Challenge Numerical beam simulation techniques are used to predict the location, shape and size of the beam’s focal zone. Fast and accurate prediction of this pattern will help in control and guidance of the MRgFUS treatment.

Current Techniques The techniques used for beam simulations were either too simplistic (assuming tissue to be of only one tissue type) or had long calculation times (~80 hrs for calculating one beam pattern). Designing patient-specific treatment plans, where multiple treatment options were optimized, would not be possible without a fast and accurate beam simulation algorithm.

Method The hybrid angular spectrum (HAS) technique developed can model linear wave propagation in inhomogeneous media, including varying attenuation, and the irregular geometries of the human body.  Figure above compares the beam patterns calculated using the HAS technique with a gold standard Finite Difference Time Domain (FDTD) technique for a segmented breast model, and finds that both result in essentially the same beam pattern (rms error <2%), with the HAS technique reducing the calculation time by more than two orders of magnitude. 

Awards for This Work

2013- Highly Cited Article IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Ultrasound Beam Simulations in Inhomogeneous Tissue Geometries Using the Hybrid Angular Spectrum Method, November

2013- Editor’s Selection of Highly Cited Articles in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, July

2011-Finalist Graduate Student Paper Award, International Society of Therapeutic Ultrasound

Published Results

U Vyas, DA Christensen, “Ultrasound beam simulation in inhomogeneous tissue geometries using the hybrid angular spectrum method”, Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on, 59 (6): 1093-100, 2012

U Vyas, DA Christensen, “Ultrasound beam propagation using the hybrid angular spectrum method”, Engineering in Medicine and Biology Society, 2008