display from a software coding perspective it is expected that these switches are very easily implemented in one or two lines of code near the main entry point of the top level gpus software module the special ffbu transducer referred to supra comprises a very long array e g 15 cm long of transducer elements the ffbu transducer generally is much longer and has more elements than commonly used with gpus 100 according to a preferred embodiment field programmable gate array fpga logic is included in the ffbu transducer that provides a u201c sliding window u201d effect such that only a predetermined number of elements are active at any time along a subset of the length after obtaining one or more lines of scan data associated with the present window position the window is moved by the fpga logic responsive to commands from the ultrasound engine hardware and the process is repeated until the end of the array is reached notably the presence of a u201c sliding window u201d along the transducer length is transparent to the ultrasound engine and is handled by the timing circuitry of the fpga in combination with the software module 218 according to another preferred embodiment a pre formed gel block is provided that is specially shaped to fill in air gaps between the breast periphery and the upper and lower compressive members of an ffbu scanning device this has been found to substantially improve volumetric ultrasound data acquisition near the skinline of the breast in one preferred.