University: University of Leeds
Team Members: Maksims Kuznecovs (2016)
Project Supervisor: Dr Steven Freear
Email Address: email@example.com
High Intensity Focused Ultrasound (HIFU) Driver and Characterisation System
The aim of this project was to design, build and characterise a portable, reliable high intensity focused ultrasound (HIFU) driver system.
NI LabVIEW 2014
NI LabVIEW RT
NI LabVIEW FPGA
Sonic Concepts H-102 HIFU Transducer
High-intensity focused ultrasound (HIFU) surgery allows energy to be focused deep in the body inducing non-invasive local temperature elevation that destroys the targeted tissue, while sparing the surrounding tissue. Ultrasound, transmitted from outside the body, coagulates tumour tissue at the focal point by its energy as shown below:
Figure 1. HIFU Treatment.
Modern HIFU systems are cumbersome and expensive. Typical system setup requires multiple components:
Figure 2. Typical high-intensity ultrasound system setup.
The RF Signal Generator provides a low power signal of a specific waveform (normally sinusoidal) to the RF Power Amplifier which takes the input signal and amplifies it to match power requirements of the transducer. The frequency of operation is 1.10 Mhz and delivering hundreds of watts of power.
The motivation for this project is the development of a system which is compact, reliable and cheaper than alternative solutions, making the technology more affordable and its usage more widespread.
Instead of generating a pure sine-wave which requires complex and inefficient setup, the much simpler waveform was generated:
Figure 3. Stepped Sine Wave (5 Voltage Levels).
(In HIFU systems it is crucial to control power delivered, however signal shape supplied to the transducer can vary as shown above)
An efficient switching circuit was developed from scratch. After the breadboard testing a real PCB was designed and manufactured.
Figure 4. HIFU Transducer with a driver circuitry.
NI myRIO is used to generate the five control signals with a precise timing, utilising a high speed on-board FPGA.
Timing can be adjusted at runtime using the user interface (UI) created in LabVIEW.
Figure 5. User Interface.
The developed board directly connects to the myRIO, and is ready to be used (plug and play).
Figure 6. NI myRIO connected to the developed HIFU driver circuit.
The tight integration of hardware and software created by National Instruments saved an incredible amount of time spent during the project development and allowed to focus on the actual engineering problem. As a result, a complete, complex and fully functional project has been successfully developed.
The experimental (benchmarking) setup included designed and built HIFU driver (Excitation Circuit) with a transducer connected to it and placed in the water bath. Hydrophone was used as an ultrasound receiver and placed opposite to the transducer under water.
Figure 7. Experimental (benchmarking) setup.
NI myRIO controlled the excitation (driver) circuit, oscilloscope captured the excitation and hydrophone signal at the same time. Multiple tests were performed and the analysed data led to the conclusion that the developed circuit showed reliable and safe operation with a performance of significantly more expensive setups.