AccScience Publishing / ARNM / Volume 2 / Issue 2 / DOI: 10.36922/arnm.3330

Combining PET and Compton imaging with edge-on CZT detectors for enhanced diagnostic capabilities

Greyson Shoop1* Shiva Abbaszadeh1
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1 Department of Electrical and Computer Engineering, Baskin School of Engineering, University of California, Santa Cruz, United States of America
Submitted: 31 March 2024 | Accepted: 20 May 2024 | Published: 14 June 2024
© 2024 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( )

The key metrics for positron emission tomography (PET) imaging devices include the capability to capture the maximum available amount of annihilation photon information while generating high-quality images of the radiation distribution. This capability carries clinical implications by reducing scanning time for imaging, thus reducing radiation exposure for patients. However, imaging quality is degraded by positron range effects and the non-collinearity of positron annihilation photons. Utilizing an edge-on configuration of cadmium zinc telluride (CZT) detector crystals offers a potential solution to increase PET sensitivity. The high cross-section of CZT and its capacity to detect both 511 keV annihilation gammas and high-energy prompt gammas, along with multiple photon interaction events, contribute to this increased sensitivity. In this study, we propose a dual-panel edge-on CZT detector system comprised of 4 × 4 × 0.5 cm3 CZT detectors, with panel dimensions of 20 × 15 cm2 and a thickness of 4 cm. In this study, we demonstrate the increased sensitivity of our imaging system due to the detection of the Compton kinematics of high-energy gammas originating from prompt-gamma-emitting isotopes. This was achieved using Monte Carlo simulations of a prompt-gamma-emitting isotope,72As, with mean positron ranges >3 mm. Our system’s dynamic energy range, capable of detecting gammas up to 1.2 MeV, allows it to operate in a dual-mode fashion as both a Compton camera (CC) and standard PET. By presenting reconstructions of 72As, we highlight the absence of positron range effects in CC reconstructions compared to PET reconstructions. In addition, we evaluate the system’s increased sensitivity resulting from its ability to detect high-energy prompt gammas.

Positron emission tomography/computed tomography
Compton camera
Positron range
Multi-isotope imaging
This study was carried out with the support of the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under award numbers R01EB028091 and UG3EB034686.
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Conflict of interest
The authors declare that they have no competing interests.
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