A Novel High-Sensitivity Rapid-Acquisition Single-Photon Cardiac Imaging Camera

Abstract

This study described and validated a new solid-state singlephoton g-camera and compared it with a conventional-SPECT Anger camera. The compact new camera uses a unique method for localizing g-photon information with a bank of 9 solid-state detector columns with tungsten collimators that rotate independently. Methods: Several phantom studies were performed comparing the new technology with conventional-SPECT technology. These included measurements of line sources and single-and dual-radionuclide studies of a torso phantom. Simulations were also performed using a cardiothoracic phantom. Furthermore, 18 patients were scanned with both the new camera and a conventional-SPECT camera. Results: The new camera had a count sensitivity that was 10 times higher than that of the conventional camera and a compensated spatial resolution that was moderately better. Dual-radionuclide studies using a phantom show the further potential of the new camera for a 2-tracer simultaneous acquisition. Two-minute clinical studies with the new camera and 11-min studies with the conventional camera qualitatively showed good-to-excellent image quality and improved myocardial edge definition for the new camera. Conclusion: These initial performance characteristics of a new solid-state single-photon g-camera offer great promise for clinical dynamic SPECT protocols, with important implications for applications in nuclear cardiology and molecular imaging. Nucl ear medicine has evolved as a clinical and research discipline for the noninvasive assessment of physiologic and molecular function in normal and diseased tissues. Principally performed with nanomolar quantities of administered radiopharmaceuticals and an external scintillation camera, nuclear medicine imaging uses 2 types of modalities: singlephoton imaging (including planar imaging and SPECT) and PET, with the former comprising nearly three fourths of all clinical procedures. With SPECT, myocardial perfusion studies predominate; these studies were performed in approximately 7,000,000 patients in the United States in 2004 and provided images of relative myocardial perfusion at rest and under stress. By assessing the extent of ischemic and infarcted myocardium, SPECT provides noninvasive information that has become central in clinical decision making, determining the need for invasive cardiac catheterization and myocardial revascularization in many patients (1,2).SPECT is typically performed using an Anger scintillation camera, named after its inventor, Hal Anger (3). Most myocardial SPECT is performed with 2 scintillation cameras oriented at 90°and mounted on a gantry that rotates around the patient. Typically, each scintillation camera is equipped with parallel-hole high-resolution collimators. Since collimation is necessary to acquire the projection views, only 0.02% of the photons emitted from the heart are collected. As a result, acquisition times of 10-20 min are required for myocardial SPECT studies. Although new detector technologies using solid-state materials have been explored (...

Reduced administered activity, reduced acquisition time, and preserved image quality for the new CZT camera

“…Recently, a new generation of gamma camera systems was introduced based on a novel detector technology utilizing semiconductor detectors of Cadmium Zinc Telluride (CZT) [1,2]. This technology is associated with higher sensitivity and better spatial and energy resolution compared to conventional MPS and its agreement with conventional MPS using a NaI-crystal technology has been clinically validated in several studies [3][4][5][6][7].…”

Dynamic SPECT: evolution of a widely available tool for the assessment of coronary flow reserve

“…The detectors' orbit is limited by mechanical as well as safety factors and the angular projections obtained are inconsistent, resulting in blurred images and possible bias in the estimated kinetic parameters. In addition, conventional detector crystals suffer -014-2929-x from limited temporal resolution, and may not be able to collect adequate numbers of counts when tracer concentrations are rapidly changing, such as in dynamic acquisitions.Eur J Nucl Med Mol Imaging (2015) 42:302-304 DOI 10.1007/s00259Recently introduced dedicated cardiac cameras with cadmium zinc telluride (CZT) crystals provide significantly improved sensitivity (eight to ten times better than conventional SPECT) and significantly improved resolution and energy resolution [15,16]. These improvements, in addition to allowing focused imaging of the heart and the use of new reconstruction algorithms, enable dynamic SPECT with kinetic analysis of 99m Tc-MIBI myocardial concentrations to be performed in animals and humans [17][18][19][20], providing incremental diagnostic information over perfusion data alone [17].…”

“…Recently introduced dedicated cardiac cameras with cadmium zinc telluride (CZT) crystals provide significantly improved sensitivity (eight to ten times better than conventional SPECT) and significantly improved resolution and energy resolution [15,16]. These improvements, in addition to allowing focused imaging of the heart and the use of new reconstruction algorithms, enable dynamic SPECT with kinetic analysis of 99m Tc-MIBI myocardial concentrations to be performed in animals and humans [17][18][19][20], providing incremental diagnostic information over perfusion data alone [17].…”

Dedicated cardiac cameras: a new option for nuclear myocardial perfusion imaging

“…The D-SPECT camera system had been previously described and validated in a paper using simulation, various physical phantoms and pilot patient data [14]. In fact, various phantom studies were performed comparing the new technology with conventional SPECT camera, including measurements of line sources and single-and dualradionuclide studies of a torso phantom; moreover, simulations were also performed using a cardiothoracic phantom.…”