Radiant energy – Luminophor irradiation – With ultraviolet source
Patent
1990-11-28
1992-05-19
Hannaher, Constantine
Radiant energy
Luminophor irradiation
With ultraviolet source
128633, 128634, G01N 2164
Patent
active
051151375
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention regards improved detection of properties of tissue by means of induced fluorescence.
DESCRIPTION OF THE RELATED ART
It is known from e.g. U.S. Pat. Nos. 4,682,594 and 4,785,806, hereby included by reference, to introduce an optical fiber into a blood vessel, e.g. an artery, irradiate with laser light and sense the induced fluorescent light. It is then possible to detect atherosclerotic plaque, which can then be destroyed and removed by irradiating with high-power laser energy through the same optical fiber. The mentioned patents disclose the means for exciting, spectral analysis and high-power irradiation, including beam-splitters, coupling means and laser devices.
In EP-A-0 199 767 (which corresponds to U.S. Pat. No. 4,786,813), there is described an imaging fluorescence detecting device where a sample irradiated with an excitation wavelength is imaged through a beam-split device into a plurality of images, the images being filtered before hitting a matrix detector (CCD detector). For each image, a set of corresponding pixel intensity values is obtained, which can be arithmetically treated to obtain combined pixel values. The combined pixel values are used to create an image with improved contrast.
For fluorescence study of tissue, the fluorescent behavior of different tissues is used. In some cases, contrast may be enhanced by administering substances like hematoporphyrin derivates. A disadvantage therewith is that the patient may be hypersensitized to sunlight for extended periods, and it is thus an object of the invention to increase the detection contrast in order to diminish the necessary administering dose.
SUMMARY OF THE INVENTION
It is a general object of the invention to enable maximum contrast in fluorescence detection.
It is also an object of the present invention to improve the recognition possibilities in in vivo diagnosis of various states and variations of tissue, for example for detecting atherosclerotic plaque and various malignant tumours. It is a further object to improve treatment possibilities when removing or destroying tissue by irradiation, by means of improved possibility of study before, during and after treatment. A further object is to enable avoidance of destruction of tissue which should be left unharmed.
It is a particular object of the invention to enable detection even in the presence of blood. Blood present as an absorbent will act as a differential absorber of fluorescent radiation, destroying the contrast obtainable, severely distorting the diagnostic information. With the present invention, it is possible to substantially eliminate the influence of this disturbance factor.
According to an important aspect of the invention, the objects of the invention are attained by a combination of laser light source means for fluorescence excitation, a light detector, a light conductor like an optical fiber, coupling means for entering laser light into one end of the light conductor and for taking out light therefrom into the detector, and diagnostic means coupled to the detector, which enable the study of fluorescent light in a plurality of spectral interval channels and the comparison of the channels. This combination may be suitably completed by means for irradiation with high power through the same optical fiber, such that e.g. destruction and removal can be combined with successive recognition steps, such that the removal can be under control. The same laser may be used for both diagnostics and irradiation with high power, if the laser energy is adjusted accordingly.
According to another aspect of the invention, the system may be enlarged into an imaging system, whereby a multiple pixel system enables two-dimensional imaging, whereby for each pixel a signal is obtained for a plurality of spectral fluorescence intervals.
In this disclosure, spectral fluorescence intervals are meant to comprise both intervals in wavelength and intervals in time. In the latter case, the radiation which induces fluorescence has the form of short p
REFERENCES:
patent: 4682594 (1987-07-01), Mok
patent: 4718417 (1988-01-01), Kittrell et al.
patent: 4768513 (1988-09-01), Suzuki
patent: 4785806 (1988-11-01), Deckelbaum
patent: 4786813 (1988-11-01), Svanberg et al.
Anon., "A New Instrument for Rapid Measurement of Blood Oxygen Saturation and Hb Concentration", Bio-Medical Engineering (GB), vol. 5, No. 11 (Nov. 1970) pp. 549-552.
Andersson-Engels Stefan
Johansson Jonas
Stenram Unne
Svanberg Katarina
Svanberg Sune
Hannaher Constantine
Spectraphos AB
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