Patent ID: 7530947

Claim:
A lesion portion determining method of an infrared observing system, the infrared observing system comprising at least an observing apparatus, the observing apparatus comprising: a light source device which radiates light of a first wavelength band including a wavelength of 805 nm and light of a second wavelength band including a wavelength longer than 805 nm; an image pick-up device which picks up an image of the first wavelength band and an image of the second wavelength band of the object irradiated by the light radiated from the light source device; display means which displays, as any color component of red, green, and blue, the image of the first wavelength band and the image of the second wavelength band that are picked-up by the image pick-up device; the lesion portion determining method comprising: a step of administering an infrared absorbing pigment to a patient; a step of observing a visible range of the infrared absorbing pigment by the observing apparatus; a step of distinguishing a bloodflow state of a tissue depending on the visualizing difference in the infrared absorbing pigment that is observed by the observing apparatus; and a step of distinguishing the bloodflow state of the tissue based on the time until visualizing the infrared absorbing pigment.