Microwave Induced Thermoacoustic Tomography Summer IV

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Microwave Induced Thermoacoustic
TomographySummer IV

• By Zaid Al-Husseini

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Sections

• Current Progress
• Wang et al. Patent Information
• Problems and Future Plans
• Experimental Design

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Current Progress

• Ordered the Panametrics 5670 Preamp and BCU-58-6W
  Cable (should be arriving on Friday)
• They will not charge the credit card if we return
  the Preamp and cable within two weeks (if we keep
  them they will be charged)
• Hooked up Transducer to Oscilloscope and tried to
  create Ultrasound using Infrared light, banging
  on the tableetc, all attempts were fruitless and
  provided no form of ultrasound waves.
• The Preamplifier we received from Kip is useless.
• We called HP and We were successful in Connecting
  the Oscilloscope to the Computerthere are three
  methods (C, Labview and using a sample program
  that is online)
• We downloaded the program and tested it the
  program is able to capture waveforms and record
  data that is on the oscilloscope screen at a
  given time, we can increase the period and this
  will give us a longer range of data (2000 data
  points).

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Current Progress Continued

• For Current purposes (just to make sure the
  entire apparatus works), the sample program
  provided by HP should suffice (one
  transduceretc)in future experiments, better
  antennasetc, we might need to design a C
  program to control the Oscilloscope
• We tried hooking up the Oscilloscope to the
  Network Analyzer but after reading the NA manual,
  we realized it isnt possible due to the lack of
  proper connections on the back and the lack of
  need since the Network Analyzer has a built in
  time domain output which acts exactly as an
  Oscilloscope.

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Wang et al. Patent Information

• The Patent is US 20050107692 Multi-frequency
  microwave-induced thermoacoustic imaging of
  biological tissue
• The microwave pulses are swept across a range of
  microwave frequencies. As a result, the swept
  frequency microwave pulses, the tissue region
  emits a plurality of thermoacoustic signals
• Wangs previous experiments utilizing muscle and
  fat tissues oversimplified the ability to
  successfully produce thermoacoustic waves, in
  human breast tissue however, the situation is
  more complicated
• The human breast is much larger, and has an
  irregular shape if not compressed, and is covered
  with two millimeter thick skin having dielectric
  properties significantly different from normal
  breast tissue. These factors make it much more
  difficult to heat the breast effectively.

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Wang et al. Patent Contd

• To enhance the thermoacoustic imaging of the
  human breast, several efforts have been made to
  improve the performance of conventional
  thermoacoustic imaging technology. For example,
  to achieve a higher spatial resolution, an array
  with more transducers or more acoustic data
  acquisitions at a larger aperture has been
  considered. Alternatively, for a deeper microwave
  penetration, an increase of the transmitted
  microwave power, and an array of multiple
  waveguides placed radially around the breast has
  also been suggested. Other reported efforts
  include searching for a more suitable microwave
  frequency and a more effective pulse duration of
  the microwave pulses.
• A system for examining biological tissue was
  created to produce a microwave radiation for
  radiating a tissue-region with multiple microwave
  radiation pulses, the pulses swept across a range
  of microwave frequencies resulting in the
  emission of several thermoacoustic signals
  responsive to the microwave pulses. The microwave
  radiation source can be a source of ultra
  wideband signals. An acoustic transducer array
  receives the thermoacoustic signals, and provides
  electrical signals in response. An algorithm
  forms at least one image of said tissue region
  from the electrical signals.

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Problems and Future Plans

• We still need 2 more large patch antennas for the
  project
• The Wang et al. group recently received a patent
  for multi-frequency microwave induced
  thermoacoustic imaging (2 weeks ago)
• We need a power amplifier for the Microwaves,
  however we still do not know how much power is
  required ( 5kW)
• We need a divider for the Antennas
• We still need to construct the Apparatus.
• I will be leaving for home next Thursday and will
  be back July 25th.

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Experimental Design