Infrared and Raman Spectroscopy and Imaging of Breast Cancer - Vibrational Spectroscopy for Tissue Analysis - page 154

K-means (2) K-means (3) K-means (4)

Ward's (2) Ward's (3) Ward's (4)

Figure 5.49 (See colour insert.)
K-means and hierarchical clustering (Ward's method) into 2, 3, and 4 clusters.

× 10 -4 K-means (2)

× 10 -4 K-means(3)

K-means(4)

× 10 -4

5 5 5

0 0 0

-5 -5 -5

-10 -10 -10

1000 1500 1000 1500 1000 1500

× 10 -4 Ward's (2) × 10 -4 Ward's (3) × 10 -4 Ward's (4)

5

5 5

0 0

0

-5

-5 -5

-10 -10

-10

1000 1500 1000 1500

1000 1500

Figure 5.50
Mean spectra for each cluster.

Fabian et al. [71,72] present some studies comparing mapping (point-by-
point) with imaging (FPA camera) for both benign and malignant breast
tumours. The samples were 7-µm slices on BaF 2 windows, and the spectra
were measured in transmission. They describe FTIR microspectroscopy as
an imaging method that uses “infrared absorbance as an intrinsic contrast
mechanism.” [71] They used hierarchical clustering (with Ward's method for