Images from the dark

The Netherlands Organisation for Scientific Research has awarded two grants worth more than 700,000 euros to Delft research that should lead to better medical ultrasound scanners and chips for the observation of young galaxies.

Artist’s impression of Deshima (Delft Sron High-redshift Mapper), the chip Dr Akira Endo is working on. (Image: University of Leiden)
Artist’s impression of Deshima (Delft Sron High-redshift Mapper), the chip Dr Akira Endo is working on. (Image: University of Leiden)

One of the grants went to Dr Akira Endo, of the Kavli Institute of Nanoscience. Endo designs and builds spectrometers to study sub-millimetre waves emitted by distant, dust-obscured galaxies. Instead of using external mirrors and gratings to separate the wavelengths, the new detector he is developing carries everything onboard one superconducting chip. This allows for a multiple pixels chip that produces a 3D image of the galaxies, since the wavelength or ’colour’ is a measure for its distance (because of the red-shift). The prototype will carry only 9 pixels (spectrometers really) and concentrate on measuring the distance of galaxies. One could allow for more pixels on the chip by reducing the spectral sampling, but this is trade-off. Endo works together with Dr. Paul van der Werf of the Leiden Observatory and researchers from Sron and Groningen University.

The other grant receivers, Dr Martin Verweij and Dr Koen van Dongen of the laboratory of acoustical imaging (AS faculty), will use the funding to make more advanced medical ultrasound scanners.
“The technology for medical diagnosis and treatment is shifting from linear to non-linear ultrasound,” says Verweij. “When using non-linear ultrasound, the sound waves get deformed, and we can use this behavior to create sharper images.”
Basically what happens is that when long acoustic waves are sent into the body with high amplitude – for instance to make an echoscopic picture of the heart - these waves become distorted and waves with shorter wave lengths are created. This is advantageous, since the short wave lengths result in higher resolution pictures. An extra advantage of this technology, Verweij explains, is that the waves are deformed deep inside the body, after they have passed bones, like the rib cage. Reflecting bones – which normally hamper the picture - are therefore less of a nuisance when using this technology.

The two researchers will also use the funds to continue their work on small echoscopic catheters – the active parts of which are only a few hairs thick - that can travel through the aorta all the way to the heart. It is anticipated that non-linear ultrasound will also be used in these devices. However, “Non-linear ultrasound is still a complicated technology to combine with very small sensors,” Van Dongen concludes.