Page 47 - ARNM-2-2

Advances in Radiotherapy &

Nuclear Medicine

ORIGINAL RESEARCH ARTICLE
Combining PET and Compton imaging with

edge-on CZT detectors for enhanced diagnostic
capabilities

Greyson Shoop* and Shiva Abbaszadeh

Department of Electrical and Computer Engineering, Baskin School of Engineering, University of
California, Santa Cruz, United States of America

Abstract

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 cm CZT detectors, with panel dimensions of
3
20 × 15 cm and a thickness of 4 cm. In this study, we demonstrate the increased
2
*Corresponding author:
Greyson Shoop sensitivity of our imaging system due to the detection of the Compton kinematics of
(grshoop@ucsc.edu) high-energy gammas originating from prompt-gamma-emitting isotopes. This was
achieved using Monte Carlo simulations of a prompt-gamma-emitting isotope, As,
72
Citation: Shoop G, Abbaszadeh S.
Combining PET and Compton with mean positron ranges >3 mm. Our system’s dynamic energy range, capable of
imaging with edge-on CZT detecting gammas up to 1.2 MeV, allows it to operate in a dual-mode fashion as both
detectors for enhanced diagnostic a Compton camera (CC) and standard PET. By presenting reconstructions of As,
72
capabilities. Adv Radiother Nucl
Med. 2024;2(2):3330. we highlight the absence of positron range effects in CC reconstructions compared
doi: 10.36922/arnm.3330 to PET reconstructions. In addition, we evaluate the system’s increased sensitivity
Received: March 31, 2024 resulting from its ability to detect high-energy prompt gammas.
Accepted: May 20, 2024
Keywords: Positron emission tomography/computed tomography; Compton camera;
Published Online: June 14, 2024
Positron range; Multi-isotope imaging
Copyright: © 2024 Author(s).
This is an Open-Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution, 1. Introduction
and reproduction in any medium,
provided the original work is The increasing availability of radionuclides for radiopharmaceuticals has positioned
properly cited. targeted radionuclide therapy (TRT) as a viable option for various cancer treatments,
Publisher’s Note: AccScience which has sparked significant interest in radiotheranostics, a field that combines
Publishing remains neutral with nuclear imaging with TRT to enable simultaneous non-invasive in vivo treatment and
regard to jurisdictional claims in 1-3
published maps and institutional visualization of cancerous tissue. The success of radiotheranostics procedures requires
affiliations. high-resolution imaging and dosimetry of tracers to accurately assess the delivery, dose,

Volume 2 Issue 2 (2024) 1 doi: 10.36922/arnm.3330