US 5,957,960 A · Internal two photon excitation device for delivery of PDT to diffuse abnormal cells

Abstract

A plurality of light sources that emit light having a long wavelength are energized for an extended period of time to increase the likelihood of two photon absorption by cells that have preferentially absorbed a photoreactive agent such as psoralen. The cells are preferably microscopic metastatic cancer cells that are diffusely distributed throughout a treatment site, for example, within an organ. The plurality of light sources are arranged in a spaced-apart array, mounted on a support plate that includes a plurality of conductive traces. A plurality of such arrays are preferably mounted to a flexible sheet that can conform to an outer surface of an organ being treated. Because the light emitted by the light sources is in the infrared or near infrared waveband, it penetrates deeply into the tissue at the treatment site. The duration of the treatment and the number of light sources employed for administering the therapy increases the likelihood of two photon absorption by the metastatic cancer cells, which has been shown to activate the photoreactive agent to destroy cancer cells in a tumor, even though the characteristic light absorption waveband of the photoreactive agent is in the ultraviolet waveband.

Claims24

Dependent claims

Apparatus for administering a photodynamic therapy to a treatment site within a patient's body using light having an infrared or near infrared waveband for destroying microscopic, diffuse metastatic cells at the treatment site that have absorbed a photoreactive agent having a characteristic absorption waveband for light that is substantially shorter than the near infrared waveband, comprising:

(a) a support plate on which are disposed a plurality of electrical conductors that are adapted to couple to a source of an electrical current;
(b) a plurality of light sources mounted on the support plate, in electrical contact with the plurality of electrical conductors so that the plurality of light sources are energized by an electrical current conveyed by the plurality of electrical conductors, said light sources emitting the light having a long wavelength that is in the near infrared to infrared waveband;
and
(c) means for directing the light emitted by the plurality of light sources so that the light emitted from one light source crosses the light emitted by a different light source, thereby increasing a likelihood of two photons substantially simultaneously being absorbed by the photoreactive agent in a microscopic, diffuse metastatic cell at the treatment site, to destroy said cell by a photodynamic reaction.

1 more element

Dependencies are inferred from the claim text.

Internal two photon excitation device for delivery of PDT to diffuse abnormal cells

Life of this patent

Internal two photon excitation device for delivery of PDT to diffuse abnormal cells

Life of this patent

Abstract

Claims24