Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2000-12-04
2003-06-03
Paik, Sang (Department: 3742)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
Reexamination Certificate
active
06574502
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for displaying a fluorescence image, wherein a fluorescence image in accordance with characteristics of fluorescence, which is produced from a measuring site in a living body when the measuring site is exposed to excitation light, is displayed.
2. Description of the Related Art
There have heretofore been proposed apparatuses for displaying a fluorescence image by 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 apparatuses for displaying a fluorescence image, 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 an image.
FIG. 10
shows typical fluorescence spectra of the fluorescence produced from normal tissues and the fluorescence produced from diseased tissues, which fluorescence spectra have been measured by the inventors. It is assumed that the thus produced fluorescence results from superposition of the fluorescence produced by various kinds of intrinsic dyes in the living body, such as FAD, collagen, fibronectin, and porphyrin. 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, in cases where information in accordance with the fluorescence intensity is displayed, a person who sees the displayed information is capable of recognizing the state of the diseased tissues. In many cases, the apparatuses for displaying a fluorescence image 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 a fluorescence image have the problems described below. Specifically, in cases where a region in a living body has protrusions and recesses, the distance between an excitation light irradiating system and the measuring site in the living body is not uniform. Therefore, it often occurs that the irradiance of the excitation light at the living body portion, which is exposed to the excitation light, is not 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 excitation light irradiating system 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 low.
In order for the adverse effects of differences in measuring conditions, such as a measuring distance and a measuring angle, to be eliminated, there has been proposed an apparatus for displaying a fluorescence image by utilizing the characteristics such that a pattern of a fluorescence spectrum varies for the fluorescence produced from the normal tissues and the fluorescence produced from the diseased tissues. With the proposed apparatus for displaying a fluorescence image, as illustrated in
FIG. 11
, a quotient of division R/G is calculated from light intensity R of a red wavelength region and light intensity G of a green wavelength region. Also, information in accordance with the results of the division R/G is displayed on a monitor. In this manner, the location and the infiltration range of the diseased tissues are displayed as an image.
With the proposed apparatus for displaying a fluorescence image, 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 by the division R/G. Therefore, 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 can be ignored. However, the light intensity of the intrinsic fluorescence components of the green region in the intrinsic fluorescence produced from the diseased tissues is low. As a result, it often occurs that division by a value of zero occurs, and the operation becomes unstable.
An apparatus for displaying a fluorescence image as illustrated in
FIG. 12
has been proposed in, for example, Japanese Unexamined Patent Publication No. 9(1997)-327433. With the proposed apparatus for displaying a fluorescence image, excitation light L
9
is produced by an excitation light source
401
and is irradiated to a measuring site
60
. Fluorescence L
10
, which is produced from the measuring site
60
when the measuring site
60
is exposed to the excitation light L
9
, is acquired via an endoscope
402
. Fluorescence components of a red wavelength region and fluorescence components of a green wavelength region are selected from the fluorescence L
10
by use of mirrors
403
,
404
and filters
405
,
406
. The fluorescence components of the red wavelength region and the fluorescence components of the green wavelength region are detected respectively by high-sensitivity charge coupled device (CCD) image sensors
407
and
408
. An image signal representing the fluorescence components of the red wavelength region, which image signal has been obtained from the CCD image sensor
408
, is fed into an R signal input terminal of a color monitor
409
. Also, an image signal representing the fluorescence components of the green wavelength region, which image signal has been obtained from the CCD image sensor
407
, is fed into a G signal input terminal and a B signal input terminal of the color monitor
409
. In this manner, relative intensities of the image signal representing the fluorescence components of the red wavelength region and the image signal representing the fluorescence components of the green wavelength region are displayed as a change in color on the color monitor
409
.
With the apparatus for displaying a fluorescence image proposed in Japanese Unexamined Patent Publication No. 9(1997)-327433, there is no risk that division by a value of zero will occur. Also, the display color on the monitor changes in accordance with a ratio between the light intensity of the red wavelength region and the light intensity of the green wavelength region. Therefore, the person who sees the image displayed on the monitor is capable of recognizing the state of the diseased tissues in accordance with the display color.
However, the fluorescence, which is produced from the living body tissues when the living body tissues are exposed to the excitation light, is weak. With the apparatus for displaying a fluorescence image proposed in Japanese Unexamined Patent Publication No. 9(1997)-327433, only the light intensity of the red wavelength region and the light intensity of the green wavelength region are detected from the weak fluorescence, and a fluorescence image is formed. Therefore, the apparatus for displaying a fluorescence image proposed in Japanese Unexamined Patent Publication No. 9(1997)-327433 has the problems in that the efficiency, with whic
Fuji Photo Film Co. , Ltd.
Paik Sang
LandOfFree
Apparatus for displaying fluorescence images does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for displaying fluorescence images, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for displaying fluorescence images will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3156480