A rapid method for the analysis of Pap smears has been developed with the use of near-infrared spectroscopy. Spectra of Pap smears from 50 female patients including 30 with normal cells, 9 with atypical cells, and 11 with cervical cancer were measured in the near-IR region of 4000 to 10,000 cm<sup>-1</sup>. Both the original spectra and the second-derivative spectra of Pap smears were subjected to data analysis. The malignant samples displayed abnormal spectra compared with the corresponding normal cervical samples; the atypical samples have spectral features characteristic of both normal and abnormal samples. With the use of principal component analysis (PCA) and discriminant analysis, the samples were grouped in patterns that were consistent with clinical analysis. Since obtaining near-infrared spectra of human tissues is a rapid and inexpensive process, the results suggest that the near-infrared spectra of human tissues may be of diagnostic value for cancer diagnosis.
Zhengfang Ge, Chris W. Brown, and Harold J. Kisner, "Screening Pap Smears with Near-Infrared Spectroscopy," Appl. Spectrosc. 49, 432-436 (1995)