder with a uniform dose of photoradiation energy.