Apparatus Figure 1 depicts the block diagram of the instrument. The wavelengths used are 780nm and 830nm. The fiber bundles are coupled to the lateral soft compression plate on one end and to the detector module on the other. The data are finally stored in a personal computer. We have chosen the R5600U-50 GaAs PMT for the breast examination due to the very attractive radiant sensitivity features.
All measurements are for one second of acquisition.
Satisfactory signal to noise ratio is obtained even at 10 cm separations and it is typically further improved by acquiring data for longer times. The measurements are from four volunteers of different age and skin color. Clinical Set-up Figure 3 shows the placement of the patient in the MR scanner. The plates are attached to the breast in such a way that it applies soft compression, minimizing movement and ensuring the full contact of the optical sources and detectors array with the breast surface. Due to the long source fibers and fiber bundles the instrument is operated in a safe distance outside the Faraday cage of the scanner where minimal magnetic field exists.