12-16 September 2005
University of Liverpool
Europe/Zurich timezone

Hybrid pixel detector development for medical radiography

Sep 15, 2005, 10:30 AM
University of Liverpool

University of Liverpool

Greenbank Conference Park
Board: P23
Contributed Poster Applications in Nuclear Medicine And Radiology P : Coffee and Poster Session


Prof. Robert Lewis (Monash University, Australia)


The instrumentation group within Monash Centre for Synchrotron Science (MCSS) and the Co-operative Research Centre for Biomedical Imaging Development (CRC BID) are developing detectors for medical, industrial, synchrotron and other scientific applications. A seven year project has been initiated to develop hybrid pixel detectors for medical radiography. The device will comprise an array of semiconductor diodes bonded to chips containing an array of readout pixels. Chips will be tiled to produce large area detectors, capable of energy dispersive photon counting operation at moderate spatial resolution (to 5 lp/mm), facilitating simultaneous multi-spectral image data acquisition. The read out chips provide individual data acquisition channels for each pixel. Each channel comprises a pre-amp, shaping amp, analogue- to-digital converter (ADC), histogramming memory, a controller and digital-to-analog converter (DAC) to adjust amplifier gains. The controller places data to the correct memory location and must communicate with adjacent pixels to identify and resolve multi-pixel events. Considerable challenges must be overcome to meet these design goals using current 90 nm fabrication processes. The project will investigate newer the compound semiconductor materials GaAs, CdTe, Cd0.9Zn0.1Te and HgI2, and explore methods for bonding these onto the readout chips. The rapid acquisition of multi spectral data will enable K-edge - subtraction imaging of contrast agent distribution and quantitative methods of x-ray analysis (QXRA), which delivers information about the density and composition of the sample. The principle obstacles to realising QXRA are the energy resolution and stability of the detector, the detection of scattered radiation and the limited number of photons available per channel. We present preliminary results from studies examining the design features of the hybrid pixel detector, and the feasibility for using the device for QXRA. Acknowledgements This study was supported by grants from the Australian government, department for education, science and training CRC for Biomedical Imaging Development.

Primary author

Stewart Midgley (Monash Centre for Synchrotron Science)


Prof. Robert Lewis (Monash University, Australia)

Presentation materials