A method to quantitatively evaluate the performances of a radiographic detection system consists on measuring the contrast, noise and modulation transfer functions. These functions have been evaluated for a digital radiographic system based on a single photon counting pixel detector. The X ray detector is a Silicon sensor with one side segmented in a matrix of 256 by 256 square contacts with a pitch of 55 mu m. The active area is about 2 cm(2). The sensor is connected to the Medipix2 read-out chip by bump-bonding. As X ray source we used a tube for general radiography. To reproduce the conditions of a radiographic examination a 4 cm thick Incite block positioned above the detector has been used to simulate a tissue sample. To study the Contrast Transfer Function we have measured the contrast of I mm thick lead slab with respect to the background. To evaluate the scattering contribution from the lucite, the measurements have been performed with and without a collimator placed at the beam exit. To assess the efficiency and noise transfer properties, we have measured the Detective Quantum Efficiency (DQE) of the detector as a function of the tube voltage. The Modulation Transfer Function has been measured applying the slit method for different conditions of tube voltage and energy threshold.
Bisogni, M.G., Carpentieri, C., Delogu, P., Fantacci, M.E., Novelli, M., Quattrocchi, M., et al. (2005). Characterization of a single photon counting imaging system by the transfer functions analysis. In IEEE CONFERENCE RECORD - NUCLEAR SCIENCE SYMPOSIUM & MEDICAL IMAGING CONFERENCE. [altro titolo: MEDICAL IMAGING CONFERENCE.] E212979 - issn: 1082-3654 (attiva dal 1994) Collana (pp.2984-2988). New York : IEEE [10.1109/NSSMIC.2005.1596958].
Characterization of a single photon counting imaging system by the transfer functions analysis
Delogu, P.;
2005-01-01
Abstract
A method to quantitatively evaluate the performances of a radiographic detection system consists on measuring the contrast, noise and modulation transfer functions. These functions have been evaluated for a digital radiographic system based on a single photon counting pixel detector. The X ray detector is a Silicon sensor with one side segmented in a matrix of 256 by 256 square contacts with a pitch of 55 mu m. The active area is about 2 cm(2). The sensor is connected to the Medipix2 read-out chip by bump-bonding. As X ray source we used a tube for general radiography. To reproduce the conditions of a radiographic examination a 4 cm thick Incite block positioned above the detector has been used to simulate a tissue sample. To study the Contrast Transfer Function we have measured the contrast of I mm thick lead slab with respect to the background. To evaluate the scattering contribution from the lucite, the measurements have been performed with and without a collimator placed at the beam exit. To assess the efficiency and noise transfer properties, we have measured the Detective Quantum Efficiency (DQE) of the detector as a function of the tube voltage. The Modulation Transfer Function has been measured applying the slit method for different conditions of tube voltage and energy threshold.
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https://hdl.handle.net/11365/1006374
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