High-Intensity Focused Ultrasound Therapy Array May1005 Alex Apel Stephen Rashid Justin Robinson

Need and Problem Statement Need A research tool to provide data on phase error correction in high-intensity ultrasound arrays Problem To provide a PC based interface for a user to control the phase and duration of a four channel array of ultrasound transducers Existing solutions

System Architecture PC Software Microcontroller Circuit Serial Control Logic Analog Hardware Control Logic Analog Hardware Control Logic Analog Hardware Control Logic Analog Hardware

Users and Operating Environment Researchers Advancement of ultrasound therapy technology To be used in a laboratory with a controlled environment

User Interface Inputs Phase control per channel Pulse length Start and Stop Available Output Relative phase from feedback loop

Requirements Phase Control Set phase of each channel 360º of control Duty Cycle Control 20 ms cycle time Variable between 0.01% and 1% Scalability Potential to expand system

Deliverables Computer Software A CD installer. Needs Microsoft.NET Framework (Win2000 SP4 or newer). Application provides UI with Microcontroller Board Driver Board Driver board controls multiple transducer control circuits. Driver board is manipulated via a RS232 connection to the user PC. Transducer Card (4x) Controls the Analog Power Circuits. Allows for concurrent processes. Analog Power Circuits (4x) Amplify the waveform and provide power to Transducer. End User Guide Reference on how each element of the system works. Guide to using the software.

Work Breakdown Design and Documentation Process Group influence and final decision making Diversity of knowledge allows for specialties in decision making Computer Software Primary focus area of Justin Robinson Digital Circuit and Microcontroller Software Primary focus of Alex Apel Analog Power Circuits Primary Focus of Stephan Rashid End User Guide Sum of group knowledge of the device and its functionality Group Contribution

Resource Requirements TaskHoursCost Problem Definition84$1680 Technology/Implementation Considerations/Selection79$1580 System Design77$1540 System Implementation104$2080 System Tesing82$1640 System Documentation55$1100 System Demonstration12$240 Project Reporting185$3700 Totals678$13,560 ItemCost Microcontroller Dev Board$159 H Bridge Amplifier$100 - $660 Supporting Discrete Parts$100 Total$359 - $919

Project Schedule

Risks Loss of Team Member Reduce knowledge base Lose time commitment Mitigated by effective communication and system scope scalability Loss of Transducer Needed to display results Irreplaceable, cost Emulation circuit for testing Lack of Expertise Risk posed by time restrictions May lead to poor decision making Effective use of external resources and knowledge bases

System Requirements Power 500W per Channel 0.01% to 0.1%, Max 1% Duty Cycle 20 ms Cycle Period Scalability Future system may control 500 elements Operating Frequency Maximum amplitude at 1.1 MHz Wish of 3.3 MHz Phase Control 360º of phase correction 8 bit resolution = 1.4º Allows for a 1.2 nm3 focal point

Functional Decomposition Input Relative Phase Control Signal Period Signal Duty Cycle Generation Power: 500W Feedback Generation Processing Frequency 1.1 – 3.3 MHz Adjustable Duty Cycle 20 ms Cycle Period Phase Correction Waveform Generation

System Analysis PC Software Microcontroller Circuit Serial Control Logic Analog Hardware Control Logic Analog Hardware Control Logic Analog Hardware Control Logic Analog Hardware

Input/Output Specification GUI Input Relative Transducer Phase Transducer Amplitude Signal Period Signal Duty Cycle Start/Stop Generation Output Phase Micro Transducer Output Mechanical Wave RS-232 Transducer Output Mechanical Wave Transducer Control Logic Transducer Analog Hardware Phase Correction

User Interface Specification

User PC Software GUI Transducer Input [1..n] ID Relative Phase Amplitude Global Input Signal Period Signal Duty Cycle Start/Stop Generation Misc. Save Input Data Load Input Data Transducer ID : int Relative Phase : int Amplitude : int AdjPhase() : int AdjAmplitude() : int File Storage Comm. Out In Serial Lab PC

Microcontroller Circuit Serial Interface to PC Microcontroller Storage and Correction of Waveforms System of addressing multiple transducers Assertion and Control of global time frame

Transducer Control Circuit Feedback Collection Waveform Assertion Concurrent Access

Analog Hardware Design H Bridge Controller H Bridge Power Supply Transducer Hi/Lo On/Off To Digital Phase Correction

Test Plan Unit Tests Comm. Test Integration Tests Comm. Test System Test Comm. Test PC RS-232 PC Micro RS-232 PC Micro RS-232 Hydro phone Transducer

Simulation & Modeling Identifying Needs of Generated Waveform Transducers Operate at Odd Harmonics Fourier Analysis of Proposed Waveforms P-Spice Modeling of Circuitry H-Bridge Amplifier Behavior Frequency Characteristics

Acknowledgments Dr. Timothy Bigelow Dr. Randy Geiger Texas Instruments

Questions?