WO1995000824A1

WO1995000824A1 - Multi-color fluorescence imaging utilizing deviations in prisms

Info

Publication number: WO1995000824A1
Application number: PCT/SE1994/000575
Authority: WO
Inventors: Sune Svanberg
Original assignee: Spectraphos Ab
Priority date: 1993-06-21
Filing date: 1994-06-14
Publication date: 1995-01-05
Also published as: SE9302147D0

Abstract

The purpose of the invention is to enhance differences between differently fluorescing parts of the object under investigation by pointwise forming functions of the intensities in the different wavelength bands. Since the imaging of the different wavelength bands is truly simultaneous, false results due to that images in different wavelength bands are detected at different times will be avoided. The present invention is to utilize deviating prisms to achieve the multiple images. Such prisms makes it possible to use commercially available camera optics for the image production which gives the advantages: faster, less bulky, easy to find commercially and cheaper. A telescope is best suited for imaging distant objects, the prism solution produces good images also of close objects which is of importance when used in the medical field.

Description

MULTI-COLOR FLUORESCENCE IMAGING UTILIZING DEVIATIONS IN PRISMS

Through previous patents (e.g. WO 86/02730), a device for simultaneous imaging of fluorescence in several wavelength bands is known. One of the purposes with the device is to enhance differences between differently fluorescing parts of the object under investigation by pointwise forming functions of the intensities in the different wavelength bands. An important advantage with the device, in contrast to a system where the different wavelength bands would be imaged consecutively, is that it allows moving objects to be studied. Since the imaging of the different wavelength bands is truly simultaneous, false results due to that images in different wavelength bands are detected at different times will be avoided.

In the patent named above, the image splitting is brought about by means of a mirror telescope with one of the mirrors cut. By replacing that solution with deviating prisms the mirror telescope can be avoided and the images can be produced by means of commercially available camera optics. Thus the optics becomes faster, of higher quality and less expensive.

The purpose of the present invention is to utilize deviating prisms to achieve the multiple images. Such prisms makes it possible to use commercially available camera optics for the image production which gives all the advantages mentioned above: It is easier to find a fast camera lens than a fast mirror telescope, and it is much cheaper, since camera lenses are produced in vast numbers. Because of this large production, much design effort has been put into the lenses and images produced with this optics are generally of high quality. It should also be noted that while a telescope is best suited for imaging distant objects, the prism solution produces good images also of close objects.

Applications of this invention include medical imaging with fiber bundles used to transmit images. Small optic distances are often desirable in these contexts. The invention is outlined in Fig. 1. A light source (1), preferably emitting light in the blue, violet or ultra-violet wavelength range, illuminates the object (2) to be studied. The emitted fluorescence light is deviated in prisms (3) as mentioned above and filters are placed in the respective beam paths. Images are produced by means of a lens (4) on a detector (5). Thus multiple images of the object in the desired wavelength bands have been obtained. The recording is controlled from a computer (7), which also carries out the subsequent image processing (6).

The light source may be a continuously working or pulsed laser, e.g. a nitrogen or an excimer laser, or a frequency-doubled alexandrite or Ti: Sapphire laser, or a lamp, the light of which is filtered to the desired wavelength range. The lamp may be a continuous lamp or a flashlamp. The prisms can either all be made in one piece or be separate ones and they may be manufactured in any optics workshop. The lens may be any commercially available camera lens and the detector a CCD camera, equipped with an image intensifier if so needed. The device recording the images can be any ordinary frame grabber that digitizes the video signal and the computer a personal computer like an IBM PC 386.

Claims

CLAIMS:

1. A fluorescence imaging system comprising a light source for irradiating an object, an optical system with a beam-splitting arrangement such that multiple images of the fluorescent object are created, optical filters for the different images, detector means to generate a respective signal for each image point and a recording and computing unit for the recording of said fluorescence radiation in a plurality of wavelength bands and executing a mathematical and/or logic operation on signals on the same image point corresponding to one and the same point on the object, therewith to obtain an expression for a weighted signal value and to produce an image of the object from the weighted signal values for the different points of the object; said beam-splitting arrangement being realized by deviations in prisms.

2. A fluorescence imaging system according to Claim 1, characterized in that the prisms are manufactured as one unit.

3. A fluorescence imaging system according to Claim 1 or 2, characterized in that the detector is constituted by a CCD camera or a an image intensified CCD camera.

4. A fluorescence imaging system according to Claim 1, 2, 3, characterized in that the object illumination is carried out by means of an optical fiber.