Prospects for the diagnosis of breast cancer by noninvasive probing of calcifications using transmission Raman spectroscopy.

Breast calcifications can be found in both benign and malignant lesions, and the composition of these calcifications can indicate the possible disease state. As current practices such as mammography and histopathology examine the morphology of the specimen, they cannot reliably distinguish between the two types of calcification, which frequently are the only mammographic features that indicate the presence of a cancerous lesion. Raman spectroscopy is an optical technique capable of obtaining biochemical information of a sample in situ. We demonstrate for the first time the noninvasive recovery of Raman spectra of calcified materials buried within a chicken breast tissue slab 16 mm thick, achieved using transmission Raman spectroscopy. The spectra of both calcium hydroxyapatite (HAP) and calcium oxalate monohydrate (COM) are obtained and chemically identified. The experimental geometry and gross insensitivity of the Raman signal to the depth of the calcified lesion makes the concept potentially well suited for probing human female breasts, in conjunction with existing mammography or ultrasound, to provide complementary data in the early diagnosis of breast cancer.