Realization of an pseudo-randomly sampled 3D USCT

Zapf, Michael; Hopp, Torsten; Gemmeke, H.; Angerer, Martin; Lu, Zewei; Molchanova, O. V; Rashvand, Nima; Blanco, Roberto; Steck, Petra; Leyrer, Benjamin; Tcherniakhovski, D.; Bormann, D.; Schlote-Holubek, Klaus; Ruiter, Nicole V.

doi:10.1117/12.2611705

Cited by 7 publications

(5 citation statements)

References 5 publications

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“…Two single-element or clinical array transducers could be purchased and mounted to a rotation stage to sample a virtual array [16,17], but this configuration has a large data acquisition time and so multi-element transducer arrays that fully surround the object are typically used instead. Either bowl [18] or rotating planar [19] configurations are used in 3D, but the most common design is a vertically translated 2D ring array [20,17,21], since these allow data to be collected and reconstructed in 2D slices, which is computationally efficient. The standard open-UST configuration is a 2D ring array, but its modularity also allows reconfiguration into 3D geometries.…”

Section: Array Designmentioning

confidence: 99%

See 1 more Smart Citation

open-UST: An Open-Source Ultrasound Tomography Transducer Array System

Roberts¹,

Martin²,

Brown³

et al. 2023

Preprint

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Fast imaging methods are needed to promote widespread clinical adoption of Ultrasound Tomography (UST), and more widely available UST hardware could support the experimental validation of new measurement configurations. In this work, an open-source 256-element transducer ring array was developed (morganjroberts.github.io/open-UST) and manufactured using rapid prototyping, for only £2k. Novel manufacturing techniques were used, resulting in a 1.17 • mean beam axis skew angle, a 104 µm mean element position error, and a ±13.6 µm deviation in matching layer thickness. The nominal acoustic performance was measured using hydrophone scans and watershot data, and the 61.2 dB SNR, 55.4 • opening angle, 16.3 mm beamwidth and 54% transmit-receive bandwidth (-12 dB), were found to be similar to existing systems, and compatible with full waveform inversion reconstruction methods. The inter-element variation in acoustic performance was typically <10% without using normalisation, meaning that the elements can be modelled identically during image reconstruction, removing the need for individual source definitions based on hydrophone measurements. Finally, data from a phantom experiment was successfully reconstructed. These results demonstrate that the open-UST system is accessible for users, and suitable for UST imaging research.

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Section: Array Designmentioning

confidence: 99%

“…Current UST systems have between 40 [21] and 2304 [18] transducer elements. Systems with many elements have denser sampling and higher image quality, but are complex to manufacture and require a data acquisition system (DAQ) with an equivalent channel count, or a multiplexer.…”

Section: Array Designmentioning

confidence: 99%

open-UST: An Open-Source Ultrasound Tomography Transducer Array System

Roberts¹,

Martin²,

Brown³

et al. 2023

Preprint

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“…At KIT we are developing a full 3D USCT system, 1,4 which arranges the ultrasound transducers in a hemispherical aperture. The aperture has a diameter of approximately 35 cm and is equipped with a total of 2304 transducer, each being able to act as an emitter and receiver.…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of tissue scatter characteristics using 3D ultrasound tomography

Hopp,

Maul,

Ebener

et al. 2024

Medical Imaging 2024: Ultrasonic Imaging and Tomography

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Conventional reflectivity imaging with Ultrasound Tomography (USCT) reconstructs qualitative images proportional to the magnitude of the impedance gradient. We propose a method to additionally recover the scatter characteristics for each reconstructed voxel, i.e. whether a reflection is diffuse or specular. This is achieved using a modification of 3D Synthetic Aperture Focusing Technique (SAFT). Our novel approach separates the incoming and outgoing ultrasound intensity in each voxel according to the incident direction and the direction to the receiver. To reduce memory requirements, we propose several strategies for selecting a subset of data or aggregating data to predefined directions. The reconstruction leads to five-dimensional data, from which for each voxel in 3D space, a 2D scatter map can be derived. It can be interpreted as the distribution of energy which has been introduced from a certain direction and which has been reflected into a particular direction. We validated our approach by a simulation based on the Phong reflection model and perform first reconstructions of experimental data. Using the 2D scatter maps it is possible to distinguish specular from diffuse reflections visually. Extracting first-order statistics from the 2D scatter maps for each voxel can be a means to break down the 5D information to 3D for traditional slice-based visualization. The multidimensional data provided by our method may be used in future as a biomarker for diagnosis as e.g. a plain surface of a cyst may reflect the ultrasound differently than a rough surface of a spiculated mass.

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“…After having realized a first prototype for clinical studies, 3 we recently redesigned the system by -among others -enlarging the aperture for better illumination and larger field of view, adding a new patient interface aimed at imaging up to the chest wall, a pseudo-random distribution of transducers to reduce artifacts due to the sparsity of the system, and a faster data readout. 4 In this paper we follow up on the qualitative and quantitative evaluation of the image quality of the new system called 3D USCT III. We summarize first imaging results with phantoms and present a first analysis of volunteer images.…”

Section: Introductionmentioning

confidence: 99%

First imaging results with the new generation of the KIT 3D ultrasound tomography device

Hopp

Zapf

Fernandez-Lago

et al. 2023

Medical Imaging 2023: Ultrasonic Imaging and Tomography

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Ultrasound Tomography (USCT) is an emerging technology for early breast cancer detection. At Karlsruhe Institute of Technology we recently realized a new generation of full 3D USCT device with a pseudo-randomly sampled hemispherical aperture. In this paper we summarize first imaging results with phantoms and first volunteer images. Using a gelatin phantom with PVC inclusions we evaluated transmission imaging, which showed a deviation from the ground truth of less than 5 m/s in the sound speed and 0.2 dB/cm in the attenuation for the phantom body and less than 15 m/s and 0.2 dB/cm for an inclusion with a diameter of 2.2 cm. Geometric errors are in average in the range of 0.2 cm. For reflectivity imaging we showed that the point spread function is nearly isotropic and with an average of 0.26 mm close to the theoretical predictions for the current system. While the system is still in final commissioning, the results of the phantom and volunteer imaging are very promising: after further calibration and deeper analysis with phantoms we aim at starting a clinical study.

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Realization of an pseudo-randomly sampled 3D USCT

Cited by 7 publications

References 5 publications

open-UST: An Open-Source Ultrasound Tomography Transducer Array System

open-UST: An Open-Source Ultrasound Tomography Transducer Array System

Reconstruction of tissue scatter characteristics using 3D ultrasound tomography

First imaging results with the new generation of the KIT 3D ultrasound tomography device

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