Is the CZT technology the future of nuclear cardiology?
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Mount Sinai Health System, New York, NY Hartford Hospital, Hartford, CT
Received Sep 4, 2020; accepted Sep 4, 2020 doi:10.1007/s12350-020-02399-4
See related article, https://doi.org/10.10 07/s12350-020-02334-7.
The history of Nuclear Cardiology is well known, well documented, and occurred in living memory. Many of its pioneers are either still active or available to recount the imaginative first steps, the era of competition-free adoption, introduction of Tc-99m-based tracers, and acceptance and refinement of the testing protocols.1 Despite of the emergence of new non-invasive imaging methods for the detection of epicardial coronary artery disease (CAD), namely PET, stress echocardiography, and coronary CTA, SPECT imaging still remains the most often performed test for its proven diagnostic and prognostic value.2 During the last decade of the last century, stress methods were expanded by the introduction of potent coronary vasodilators (dipyridamole, adenosine, and regadenoson). The original SPECT tracer Tl-201 was more or less replaced with Tc-99m-based agents. Amazingly, the original hardware technology did not change substantially since its inception more than 50 years ago: Anger cameras consisting of NaI crystal detectors connected to an array of photo-multiplying tubes converting photons to electrical potentials underwent only minor improvements over the decades. Poor photon detection efficiency, long imaging times, QC requiring substantial resources and expertise, as well as new concerns about potential cancer hazards in the era of sky rocketing volume of external radiation diagnostic procedures, all called for new approaches.3
Reprint requests: Lane Duvall, Hartford Hospital, Hartford, CT; [email protected] J Nucl Cardiol 1071-3581/$34.00 Copyright Ó 2020 American Society of Nuclear Cardiology.
The most successful innovation available in more than a decade was the development and availability of CZT (cadmium-zinc-telluride) solid-state SPECT cameras. There are currently two commercially available models: D SPECT (Spectrum Dynamics, Caesarea, Israel) and Discovery 530c (GE Healthcare). Simultaneous acquisition (no moving parts) of the photons originating mostly from the imaged object (the myocardium) thanks to focused collimation increases the camera efficiency 5-10 times. CZT cameras allow for fast acquisition (3-5 vs 20-30 minutes), substantial tracer dose reduction (from [ 12 to 5-7 mSv per test), time savings, and simplified QC procedures.4 The performance of the two available CZT cameras is not identical. However, the advantages compared to the Anger camera are similar for both models: spatial resolution and contrast-to-noise ratio are better with the Discovery NM 530c; count sensitivity is higher with the D SPECT.5 Initial hesitancy to embrace the new technology has several explanations: (1) substantially higher initial purchase cost (2-3 times compared to the traditional camera), (2) lack of clinical data—no clinical comparative studies preceded the introduction of the new technology, (3)
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