Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-07-02
2003-06-24
Walberg, Teresa (Department: 3742)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
Reexamination Certificate
active
06584342
ABSTRACT:
FIELD OF TECHNOLOGY
This invention relates to medicine and, more particularly, to contact-free clinical diagnostics of proliferation areas in biological tissues and their localisation areas in vivo in a live organism on the basis of endogenous porphyrin fluorescence.
PREVIOUS LEVEL OF TECHNOLOGY
Both the known and the proposed proliferation area diagnostics methods are based on the ability of porphyrins to be localised selectively in proliferating tissues (The Big Medical Encyclopaedia, RU, Moscow, Sovetskaya Entsiklopedia Publishers, 1983, Volume 20, Page 349)
The known proliferation area diagnostics methods in oncology are the introduction of exogenous porphyrins to a patient (Photodynamic Therapy and Fluorescent Diagnostics of Malignant Tumours with the Use of Photogem Preparation, V.I. Chissov et al., Khirurgiya (Surgery), No. 12, 1994, p. 3-6; Clinical Fluorescent Tumour Diagnostics with Photosensitinogen Photogem, V.I. Chisov et al. Khirurgia (Surgery), No. 5, 1995, p. 37-41; (see also references in those articles) or the introduction of the preparations that stimulate active generation of endogenous porphyrins in a patient's organism (Pharmacokinetic of Endogenous Porphyrins Induced by 5-Aminolevulinic Acid as Observed by Means of Laser Induced Fluorescence from Several Organs of Tumour-Bearing Mice, Ronald Sroka, Reinhold Baugartner, Wolfgang Beyer, Liebwin Gossner, Tarek Sassy, Susanne Stocker., BIOS'95, 4-10 February. 1995, SPIE Proc. Vol. 2387, pp. 22-29) and, after some time, sufficient for selective re-distribution of the introduced exogenous porphyrins in tissues or stimulation of the generation and re-distribution of endogenous porphyrins, consecutive irradiation of small segments of the surface of the tissue under examination with the wave length which falls into the porphyrin fluorescence excitation band, with the recording of the fluorescence band simultaneously to that.
The main disadvantage of these diagnostics methods is their invasiveness, that is, the need for the introduction to a patient of either exogenous porphyrins or the substances which stimulate active generation of endogenous porphyrins in the organism. Increase in the content of porphyrins in the organism results in all negative developments typical of porphyria, such as, porphyrin exchange disfunction, including significant increase in photosensitivity of the organism. In this connection the given methods cannot be used in primary diagnostic examination, particularly in case of public preventive monitoring of the population.
The disadvantages of the indicated diagnostics methods also include their low performance caused first of all by quite a long period of time required for the selective re-distribution of the introduced exogenous porphyrins in tissues or the stimulation of the generation and re-distribution of endogenous porphyrins. Besides, the indicated methods record fluorescence bands which implies consecutive analysis of the tissue under examination from one point to another. Apart from the optic properties of the tissue proper, the size of a point, that is the area of tissue being examined at a given time, is also determined by the apertures of the radiation which induces fluorescence and the optical fibres which receive the fluorescent response and the location of their front-sides in relation to the tissue under examination. This results in low spatial resolution and poor reproducibility of the measurement results for the given methods. If it is necessary to examine big areas of various organs, skin etc., the probability of “blanks”, that is, the segments of the tissue under diagnostics that escape examination, is high. Besides, a disadvantage of the given methods is that it is difficult to document the location of proliferation areas and their localisation boundaries.
A known cancer identification method (Tumor detection in HpD-sensitized mice with fluorescence lifetime imaging, R. Cubeddu, G. Canti, A. Pifferi, P. Taroni, and G. Valentini, SPIE Proc. Vol, 2972, pp. 148-153) is the introduction of an exogenous derivative of hematoporphyrin and after some time, sufficient for its selective re-distribution in tissues, the exposure of the tissue under examination to short radiation pulses which induce fluorescence of the hematoporphyrin derivative with the wave length of 405 nm and the recording of the fluorescent image with time delay in relation to the generating radiation pulse so as to identify only the fluorescent response of the substance to be identified.
The disadvantages of this method include its invasiveness caused by the need for introducing exogenous fluorophore, as well as the complexity, high cost and relatively low resolution of the equipment required for producing the image with a millimicrosecond time delay in relation to the pulse of the radiation which induces fluorescence.
A known method of the diagnostics of affected tissues (Mechanisms of ratio fluorescence imaging of diseased tissue, Jianan Qu, Calum MacAulay, Stephen Lam and Branko Palcic, SPIE Proc. Vol. 2387, pp. 71-79), is the irradiation of the tissue segment under examination inducing endogenous fluorophores fluorescence with the wave length of 442 nm and the recording of two fluorescent images of the same tissue segment at the wave lengths of 500 nm and 630 nm. Then the ratio between two fluorescent images produced in the red and in the green wave length bands is taken, and the degree of effect on the tissue is determined by this ratio, if it exceeds a certain value.
The disadvantage of this method is relatively low sensitivity which dictates the need for using expensive cameras which brightness amplifiers. This is caused first of all by the fact that the blue radiation (442 nm) penetrates the tissue to quite insignificant depth and, respectively, can induce the fluorescence of only the fluorophores located close to the surface. Thus, it is difficult to carry out the diagnostics of defects under the surface. The optical properties of biological tissues in the blue (442 nm), green (500 nm) and red (630 nm) spectral bands are different to a significant extent and can vary from one patient to another which results in the need for using special algorithms for processing diagnostic information. Besides, railcar with the wave length of 442 nm falls into the band which induces the fluorescence of a whole range of endogenous fluorophores, such as collagen, elastin, porphyrins and their complexes with proteins, etc. Also, the concentration of porphyrins and their fluorescing complexes with proteins is frequently significantly lower than the concentration of other fluorophores. The fluorescence bands of various endogenous fluorophores are quite broad and partially overlap, therefore it is difficult to differentiate between them in case of their simultaneous excitation. Fluorescence of the fluorophores the concentration and distribution of which in tissues do not provide the required information regarding tissue condition is a confusing noise factor which distorts the informative signal.
A known method of detecting skin anomalies (Method of detecting anomalies of the skin, more particularly melanomae, and apparatus for carrying out the method, Gerhard Martens, Erhard P. H. Gunzel, U.S. Pat. No. 5,363,854, Nov. 15, 1994) is as follows: a skin segment under examination is irradiated in the ultraviolet spectrum band; the fluorescent image is recorded, and then the same skin segment is exposed to visible light, and the reference image of the same skin segment is recorded as seen in the visible band. Then a third image is produced where the brightness of each point is equal to the ratio between the brightness values of the first two images in the corresponding points. Skin segment anomalies are determined by brightness distribution in the third image.
The disadvantage of this method is its low sensitivity caused by the fact that wide band ultraviolet radiation induces the fluorescence of virtually all the fluorophores existing in the tissue under examination. It is possible to single out the fluorescent signa
Stakhanov Mikhail L.
Trushin Alexei I.
Vinogradov Alexandr V.
Notaro & Michalos P.C.
Robinson Daniel
Walberg Teresa
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