The Twente Photoacoustic Mammoscope 2: 3D vascular network visualization

We present the Twente Photoacoustic Mammoscope 2 ( PAM 2) based on a 3D tomographic geometry. A functional optical contrast map of breast vascularization can be obtained in a noninvasive, radiation-free and painless manner. A woman lies prone on a bed with one breast pendant in an imaging tank with water, where 12 curved ultrasound arrays are mounted. Each array extends from chest wall towards the nipple following the contour of the pendant breast, and carries 32 detector elements. The detectors' center frequency is 1 MHz. The breast is illuminated from multiple directions: the ventral side of the breast from the bottom and the areas close to the chest wall from the sides. The excitation wavelengths are 755 nm and 1064 nm. By rotating the imaging tank in between measurements, multiple projections can be obtained, providing a 3D image of the breast after reconstruction by means of a filtered backprojection. So far, breasts of healthy volunteers were imaged. Three-dimensional images of the breast contour, the nipple and blood vessel networks within the breast could be observed with high contrast and unprecedented detail.