Instrumentation and clinical applications in frequency-domain optical mammography

We describe an instrument for frequency-domain light mammography (LIMA), and we present clinical results obtained on patients affected by breast cancer. This instrument uses two laser diodes emitting at 690 and 825 nm. Their intensities are modulated at a frequency of 110 MHz. The amplitude and the phase of the intensity wave are the measured quantities. The breast is slightly compressed between two glass plates and the optical signal is detected in transmission, i.e. on the opposite side of the illuminated spot of the breast. The acquisition time for a full breast image is about 3 minutes. Edge effects (that are mainly due to the breast thickness variability within the scanned area) are corrected by an algorithm of data analysis which enhances the contrast of the optical mammograms. In the clinical applications, we successfully detected 27 out of 37 malignant tumors (73%). This result shows the practical feasibility and the significant potential of frequency-domain optical mammography

Instrumentation and clinical applications in frequency-domain optical mammography

We describe an instrument for frequency-domain light mammography (LIMA), and we present clinical results obtained on patients affected by breast cancer. This instrument uses two laser diodes emitting at 690 and 825 nm. Their intensities are modulated at a frequency of 110 MHz. The amplitude and the phase of the intensity wave are the measured quantities. The breast is slightly compressed between two glass plates and the optical signal is detected in transmission, i.e. on the opposite side of the illuminated spot of the breast. The acquisition time for a full breast image is about 3 minutes. Edge effects (that are mainly due to the breast thickness variability within the scanned area) are corrected by an algorithm of data analysis which enhances the contrast of the optical mammograms. In the clinical applications, we successfully detected 27 out of 37 malignant tumors (73%). This result shows the practical feasibility and the significant potential of frequency-domain optical mammography

Frequency-domain optical mammography: edge effect corrections.

We have investigated the problem of edge effects in laser-beam transillumination scanning of the human breast. Edge effects arise from tissue thickness variability along the scanned area, and from lateral photon losses through the sides of the breast. Edge effects can be effectively corrected in frequency-domain measurements by employing a two-step procedure: (1) use of the phase information to calculate an effective tissue thickness for each pixel location; (2) application of the knowledge of tissue thickness to calculate an edge-corrected optical image from the ac signal image. The measurements were conducted with a light mammography apparatus (LIMA) designed for feasibility tests in the clinical environment. Operating in the frequency-domain (110 MHz), this instrument performs a transillumination optical scan at two wavelengths (685 and 825 nm). We applied the proposed two-step procedure to data from breast phantoms and from human breasts. The processed images provide higher contrast and detectability in optical mammography with respect to raw data breast images