[Laser-induced fluorescence (LIF) spectrum of colorectal cancer in vivo].
OBJECTIVE
To study the LIF spectrum of colorectal cancer, adenomas, chronic colitis and normal colon tissue in vivo, with special emphasis on precancerous lesions.


METHODS
A nitrogen laser (wavelength 337 nm) beam was introduced through endoscopic colonoscope and the fluorescence emission was recorded. An optical multichannel analyzer (OMA III) was used to analyze the fluorescence emission spectrum. A total of 83 patients was examined.


RESULTS
The emission spectrum of LIF recorded on colorectal cancer and normal tissue showed significant differences in intensity and shape. (1) The normal tissue had higher intensity than that of cancer tissue. (2) The main peak wavelength of cancer moved to the red. (3) The minor peak of the cancer tissue fell more slowly than that of the normal tissue. Intensity of the main peak (x1), intensity ratio of 400 to 530 nm (x2) and the integrated LIF intensity (350-600 nm) (x3) were used as parameters to obtain an equation. The sensitivity and specificity of LIF for diagnosis of colorectal cancer was 83.3% and 94.4%, respectively. In 87.1% of moderate and severe dysplastic adenomatous polyps, the fluorescence spectrum was abnormal.


CONCLUSIONS
In vivo, the LIF spectrum can be used to distinguish colorectal cancer from normal colon, especially from dysplasia. It plays an important role in the early diagnosis of colorectal cancer.
Li
J
J
Air Force General Hospital, Beijing 100036, China.
Li
S
S
Gao
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000737:chemistry* / Q000175:diagnosis; D005260:Female; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D013050:Spectrometry, Fluorescence / Q000379:methods