Self-Collimating SPECT With Multi-Layer Interspaced Mosaic Detectors

Abstract

Conventional singlephoton emission computed tomography (SPECT) relies on mechanical collimation whose resolution and sensitivity are interdependent, the best performance a SPECT system can attain is only a compromise of these two equally desired properties. To simultaneously achieve high resolution and sensitivity, we propose to use sensitive detectors constructed in a multi-layer interspaced mosaic detectors (MATRICES) architecture to accomplish part of the collimation needed. We name this new approach selfcollimation.We evaluate three self-collimating SPECT systems and report their imaging performance: 1) A simulated human brain SPECT achieves 3.88% sensitivity, it clearly resolves 0.5-mm and 1.0-mm hot-rod patterns at noise-free and realistic count-levels, respectively; 2) a simulated mouse SPECT achieves 1.25% sensitivity, it clearly resolves 50-μm and 100-μm hot-rod patterns at noise-free and realistic count-levels, respectively; 3) a SPECT prototype achieves 0.14% sensitivity and clearly separates 0.3-mm-diameter point sources of which the center-to-center neighbor distance is also 0.3 mm. Simulated contrast phantom studies show excellent resolution and signal-to-noise performance.The unprecedented system performance demonstrated by these 3 SPECT scanners is a clear manifestation of the superiority of the self-collimating approach over conventional mechanical collimation. It represents a potential paradigm shift in SPECT technology development.

Simulation of a gamma-ray imaging technique using detector response patterns

“…[30][31][32] In the medical field, there is a trend toward replacing metal collimators with self-shielding collimators. 33) Compton cameras and active coded-mask cameras have been enhanced to cover a full 4π FOV. [34][35][36][37][38][39][40][41][42][43][44] We introduce a novel gamma-ray imaging approach.…”

Characterization and Assessment of Projection Probability Density Function and Enhanced Sampling in Self-Collimation SPECT

“…But due to its essential role in enabling detectors to collect single photons' directional information [8], mechanical collimator has remained the irreplaceable backbone of generations of SPECT systems [9] and cast a firm ceiling on its imaging performance. Recently, we have proposed a new single-photon imaging concept termed self-collimation (SC) to break through this ceiling [10]. The core of the new concept is to replace part of the physical collimator with spatially distributed sensitive detectors.…”

“…Recently, we have proposed a new single-photon imaging concept termed self-collimation (SC) to break through this ceiling [ 10 ]. The core of the new concept is to replace part of the physical collimator with spatially distributed sensitive detectors .…”

“…This self-collimation setup enables detectors to perform the dual functions of 1) detecting gamma photons for image generation and 2) collimating for other detectors. The concept is validated through studies of three SC systems: one simulated human brain SPECT, one simulated mouse SPECT, and one proof of concept experimental prototype mouse SPECT [ 10 ]. All three systems use a MATRICES architecture which consists of a tungsten ring with many apertures and three detector rings.…”

“…Combined with rotational and translational sampling enhancement, we have demonstrated that SC-SPECT can achieve a breakthrough of SPECT imaging performance. For example, the simulated human brain SPECT achieves 3.88% sensitivity and clearly resolves 0.5-mm and 1.0-mm hot-rod patterns at noise-free and realistic count-levels, respectively [ 10 ].…”