PurposeThe goal of this study is to present the Discovery NM 530c (DNM), a cardiac SPECT camera, interfacing multi-pinhole collimators with solid-state modules, aiming at slashing acquisition time without jeopardizing quality. DNM resembles PET since it enables 3-D SPECT without detector motion. We further envision how these novel capabilities may help with current and future challenges of cardiac imaging.MethodsDNM sensitivity, spatial resolution (SR) and energy resolution (ER), count rate response, cardiac uniformity and cardiac defect contrast were measured and compared to a dedicated cardiac, dual-head standard SPECT (S-SPECT) camera.ResultsDNM sensitivity was more than threefold higher while SR was notably better. Significantly, SR was the same for 99mTc and 201Tl. ER was improved on DNM and allowed good separation of 99mTc and 123I spectral peaks. Count rate remained linear on DNM up to 612 kcps, while S-SPECT showed severe dead time limitations. Phantom studies revealed comparable uniformity and defect contrast, notwithstanding significantly shorter acquisition time for the DNM. First patient images, including dynamic SPECT, are also presented.ConclusionDNM is raising the bar for expedition and upgrade of practice. It features high sensitivity as well as improved SR, temporal resolution and ER. It enables reduction of acquisition time and fast protocols. Importantly, it is potentially capable of dynamic 3-D acquisition. The new technology is potentially upgradeable and may become a milestone in the evolution of nuclear cardiology as it assumes its key role in molecular imaging of the heart.

This study provides Class III evidence that for patients with an acute migraine headache, remote nonpainful electrical stimulation on the upper arm skin reduces migraine pain.

Gated (82)Rb PET during pharmacologic stress allows for assessment of the functional response to vasodilation. The magnitude of LVEF increase is determined by stress perfusion/reversible perfusion defects. Functional response to hyperemia may thus be incorporated in future evaluations of diagnostic and prognostic algorithms based on (82)Rb PET.

A Data Spectrum torso phantom was prepared to model the low-dose rest part of a standard one-day myocardial perfusion protocol. The 99mTc activity concentration ratios within the phantom for heart : liver : background tissue : lung were 9 : 4.5 : 1 : O. Projection data were acquired for 4 minutes on the novel, CZT detector based multi-pinhole Ultra-Fast Cardiac (UFC) SPECT system developed by GE Healthcare. In this system, the detectors and collimators do not move during acquisition -all lines of response are acquired simultaneously. A 126-154 keY energy window (140 keY ± 10%) was used for all acquisitions. B. Energy response modelsTwo energy response kernels were analyzed: (1) The ideal response in the form of a delta function, and (2) the CZT response that was experimentally measured. A spectrum from a 99mTc point source in air was acquired with the UFC system in bins of 0.5 keY (Fig. 1). It can be seen from the figure that the CZT spectrum is asymmetrical -that is, when the peak of the spectrum occurs at 140 keV, more counts are observed in the <126,140> keY window than in the <140,156> keY window. This low-energy tail response is characteristic of pixilated CZT detectors, and it differentiates their response from that of typical scintillator-based detectors, which tend to have a more symmetrical Gaussian photopeak 160 140 120 60 80 100 E(keV) 40 CZT Detector Response to 140 keY Gammas 20Abstract-The goal of this study was to evaluate the effect of the detector energy response on the quality of 99mTc myocardial perfusion SPECT images. A Data Spectrum torso phantom was prepared to model the low-dose rest portion of a standard oneday myocardial perfusion protocol. Projection data were acquired with a recently developed Ultra-Fast Cardiac SPECT System (UFC, GE Healthcare). UFC utilizes an array of CZT detector modules and pinhole collimators. A point source in air was used to measure the 99mTc spectrum in CZT. In addition to acquiring emission data, the phantom was scanned with high resolution CT and converted into a 3D model for the SimSET Monte Carlo simulation package, which was then used to generate photon history files. We developed a collimator-detector response module that operates on the SimSET photon history files. This module performs multi-pinhole collimation followed by a stochastic energy blurring operation and generates projection data. The simulated CZT detector response was derived from a measured spectrum, and ideal energy response served as reference. Simulation results were compared to actual torso phantom acquisitions. Components of the resulting projection data (amount of primary and scattered photons) and reconstructed slices were compared. For fixed energy acceptance windows, the asymmetric CZT energy response shape leads to a 30% reduction of the scatter component in measured data and contributes to superior reconstructed image quality.

As the results show, a combination of the SLO and LROC/EROC curves can determine the configuration that yields the most relevant estimation/detection information. Thus, this is a useful method for assessing cardiac SPECT systems.