Title :
A multichannel, high linearity current digitizer for digital subtraction angiography
Author :
Nakamura, M. ; Katz, J.E. ; Thompson, A.C.
Author_Institution :
Lawrence Berkeley Lab., Berkeley, CA, USA
Abstract :
An experiment studying the application of synchrotron radiation for transvenous coronary angiography requires special electronics to read out a 600-element Si(Li) detector. To obtain high image quality, the electronic system must digitize the current in all 600 elements every 2 ms with a dynamic range of 40000 and a maximum nonlinearity of 0.02%. Each channel of electronics contains a current-to-voltage amplifier with computer-controlled gain and offset followed by a voltage-to-frequency converter used in the reciprocal counting mode. A high-speed digital readout method using a lookup table, digital multiplier and direct memory interface was developed. The entire system has been designed to have a low cost per channel and to be easily expanded by 1200 signal channels.<>
Keywords :
biomedical electronics; diagnostic radiography; 600-element Si(Li) detector; Si:Li; computer-controlled gain; current-to-voltage amplifier; digital multiplier; digital subtraction angiography; direct memory interface; high linearity current digitizer; high-speed digital readout method; lookup table; low cost per channel; multichannel; reciprocal counting mode; synchrotron radiation; voltage-to-frequency converter; Angiography; Costs; Dynamic range; Image quality; Linearity; Radiation detectors; Signal design; Synchrotron radiation; Table lookup; Voltage;
Journal_Title :
Nuclear Science, IEEE Transactions on
