Increased count-rate performance and dose efficiency for silicon photon-counting detectors for full-field CT using an ASIC with adjustable shaping time

Christel Sundberg; Mats Persson; Andreas Ehliar; Martin Sjölin; Jacob Wikner; Mats Danielsson

doi:10.1117/12.2512826

1 March 2019 Increased count-rate performance and dose efficiency for silicon photon-counting detectors for full-field CT using an ASIC with adjustable shaping time

Christel Sundberg, Mats Persson, Andreas Ehliar, Martin Sjölin, Jacob Wikner, Mats Danielsson

Author Affiliations +

Proceedings Volume 10948, Medical Imaging 2019: Physics of Medical Imaging; 109481W (2019) https://doi.org/10.1117/12.2512826
Event: SPIE Medical Imaging, 2019, San Diego, California, United States

Abstract

Photon-counting silicon strip detectors are attracting interest for use in next generation CT scanners. For silicon detectors, a low noise floor is necessary to obtain a good dose efficiency. A low noise floor can be achieved by having a filter with a long shaping time in the readout electronics. This also increases the pulse length, resulting in a long deadtime and thereby a degraded count-rate performance. However, as the flux typically varies greatly during a CT scan, a high count-rate capability is not required for all projection lines. It would therefore be desirable to use more than one shaping time within a single scan. To evaluate the potential benefit of using more than one shaping time, it is of interest to characterize the relation between the shaping time, the noise, and the resulting pulse shape. In this work we present noise and pulse shape measurements on a photon-counting detector with two different shaping times along with a complementary simulation model of the readout electronics. We show that increasing the shaping time from 28.1 ns to 39.4 ns decreases the noise and increases the signal-to-noise ratio (SNR) with 6.5% at low count rates and we also present pulse shapes for each shaping time as measured at a synchrotron source. Our results demonstrate that the shaping time plays an important role in optimizing the dose efficiency in a photon-counting x-ray detector.

Conference Presentation

Citation Download Citation

Christel Sundberg, Mats Persson, Andreas Ehliar, Martin Sjölin, Jacob Wikner, and Mats Danielsson "Increased count-rate performance and dose efficiency for silicon photon-counting detectors for full-field CT using an ASIC with adjustable shaping time", Proc. SPIE 10948, Medical Imaging 2019: Physics of Medical Imaging, 109481W (1 March 2019); https://doi.org/10.1117/12.2512826

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available