Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
2000-11-02
2002-10-15
Philogene, Haissa (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C315S149000, C315S224000, C315S362000, C600S160000, C600S178000
Reexamination Certificate
active
06465968
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for displaying fluorescence information, wherein excitation light is irradiated to a region of interest in a living body, intrinsic fluorescence produced by an intrinsic dye in the living body is detected, and information in accordance with characteristics of the intrinsic fluorescence is displayed.
2. Description of the Related Art
There have heretofore been proposed fluorescence information displaying techniques utilizing characteristics such that, in cases where excitation light having wavelengths falling within an excitation wavelength range for an intrinsic dye in a living body is irradiated to the living body, an intensity of fluorescence produced by the intrinsic dye in the living body varies for normal tissues and diseased tissues. With the proposed fluorescence information displaying techniques, excitation light having predetermined wavelengths is irradiated to a region of interest in a living body, the fluorescence produced by an intrinsic dye in the living body is detected, and the location and the infiltration range of diseased tissues are displayed as a fluorescence image.
Ordinarily, when excitation light is irradiated to a region of interest in a living body, the fluorescence having a high intensity is produced by normal tissues, and the fluorescence having a low intensity is produced by diseased tissues. Therefore, by measurement of the fluorescence intensity, a judgment as to the state of a disease is capable of being made.
Basically, apparatuses for displaying fluorescence information comprise excitation light irradiating means for irradiating excitation light, which has wavelengths falling within an excitation wavelength range for an intrinsic dye in a living body, to the living body, imaging means for detecting fluorescence produced by the intrinsic dye in the living body and forming a fluorescence image of the living body, and image displaying means for receiving the output from the imaging means and displaying the fluorescence image. In many cases, the apparatuses for displaying fluorescence information take on the form built in endoscopes, which are inserted into the body cavities, colposcopes, operating microscopes, or the like.
However, the aforesaid apparatuses for displaying fluorescence information have the problems described below. Specifically, since a region in a living body has protrusions and recesses, the distance between the light source of the excitation light irradiating means and the region of interest in the living body is not uniform. Therefore, ordinarily, the irradiance of the excitation light at the living body portion, which is exposed to the excitation light, is non-uniform. The intensity of fluorescence is approximately in proportion to the irradiance of the excitation light, and the irradiance of the excitation light at the portion, which is exposed to the excitation light, is in inverse proportion to the square of the distance between the light source of the excitation light irradiating means and the portion, which is exposed to the excitation light. Accordingly, the problems occur in that diseased tissues, which are located close to the light source, produce the fluorescence having a higher intensity than the intensity of the fluorescence produced by normal tissues, which are located remote from the light source. The problems also occur in that the intensity of the fluorescence from normal tissues, which are located at a position inclined with respect to the excitation light, becomes markedly low. Thus if the irradiance of the excitation light is non-uniform, the intensity of the fluorescence will vary in accordance with the level of the irradiance of the excitation light, and therefore an error will often be made in the judgment of the state of a disease.
A fluorescence imaging technique has been proposed in, for example, “Fluorescence Imaging of Early Lung Cancer,” Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vol. 12, No. 3, 1990. With the proposed technique, the fluorescence, which is produced by an intrinsic dye in an region of interest in a living body when the region of interest is exposed to excitation light, is separated into an intensity of the green wavelength region (hereinbelow referred to as the “green region intensity G”) and an intensity of the red wavelength region (hereinbelow referred to as the “red region intensity R”). An image operation is then performed in accordance with division of the red region intensity R and the green region intensity G by each other, and the results of the division are displayed. The proposed technique utilizes the findings in that the spectrum of the fluorescence produced by normal tissues is different from the spectrum of the fluorescence produced by diseased tissues. Specifically, when the spectrum of the fluorescence, which is produced by the intrinsic dye at normal tissues in the living body, and the spectrum of the fluorescence, which is produced by the intrinsic dye at diseased tissues in the living body, are compared with each other, in particular, the intensity of the green region of the spectrum obtained from the diseased tissues is markedly lower than the intensity of the green region of the spectrum obtained from the normal tissues. Therefore, the degree of reduction in the intensity of the green region intensity G of the fluorescence, which is produced from the diseased tissues, as compared with the intensity of the green region intensity G of the fluorescence produced from the normal tissues, is markedly higher than the degree of reduction in the intensity of the red region intensity R of the fluorescence, which is produced from the diseased tissues, as compared with the intensity of the red region intensity R of the fluorescence produced from the normal tissues. Therefore, only the fluorescence from the diseased tissues can be specifically extracted by the division of R/G and can be displayed as an image.
Specifically, with the proposed technique, the term of the fluorescence intensity depending upon the distance between the excitation light source and the region of interest in the living body and the distance between the region of interest in the living body and the fluorescence receiving means is canceled, and information reflecting only the difference in fluorescence spectrum pattern is obtained.
However, heretofore, research has not been conducted sufficiently with respect to a combination of detection wavelengths, at which the difference between the pattern of a fluorescence spectrum obtained from normal tissues and the pattern of a fluorescence spectrum obtained from diseased tissues occurs markedly. Therefore, there have been the problems in that a desirable combination of detection wavelengths cannot be presented with numerical values.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a method of displaying fluorescence information, wherein fluorescence components having two different wavelengths are extracted from fluorescence, the two different wavelengths having been specified with numerical values as an appropriate combination of detection wavelengths, at which a difference between a pattern of a fluorescence spectrum obtained from normal tissues and a pattern of a fluorescence spectrum obtained from diseased tissues occurs markedly, light intensities of the extracted fluorescence components are detected, and information in accordance with a ratio between the light intensities of the extracted fluorescence components is displayed with a high reliability.
Another object of the present invention is to provide a method of displaying fluorescence information, wherein fluorescence components having wavelengths falling within a certain wavelength region are extracted from fluorescence, the certain wavelength region having been specified with numerical values as an appropriate detection wavelength region, at which a difference between a fluorescence intensity of fluorescence produced fr
Fuji Photo Film Co. , Ltd.
Philogene Haissa
Sughrue & Mion, PLLC
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