Ultrasound mammograph for breast lobe inspection
Résumé
Ultrasound Tomography (UT) has proved effective for soft-tissue (breast, liver, testicles...) characterization; it reduces also the operator-dependency observed in echography. A half-ring transducer array was designed based on the breast anatomy, to obtain reflectivity images of the ductolobular structures using tomographic reconstruction procedures. These procedures are suited to broadband data acquired in scattering configurations while the heterogeneous objects (Born approximation) are probed by spherical waves. Dedicated "elliptical" Fourier transform pair has been derived to solve the near-field inverse problem. Ultrasounds signal are acquired using a 3-MHz transducer array which comprises 1024 elements set, in a 190-degree circular arc with a radius of 100 mm. Arbitrary waveforms are synthesized to improve the signal-to-noise ratio (pulse compression) and to increase the spatial resolution when working with low contrast objects. Tomographic acquisitions were performed with low contrast 2-D breast phantoms in order to compare the detection power of the mammograph with standard ultrasound images.