04 February 2009
Boosting scan resolution
As part of a move to increase throughput in computer tomography (CT) systems and to improve their resolution, Analog Devices has developed the ADAS1128 current to digital converter.
CT systems feature an xray source which rotates around the patient. Xrays are captured, the data converted and an animation created. Earlier CT systems used a single slice approach, but Jan-Hein Broeders, pictured, HealthCare Business Development & Application Engineer Europe for Analog Devices, said the latest CT systems were using 320 slices.
“Xrays are captured by a scintillator,” he noted, “and converted by photodiodes. The data is then fed into a front end chip.” Each slice comprises 1000 pixels, so the scale of the problem is apparent.
The ADAS1128 is a 128channel 24bit current to digital converter running at 20ksample/s. Broeders said the part has a dynamic range of 115dB and a 19bit enob.
“Users want to scan as much as possible in one rotation,” he said, “providing radiologists with better discrimination. And the part has low noise, which means the xray exposure can be minimised.”
System builders can also adjust the part to suit their requirements. “There are more than 100 full scale ranges to choose from,” Broeders noted, “and the oversampling rate can be varied.”
The ADAS1128 is supplied in a mini bga measuring 1 x 1cm.
Author
Graham Pitcher
Supporting Information
Websites
http://www.analog.com
Companies
Analog Devices
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