Over 5 million cardiac single-photon emission computed tomography (SPECT) scans were performed in the USA in 2002, with even more studies anticipated for future years. Modern SPECT scanners consist of (typically two) large area gamma cameras which rotate slowly around the patient in a step-and-shoot mode collecting projection information over a scan duration of roughly 30 minutes. Tomographic reconstruction is only possible after the last projections have been completed and it is assumed that the tracer distribution has remained static (or in equilibrium) during the scan, although data can also be """"""""gated"""""""" according to the cardiac cycle to resolve wall-motion effects. The proposed dynamic rotating slant-hole (DyRoSH) SPECT scanner will collect full tomographic information every two seconds, by using stationary detectors mounted with slant-hole collimators which rotate at 30 rpm. With 5 projections being collected simultaneously, the spatial resolution and photon sensitivity of the DyRoSH scanner is anticipated to be at least as good as current conventional SPECT machines. The dynamic capability of DyRoSH scanner will have implications for more extensive motion correction (e.g. respiration, patient movements, upward creep) and more significantly, will open the door to true dynamic imaging and, potentially, the development of a broad spectrum of radiopharmaceuticals whose uptake and clearance from the myocardium will be accurately traced over time.
The specific aims of this project are: 1. to compare the imaging performance of the DyRoSH SPECT scanner with a state-of-the-art conventional SPECT scanner; 2. to examine and quantify weaknesses and limitations in the DyRoSH SPECT configuration; and 3. to explore potential benefits of the 2-second temporal resolution of the DyRoSH SPECT scanner. All the methods are based on clinically relevant computer simulations. Monte Carlo methods will be used to generate list-mode data for the scanner. ROC studies will be used for the comparison with conventional systems. Field-of-view limitations will be analyzed based on a patient database of anatomies. Kinetic parameter estimation in dynamic SPECT will be compared to existing technology. New patient motion methods will be explored within the DyRoSH context. Vastly improved clinical cardiac SPECT is anticipated from the successful development of DyRoSH scanning.
| Roberts, J; Maddula, R; Clackdoyle, R et al. (2007) The effect of acquisition interval and spatial resolution on dynamic cardiac imaging with a stationary SPECT camera. Phys Med Biol 52:4525-40 |
