Program Information
Fast X-Ray-Induced Acoustic Computed Tomography
R Faiz*, S Tang , B Zheng , H Liu , A Zarafshani , L Xiang , Univ Oklahoma, Norman, OK
Presentations
WE-F-708-5 (Wednesday, August 2, 2017) 1:45 PM - 3:45 PM Room: 708
Purpose: X-ray-induced Acoustic Computed Tomography (XACT) as a new imaging modality takes advantages of high sensitivity to X-ray absorption and high ultrasonic resolution in a single modality. The objective is to attain faster approach of collecting imaging dynamic information by using the principle of XACT using 128 elements ultrasound transducer ring array.
Methods: Instead of using a single transducer of low frequency to collect XA signal, our new imaging system uses a 5 MHz ring-array with 128-elements ultrasound transducer formed into a full-circular aperture. This XACT imaging system addressed the issue of longer scanning time and using multiple X-ray pulses by introducing a parallel data receiver of 128-channel pre-amplifier and a 128-channel data acquisition module which provides fast XA signal acquisition and full tomographic imaging at a faster speed. System was set-up to develop a trigger system for synchronizing the XACT data acquisition by using the scintillator/collimator combination, a photodiode, an amplifier, and a function generator to convert the ultrashort X-ray pulse to standard TTL output. A pulsed laser was used to calibrate the ultrasound array and data receiver which later was replaced by the X-ray tube. The University of Oklahoma (OU) logo was made using lead sheets which were embedded into the phantom and placed 40mm under the X-ray window. XA signals from all 128-channels then processed offline for reconstruction of an XACT-image with two-dimensional filtered back-projection algorithm.
Results: The contour of the logo was clearly visible. The external contour of the logo is more prominent than the inner contour. The full-width-at-half-maximum was measured to be 138um which is the spatial resolution of the image
Conclusion: This tested XACT system provides full tomographic imaging capability at speed up-to 25 fps and 138µm resolutions. The proposed methodology has potential for dynamic imaging of physiological activity and for noninvasive clinical diagnosis.
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