The effect of acquisition interval and spatial resolution on dynamic cardiac imaging with a stationary SPECT camera

A fast cardiac gamma camera with dynamic SPECT capabilities: design, system validation and future potential

PURPOSE

The 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.

METHODS

DNM 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.

RESULTS

DNM sensitivity was more than threefold higher while SR was notably better. Significantly, SR was the same for (99m)Tc and (201)Tl. ER was improved on DNM and allowed good separation of (99m)Tc and (123)I 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.

CONCLUSION

DNM 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.

Myocardial perfusion SPECT using a rotating multi-segment slant-hole collimator

PURPOSE

A rotating multi-segment slant-hole (RMSSH) collimator is able to provide much higher (approximately 3 times for four-segment collimator with 30 degrees slant angle) sensitivity than a parallel-hole (PH) collimator with the similar spatial resolution for imaging small organs such as the heart and the breast. In this article, the authors evaluated the performance of myocardial perfusion SPECT (MPS) using a RMSSH collimator compared to MPS using the low-energy high-resolution parallel-hole collimators.

METHODS

The authors conducted computer simulation studies using the NURBS-based cardiac-torso phantom, receiver operative characteristic (ROC) analysis using the channelized Hotelling observer, physical phantom experiments, and pilot patient studies to evaluate the performance of MPS using a rotating four-segment slant-hole (R4SSH) collimator with respect to MPS using a PH collimator.

RESULTS

In the simulation study, the R4SSH MPS provides images with superior contrast-noise trade-off than those of PH MPS with the same acquisition time. The defect detectability in terms of the largest area under the ROC curve for R4SSH MPS is significantly higher than those of PH MPS with p-values < 0.01. In the phantom experiments, the R4SSH MPS images with 7.5 min acquisition had similar noise level and overall image quality as those of PH MPS with 21 min acquisition. Pilot patient studies showed that with the same acquisition time, the R4SSH SPECT using a single-head camera gave images with similar quality as those of PH SPECT using a dual-head camera.

CONCLUSIONS

The RMSSH SPECT has a potential to improve the coronary artery disease detection and workflow of SPECT imaging acquisition due to the high sensitivity property of the RMSSH collimator.