Method and apparatus for displaying a tissue containing a fluorescent dye
A method is disclosed for displaying a tissue containing a fluorescent dye at least in sections. In order to reduce interference signals, it is proposed to record a first fluorescent image during an illumination phase, and a second fluorescent image during a dark phase, and to correct the first fluorescent image by subtracting the second fluorescent image and to process it subsequently to form an overall image.
1. A method for displaying a tissue containing a fluorescent dye, at least in sections, comprising:
illuminating the tissue with a first light for exciting the fluorescent dye and includes a clock frequency given by a periodic sequence of illumination phases and dark phases;
separately acquiring first fluorescent images generated during the illumination phases by excitation of the fluorescent dye, and second fluorescent images generated during the dark phases by an illumination of the tissue with a second light;
correcting the first fluorescent images by subtracting second fluorescent images corresponding thereto; and
generating overall images by superimposing on the corrected first fluorescent images corresponding native tissue images which reproduce a tissue surface, wherein a number of second fluorescent images are acquired in a fashion following one another temporally during the dark phase, and
wherein, for the purpose of producing a second fluorescent image, at least one late fluorescent image acquired during a prescribed late time interval of the dark phase is subtracted from at least one early fluorescent image acquired in relation to a prescribed early time interval.
2. The method as claimed in claim 1 , wherein the overall image is reproduced with a display frequency.
3. The method as claimed in claim 2 , wherein the clock frequency is an integral multiple of the display frequency.
4. The method as claimed in claim 2 , wherein the display frequency is 10 to 60 Hz.
5. The method as claimed in claim 2 , wherein the clock frequency is twice the display frequency.
6. The method as claimed in claim 2 , wherein the display frequency is 20 Hz.
7. The method as claimed in claim 1 , wherein the first fluorescent image is displayed in the overall image by way of a false color.
8. The method as claimed in claim 1 , wherein infrared light is used as first light.
9. The method as claimed in claim 1 , wherein an infrared light of a frequency of more than 700 nm in a near infrared region, which is an infrared light of a wavelength of more than 750 nm, is used as the first light.
10. An apparatus for displaying a tissue containing a fluorescent dye, at least in sections, comprising:
an illumination device to illuminate the tissue with a first light for exciting the fluorescent dye and includes a clock frequency given by a periodic sequence of illumination phases and dark phases;
an acquisition device to separately acquire first fluorescent images generated during the illumination phases by the excitation of the fluorescent dye, and second fluorescent images generated during the dark phases by an illumination of the tissue with a second light;
a correction device to correct the first fluorescent images by subtracting second fluorescent images corresponding thereto; and
an image generating device to generate overall images by superimposing the corrected first fluorescent images with corresponding native tissue images which reproduce a tissue surface, wherein a number of second fluorescent images can be acquired via the acquisition device in a fashion fol 1 owing one another temporally during the dark phase, and
wherein, in order to produce a second fluorescent image, a further correction device is provided to subtract at least one late fluorescent image acquired during a prescribed late time interval of the dark phase from at least one early fluorescent image acquired in relation to a prescribed early time interval.
11. The apparatus as claimed in claim 10 , further comprising: a device to generate a display frequency for reproducing the overall image.
12. The apparatus as claimed in claim 11 , wherein the excitation frequency is an integral multiple of the display frequency.
13. The apparatus as claimed in claim 10 , wherein the excitation frequency is 10 to 60 Hz.
14. The apparatus as claimed in claim 10 , further comprising:
a device to display the first fluorescent image in the overall image by means of a false color.
15. The apparatus as claimed in claim 10 , wherein the first light is infrared light.