International Workshop on Medical Ultrasound Tomography

Ultrasound imaging from reflection data

Nov 1, 2017, 9:50 AM

20m

Lecture Hall

Oral Main Track Session 1:Imaging and inversion I

Speaker

Frank Natterer (University of Münster)

Description

When only reflection data are available, imaging with the wave equation is much more difficult then in the presence of transmission measurements. This is because reflection data are spectrally incomplete due to fact that frequencies close to zero can not be used. In the talk we describe the mathematical problem and suggest a numerical method of data completion that generates the missing low frequency data by a purely mathematical procedure.

(3) Results

We demonstrate by numerical simulations using a breast phantom patterned after the Salt Lake City phantom that good pictures can be obtained with exactly the theoretically possible spatial resolution. We describe several computing techniques such as plane wave stacking and source encoding to speed up the computations. Our reconstruction algorithm is a nonlinear version of the well known ART algorithm of CT, which instead of line integrals works directly with the wave equation.

(2) Material and Methods

Our results are based on numerical simulations using data generated by the acoustic wave equation. We model acoustic mammography by using a flat 2D transducer array.

(4) Discussion and Conclusion

Our presentation is purely theoretical. It is restricted to 2D and does not discuss practical aspects such as connecting materials. However it demonstrates that reasonable pictures can be obtained in spite of the spectral incompleteness of the reflection data.