Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2000-01-28
2003-12-16
Manuel, George (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S476000, C600S474000, C600S477000
Reexamination Certificate
active
06665556
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the examination of tissues using optical spectroscopy and relates more particularly to a method and an apparatus for examining a tissue using the spectral wing emission therefrom induced by visible to infrared photoexcitation.
Optical spectroscopy has received increasing attention over the past several years as a tool for use in examining tissues. One such application of optical spectroscopy to the examination of tissues has been in the detection of cancer and precancerous states and has involved the use of steady-state native fluorescence. For example, in U.S. Pat. No.4,930,516, inventors Alfano et al., which issued Jun. 5, 1990, and which is incorporated herein by reference, there is disclosed a method and apparatus for detecting the presence of cancerous tissue using visible luminescence. According to the aforementioned patent, the tissue to be examined is excited with a beam of monochromatic light that causes the tissue to fluoresce over a spectrum of wavelengths. The monochromatic light disclosed in the patent has a wavelength in the range of 350-500 nm. The intensity at which the excited tissue fluoresces is measured either over a spectrum or at a predetermined number of preselected wavelengths, such as at 531 nm, 522 nm and 633 nm. The patent further teaches that one can then determine the carcinomatoid status of the tissue in question by comparing the detected spectrum, one or more peak wavelengths of the detected spectrum, or a ratio or difference of particular wavelengths from the detected spectrum to standards obtained from known tissues.
Another example of the use of optical spectroscopy, particularly steady-state native fluorescence, in the detection of cancer and precancerous states is disclosed in U.S. Pat. No. 5,131,398, inventors Alfano et al., which issued Jul. 21, 1992, and which is incorporated herein by reference. In the aforementioned patent, there is disclosed a method and apparatus for distinguishing cancerous tumors and tissue from benign tumors and tissue or normal tissue using native fluorescence. According to one embodiment of said patent, the tissue to be examined is excited with a beam of monochromatic light at 300 nm. The intensity of the native fluorescence emitted from the tissue is measured at 340 nm and at 440 nm. The ratio of the two intensities is then calculated and used as a basis for determining if the tissue is cancerous as opposed to benign or normal. According to another embodiment of said patent, excitation profiles may be employed to distinguish cancerous tissue from benign or normal tissue. For example, the patent teaches that excitation spectra obtained by measuring the intensity of fluorescence at 340 nm as the excitation wavelength is varied from 220 nm to 325 nm are different for cancerous and benign breast tissues.
Other patents and publications that relate to the use of steady-state native fluorescence in the detection of cancer and precancerous states include the following: U.S. Pat. No. 5,042,494, inventor Alfano, issued Aug. 27, 1991; U.S. Pat. No. 5,413,108, inventor Alfano, issued May 9, 1995; U.S. Pat. No. 5,769,081, inventors Alfano et al., issued Jun. 23, 1998; U.S. Pat. No. 5,612,540, inventors Richards-Kortum et al., issued Mar. 18, 1997; U.S. Pat. No. 4,957,114, inventors Zeng et al., issued Sep. 18, 1990; Yang et al., “Fundamental Differences of Excitation Spectrum between Malignant and Benign Breast Tissues,”
Photochemistry and Photobiology,
66(4):518-22 (1997); Yang et al., “Excitation Spectrum of Malignant and Benign Breast Tissues: A Potential Optical Biopsy Approach,”
Lasers in the Life Sciences,
7(4):249-65 (1997); Galeotti et al., “On the Fluorescence of NAD(P)H in Whole-Cell Preparations of Tumours and Normal Tissues,”
Eur. J. Biochem.,
17:485-96 (1970); and Japanese Patent Application No. Sho-57-795, published Jul. 15, 1983, all of which are incorporated herein by reference.
In addition, it should be noted that steady-state native fluorescence has also been used to detect a number of other abnormal or disease states unrelated to cancer, such as the detection of caries in teeth (U.S. Pat. No. 4,479,499, inventor Alfano, which issued Oct. 30, 1984, and which is incorporated herein by reference) and the detection of atherosclerotic plaque in arteries (U.S. Pat. No. 4,913,142, inventors Kittrell et al., issued Apr. 3, 1990, and which is incorporated herein by reference).
Another type of technique for detecting cancer in tissues has involved the use of time-resolved fluorescence spectroscopy and is exemplified by U.S. Pat. No. 5,348,018, inventors Alfano et al., which issued Sep. 20, 1994, and U.S. Pat. No. 5,467,767, inventors Alfano et al., which issued Nov. 21, 1995, both of which are incorporated herein by reference. In, for example, the aforementioned U.S. Pat. No.5,348,018, there is disclosed a method for determining if tissue is malignant as opposed to non-malignant (i.e., benign tumor tissue, benign tissue, or normal tissue), said method comprising, in one embodiment, irradiating a human breast tissue sample with light at a wavelength of about 310 nm and measuring the time-resolved fluorescence emitted therefrom at about 340 nm. The time-resolved fluorescence profile is then compared to similar profiles obtained from known malignant and non-malignant human breast tissues. By fitting the profiles to the formula I(t)=A
1
e
(−t/&tgr;1)
+A
2
e
(−t/&tgr;2)
, one can quantify the differences between tissues of various conditions. For example, non-malignant human breast tissues exhibit a slow component (&tgr;
2
) which is less than 1.6 ns whereas malignant human breast tissues exhibit a slow component (&tgr;
2
) which is greater than 1.6 ns. In addition, non-malignant human breast tissues exhibit a ratio of fast to slow amplitudes (A
1
/A
2
) which is greater than 0.85 whereas malignant human breast tissue exhibit a ratio of fast to slow amplitudes (A
1
/A
2
) which is less than 0.6. This technique can be used with different excitation and/or emission wavelengths, and can be applied to the detection of malignancies (or other abnormal states) in tissues other than human breast tissue.
It should be noted that conventional fluorescence spectroscopic techniques of the types described above for detecting cancerous or precancerous states in tissues, whether of the steady-state variety or of the time-resolved variety, have typically involved using photoexcitation wavelengths far below 600 nm, said photoexcitation wavelengths typically residing in the range of about 300 to 500 nm.
Another type of spectroscopic technique that has been used to examine tissues has involved the use of Raman spectroscopy. One such application of Raman spectroscopy to the examination of tissues has been in the detection of cancer and is exemplified by U.S. Pat. No.5,261,410, inventors Alfano et al., which issued Nov. 16, 1993, and which is incorporated herein by reference. In the aforementioned patent, there is disclosed a method for determining if a tissue is a malignant tumor tissue, a benign tumor tissue, or a normal or benign tissue. The method is based on the discovery that, when irradiated with a beam of infrared monochromatic light, malignant tumor tissue, benign tumor tissue, and normal or benign tissue produce distinguishable Raman spectra. For human breast tissue, some salient differences in the respective Raman spectra are the presence of four Raman bands at a Raman shift of about 1078, 1300, 1445 and 1651 cm
−1
for normal or benign tissue, the presence of three Raman bands at a Raman shift of about 1240, 1445 and 1659 cm
−1
for benign tumor tissue, and the presence of two Raman bands at a Raman shift of about 1445 and 1651 cm
−1
for malignant tumor tissue. In addition, it was discovered that for human breast tissue the ratio of intensities of the Raman bands at a Raman shift of about 1445 and 1659 cm
−1
is about 1.25 for normal or benign tissue, about 0.93 for benign tumor tissue, and about 0.87 for
Alfano Robert R.
Demos Stavros G.
Zhang Gang
Cohen & Pontani, Lieberman & Pavane
Manuel George
Qaderi Runa Shah
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