Search

We have proposed an echo localization estimator which theoretically gives infinite resolution in the axial direction in ultrasonic B-mode images during 1) echo structure tracking and 2) distance measurements of distinct echoes. The performance of the estimator was evaluated using a HDI5000 (Philips Medical Systems, Bothell, WA, USA) with a 35 mm 5-12 MHz linear array transducer. The resulting pixel size in the B-mode image was 100 m. The controlled setup consisted of a small water container lined with ultrasound absorber carpet and placed on a micrometer table, a triangulation laser (M5L/2, MEL Mikroelektronik GmbH, Eching, Germany) connected to a high-performance digital multimeter HP 34401A (Agilent Technologies, USA) and a thermometer TESTO 925 (Testo AG, Germany). In each of the three measurement series the micrometer table was moved approximately 15 m in 10-12 steps. The echo localization estimator succeeded to resolve the minute movement ( 0.998; p

A polymer foil based array with 9 gold electrodes for chronic electrophysiological recordings in the CNS has been developed. A polymer, SU-8, is pattered using photolithography techniques used every day in micro fabrication. This is beneficial if the electrode would be manufactured on a large scale basis. The technique makes it easy to adapt the array to best fit the structure of interest at the time, in this study the rat cerebellar cortex. The use of SU-8 as the base of the array makes the array very flexible, hence lets it stay close to the same cells following the movement of the brain. The electrodes can then be modified with platinum black to lower the impedance of the electrode up to one order of magnitude, making us able to create smaller electrodes but keeping the low impedance necessary to get a get the signal to noise ratio required. Platinum black modified arrays were also implanted chronically and showed excellent signal recording capabilities in rat cerebellum.