Bonn 2020 – scientific programme

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ST: Fachverband Strahlen- und Medizinphysik

ST 6: Medical Imaging

ST 6.4: Talk

Thursday, April 2, 2020, 11:45–12:00, H-HS II

Measurement of Acoustic Properties of Passive Materials for the Use in 3D Ultrasound Computer Tomography Transducers — •Julia Koppenhöfer, Martin Angerer, and Nicole Ruiter — Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

The KIT is developing a 3D Ultrasound Computer Tomography (USCT) system for the early detection of breast cancer. The USCT system consists of 128 x 18 transducers with a centre frequency of 2.2MHz. These interchangeably send and receive ultrasound (US) pulses from which a 3D model of the breast is calculated.

To optimize the future USCT device in regard to image reconstruction performance, transducers with new materials and assemblies need to be simulated before the most promising ones are built and tested. The accuracy of these simulations depends on the properties speed of sound and acoustic impedance of the materials utilized in the transducers. Literature values either do not exist or are inaccurate as having been measured for outdated compositions of the material.

We measure the speed of sound of a material by placing a sample inside a water tank equipped with US emitter and receiver on opposite sides. The time lapse between sent and received signal is measured for different sample lengths and the speed of sound calculated from the slope. The density of each material is measured, and the acoustic impedance calculated from the density and speed of sound. In this talk, an overview of the 3D USCT system is given, methods to measure the speed of sound are discussed and results are presented.