Abstract: An instrument for photodynamic therapy applies treatment light from a dye laser, white light, and ultraviolet fluorescence excitation light from an LED onto a lesion and surrounding areas in a time-multiplexed manner. The reflected white light is analyzed in a spectrometer to determine a correction for the dynamic optical spectral properties of the patient's tissue. Light emitted by fluorescence from the lesion and the surrounding areas is analyzed in another spectrometer, and the results are corrected in a computer, using the correction. An optical switch has been developed for the instrument, using a bistable solenoid and a sled.

Abstract: A method for delivering photodynamic therapy (PDT) while performing dose metric monitoring and treatment feedback-driven control is presented. Photodynamic therapy is initiated with irradiation of light at a first irradiance. A set of fluorescence and reflectance spectroscopic measurements are taken at prescribed intervals during the therapy of the treatment region. Spectra are analyzed to determine dose metrics of the therapy such as fluorescence photobleaching of the sensitizer and blood oxygen status and optical properties of the treatment region. This information is then used to determine an optimal fluence rate given those parameters and the region is irradiated with a second irradiance. This process is continued until either the entire prescribed fluence is delivered to the region or a predetermined extent of photosensitizer bleaching is achieved.

Abstract: In a first embodiment, there is no monitoring, and instead light is delivered according to a predetermined ‘recipe.’ In a second embodiment, the instrumentation provides a means for making the reflectance measurements during therapy without requiring the brief interruption. This device may therefore allow more accurate measurement of treatment-induced changes to the reflectance measurement. In a third embodiment, an adjustable aperture is used to constrict the area of a treatment beam.

Abstract: An instrument for photodynamic therapy applies treatment light from a dye laser, white light, and ultraviolet fluorescence excitation light from an LED onto a lesion and surrounding areas in a time-multiplexed manner. The reflected white light is analyzed in a spectrometer to determine a correction for the dynamic optical spectral properties of the patient's tissue. Light emitted by fluorescence from the lesion and the surrounding areas is analyzed in another spectrometer, and the results are corrected in a computer, using the correction. An optical switch has been developed for the instrument, using a bistable solenoid and a sled.

Abstract: A method for treating aberrant tissue in an animal that includes the following steps. A photosensitive agent is introduced into the blood stream of an animal that has better selectivity for the aberrant tissue than normal tissue to obtain aberrant tissue containing the photosensitizing agent. The aberrant tissue containing the photosensitizing agent is exposed to light to activate the photosensitizing agent to increase permeability of vasculature in the aberrant tissue; and a treating agent is introduced into the bloodstream of the animal, which treating agent passes through the vasculature having increased permeability into the aberrant tissue to treat the aberrant tissue.