Near-infrared Raman spectroscopy for in vivo detection of cervical precancers

This study evaluates the potential of near-infrared Raman spectroscopy for in vivo detection of squamous dysplasia, a precursor to cervical cancer. A pilot clinical trial was carried out at three clinical sites. Raman spectra were measured from one colposcopically normal and one abnormal area of the cervix. These sites were then biopsied and submitted for routine histologi c analysis. Twenty-four evaluable measurements were made in vivo in 13 pati ents. Cervical tissue Raman spectra contain peaks in the vicinity of 1070, 1180, 1195, 1210, 1245, 1330, 1400, 1454, 1505, 1555, 1656, and 1760 cm(-1) . The ratio of intensities at 1454 to 1656 cm(-1) is greater for squamous d ysplasia than all other tissue types, while the ratio of intensities at 133 0 to 1454 cm(-1) is lower for samples with squamous dysplasia than all othe r tissue types. A simple algorithm based on these two intensity ratios sepa rates high-grade squamous dysplasia from all others, misclassifying only on e sample. Spectra measured in vivo resemble those measured in vitro. Cervic al epithelial cells may contribute to tissue spectra at 1330 cm(-1), a regi on associated with DNA. In contrast, epithelial cells probably do not contr ibute to tissue spectra at 1454 cm(-1), a region associated with collagen a nd phospholipids.