Verasonics is continuously striving to provide customers around the globe with solutions that help them explore and advance the science of ultrasonics. With Vantage Research Ultrasound systems, users can develop innovative research algorithms and development protocols in an efficient manner. For example, the Verasonics Research Ultrasound Simulator enables Vantage users to perform verification of custom programming, including acquisition sequences and data processing techniques, and can be utilized with or without the system hardware present. Additionally, the Simulator can improve research lab efficiencies by allowing staff to program the Vantage system, and even obtain training, without using the actual system.
Regev Cohen, Faculty of Electrical Engineering from Technion –Israel Institute of Technology said, “The Vantage system has changed completely the way our lab performs research and how we educate undergraduate students. The software interface is simple, flexible and facilitates the development of exploratory algorithms. By using multiple off-line Verasonics Research Ultrasound Simulators, our researchers can work in parallel, each focusing on a certain aspect of the study. Then, all parts can be easily integrated to create the desired complete imaging sequence. Furthermore, the transition from simulation to real-time application often does not require any modification in contrast to other simulators we previously used. This smooth transition has led to a dramatic reduction in our development time and has transformed the way we conduct clinical experiments by minimizing our dependence on commercial companies.”
The Verasonics Research Ultrasound Simulator emulates the sequence ultrasound acquisition functions of the hardware off-line by writing RF data to the same memory locations that the hardware system would use if active. This allows all processing functions to operate on the simulated data in the same manner as if the data was acquired by running the hardware acquisition sequence.
Five simulation licenses are included with each Vantage system purchase, allowing sequence programs to be developed on stand-alone lab computers including laptops. This facilitates sharing of a single hardware system among multiple users who can develop their programs independently and test scripts using the Verasonics Research Ultrasound Simulator. When a user sequence program is optimized using “Simulate Mode,” users can feel assured that it will likely perform properly with the hardware.
“Until now, our team has used the Verasonics Research Ultrasound Simulator to teach ultrasound imaging to our students,” said Marc Goueygou, Associate Professor of Ecole Centrale de Lille in France. “Since our lab has only a single Vantage Research Ultrasound system and we have over 30 students, the simulation software is essential for getting the team well trained on the technology in a convenient manner. What I like most is that the Verasonics Research Ultrasound Simulator has exactly the same functionalities as the Vantage software and hardware. Once you train yourself and understand how to work with the Verasonics Research Ultrasound Simulator software, there’s no additional training required once you begin working with the hardware.”
How the Verasonics Research Ultrasound Simulator Works
The Verasonics Research Ultrasound Simulator simulates echo returns from a collection of point targets with specified reflectivity. It assumes a linear model where the signals from each of the transmitting elements are returned by a media point target that can be summed at each receiving element to obtain the point target’s contribution. The transmit waveform is simulated using the user’s waveform definition with knowledge of the transducer’s bandwidth or impulse response, and weighted by the transmit apodization function and also the element’s directivity function, using the angle of the element’s normal to a given point target. The signal from a point target at a receiving element is similarly weighted for apodization and directivity, and attenuated based on the path length from the transmitting element to the receiving element. The processing of all the user defined media points generate digital RF waveforms for each receive channel, sampled at the rate chosen by the user. These waveforms can then be processed by Verasonics’ pixel oriented image reconstruction or user defined functions.
While the Verasonics Research Ultrasound Simulator’s primary aim is designed to verify the programming of user defined acquisition sequences and processing, it can also be used to investigate the use of various transmit methods and acquisition protocols as they interact with media targets. A large variety of media models can be constructed using aggregates of weighted media points. Simple models may consist of a collection of point targets arranged in geometrical patterns that can be used to access spatial resolution of the scanning method. More complex models may use large numbers of point scatterers to simulate speckle or physiological structures. Each point scatterer can have its own reflectivity coefficient. Media points can also be moved or re-defined at specific points in a sequence by invoking a user supplied media function. This allows simulation of blood flow velocity for accessing Doppler scanning methods.
The Verasonics Research Ultrasound Simulator can also be used to simulate conditions that are not supported by the hardware system itself. For example, a custom transducer with up to 1024 elements and operating at a high frequency could be simulated to assess its imaging performance prior to actual construction of the transducer. Different element distributions could be assessed, including sparse aperture arrangements.