title: Tryptophan autofluorescence imaging of neoplasms of the human colon.
abstract: Detection of flat neoplasia is a major challenge in colorectal cancer screening, as missed lesions can lead to the development of an unexpected 'incident' cancer prior to the subsequent endoscopy. The use of a tryptophan-related autofluorescence has been reported to be increased in murine intestinal dysplasia. The emission spectra of cells isolated from human adenocarcinoma and normal mucosa of the colon were studied and showed markedly greater emission intensity from cancerous cells compared to cells obtained from the surrounding normal mucosa. A proto-type multispectral imaging system optimized for ultraviolet macroscopic imaging of tissue was used to obtain autofluorescence images of surgical specimens of colonic neoplasms and normal mucosa after resection. Fluorescence images did not display the expected greater emission from the tumor as compared to the normal mucosa, most probably due to increased optical absorption and scattering in the tumors. Increased fluorescence intensity in neoplasms was observed however, once fluorescence images were corrected using reflectance images. Tryptophan fluorescence alone may be useful in differentiating normal and cancerous cells, while in tissues its autofluorescence image divided by green reflectance may be useful in displaying neoplasms.
authors.affiliation: University of Arizona, Department of Medicine, Section of Gastroenterology, 1501 N. Campbell Avenue, PO Box 245028, Tucson, Arizona 85724-5028, USA. bbanerjee@deptofmed.arizona.edu
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Banerjee
authors.forename: Timothy
authors.initials: T
authors.lastname: Renkoski
authors.forename: Logan R
authors.initials: LR
authors.lastname: Graves
authors.forename: Nathaniel S
authors.initials: NS
authors.lastname: Rial
authors.forename: Vassiliki Liana
authors.initials: VL
authors.lastname: Tsikitis
authors.forename: Valentine
authors.initials: V
authors.lastname: Nfonsam
authors.forename: Judith
authors.initials: J
authors.lastname: Pugh
authors.forename: Piyush
authors.initials: P
authors.lastname: Tiwari
authors.forename: Hemanth
authors.initials: H
authors.lastname: Gavini
authors.forename: Urs
authors.initials: U
authors.lastname: Utzinger
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry; D000328:Adult; D003110:Colonic Neoplasms / Q000737:chemistry*; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007413:Intestinal Mucosa / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014364:Tryptophan / Q000032:analysis / Q000737:chemistry*
chemical_list: D014364:Tryptophan