Very high frequency ultrasound beamformer for biomedical applications and non-destructive testing

Several research platforms are available for the development of ultrasound applications and algorithm designs but they are all limited by its digitalization frequency ranging up to 80 MHz for standard medical imaging. Using transducers with mid frequencies above 20 MHz for high resolution (bio-) medical imaging, small animal imaging, skin imaging or non-destructive material testing requires ultrasound devices with higher sampling rates. Based on the ultrasound research platform “DiPhAS” we realized the high frequency version of the beamformer with a digitalization rate of up to 480 MHz at all 128 channels. Each channel is built individually because no integrated circuits with multiple channels are commercially available for such a high digitalization rate. Transmission can be done with pre-flashed but customizable excitation sequences and output voltage up to 22 Vpp. The received data can be accessed as single element channel data of all 128 channels in parallel and transferred to a PC via Gigabit Ethernet or PCI-Express. Beamforming can be done on a massive parallel computing graphics processor (GPU). Online and offline software packages including closed loop control and filtering interfaces for Matlab, C++ and C# are used to process, analyze and visualize the data to characterize the beamformer. The system was set up successfully and evaluated and characterized for biomedical imaging methods using three 128 element ultrasound arrays (all designed by Fraunhofer IBMT) working at center frequencies of 35 MHz, 52 MHz and 56 MHz. The applications demonstrate the performance of the system to meet real time and signal quality demands for high frequency ultrasound imaging.