Radiant energy – Luminophor irradiation
Reexamination Certificate
1998-12-17
2001-06-26
Hannaher, Constantine (Department: 2878)
Radiant energy
Luminophor irradiation
C250S459100, C250S227220
Reexamination Certificate
active
06252235
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for imaging fluorescent particles, and more particularly to an apparatus for imaging fluorescent particles such as leukocytes or the like stained with a fluorescent dye.
2. Description of the Prior Art
In the medical field, platelet preparations and erythrocyte preparations are produced by extracting platelets and erythrocytes from whole blood. These platelet and erythrocyte preparations are each used for blood transfusions, and it is undesirable for either preparation to contain leukocytes. It is therefore important to be able to know how many leukocytes the preparations contain. Conventionally this is done by placing a sample platelet preparation in a NAGEOTTE chamber, staining with a fluorescent dye, projecting an excitation light onto the sample and counting leukocytes via a microscope. Specifically, a 50 microliter sample is taken from a 200 or 400 milliliter bag of platelet preparation, the leukocytes in the sample are counted and converted to a leukocytes count for the whole bag. This is a tiring, inefficient, time-consuming task that has to be done by skilled personnel.
An apparatus has been proposed to enable leukocytes to be counted, instead, by staining the leukocytes with a fluorescent dye, illuminating the sample with an excitation light having predetermined wavelengths, using a CCD camera or the like to image the sample and then analyzing the images to obtain a count of the leukocytes. However, the solution containing the stained leukocytes also contains fluorescent dye that also emits fluorescent light. Thus, since not only the stained leukocytes but also the fluorescent dye itself is excited by the excitation light, there is a marked decrease in the contrast of the leukocytes that it is desired to observe or image. In some cases, the contrast may worsen to the point that the leukocyte images become so buried in the background that they cannot be picked out, making it impossible to count the leukocytes.
An object of the present invention is to provide an apparatus for imaging fluorescent particles that enables the fluorescent particles to be well imaged by reducing the effect of background light.
SUMMARY OF THE INVENTION
To attain the above object, the present invention provides an apparatus for imaging fluorescent particles stained with a fluorescent dye, comprising an imaging vessel for collecting and accommodating the fluorescent particles in a bottom portion thereof, means for generating an excitation light for exciting the fluorescent particles, illumination means for illuminating only a vicinity of the bottom portion of the imaging vessel by the excitation light, and means for obtaining images from below the bottom portion of the imaging vessel.
In accordance with this arrangement, as the fluorescent particles that are the object of interest are accumulated in the bottom part of the imaging vessel and the excitation light is projected on just that bottom part of the vessel, it is possible to reduce background light and thereby improve the contrast of the images obtained.
As a means that can be used to ensure that just the bottom portion of the vessel is illuminated, a cover can be positioned to prevent the upper part of the imaging vessel from being illuminated by the excitation light, or the same effect can be obtained by using a cover with a slit-shaped aperture.
In such a case, the fluorescent particles can be illuminated even more effectively by using a cylindrical lens or the like to convert the thin excitation laser beam into a wide, flat beam in order to illuminate just the bottom portion of the vessel. The same effect can also be obtained by deflecting the excitation light along the bottom portion, or by projecting the excitation light via a bundle of optical fibers the exit end of which is arranged in a straight line.
Thus markedly reducing the amount of background light allows the fluorescent particles to be imaged with high contrast, thereby increasing the reliability of the fluorescent particle count.
Further features of the invention, its nature and various advantages will become more apparent from the accompanying drawings and following detailed description of the invention.
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patent: 5436717 (1995-07-01), Ogino
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patent: 6071748 (2000-06-01), Modlin et al.
patent: 6097025 (2000-08-01), Modlin et al.
Komatsu Akio
Matsui Hiroki
Niino Masao
Adams & Wilks
Gabor Otilia
Hannaher Constantine
Kowa Company Ltd.
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