Cramer-Rao lower bound optimization of an EM-CCD-based scintillation gamma camera.

Scintillation gamma cameras based on low-noise electron multiplication (EM-)CCDs can reach high spatial resolutions. For further improvement of these gamma cameras, more insight is needed into how various parameters that characterize these devices influence their performance. Here, we use the Cramer-Rao lower bound (CRLB) to investigate the sensitivity of the energy and spatial resolution of an EM-CCD-based gamma camera to several parameters.

Improved EMCCD gamma camera performance by SiPM pre-localization.

High spatial resolution γ-imaging can be achieved with scintillator readout by low-noise, fast, electron-multiplying charge-coupled devices (EMCCDs). Previously we have shown that false-positive events due to EMCCD noise can be rejected by using the sum signal from silicon photomultipliers (SiPMs) mounted on the sides of the scintillator. Here we launch a next generation hybrid CCD-SiPM camera that utilizes the individual SiPM signals and maximum likelihood estimation (MLE) pre-localization of events to discriminate between true and false events in CCD frames.

Experimental comparison of high-density scintillators for EMCCD-based gamma ray imaging.

Detection of x-rays and gamma rays with high spatial resolution can be achieved with scintillators that are optically coupled to electron-multiplying charge-coupled devices (EMCCDs). These can be operated at typical frame rates of 50 Hz with low noise. In such a set-up, scintillation light within each frame is integrated after which the frame is analyzed for the presence of scintillation events.

Maximum-likelihood scintillation detection for EM-CCD based gamma cameras.

Gamma cameras based on charge-coupled devices (CCDs) coupled to continuous scintillation crystals can combine a good detection efficiency with high spatial resolutions with the aid of advanced scintillation detection algorithms. A previously developed analytical multi-scale algorithm (MSA) models the depth-dependent light distribution but does not take statistics into account. Here we present and validate a novel statistical maximum-likelihood algorithm (MLA) that combines a realistic light distribution model with an experimentally validated statistical model.

An enhanced high-resolution EMCCD-based gamma camera using SiPM side detection.

Electron-multiplying charge-coupled devices (EMCCDs) coupled to scintillation crystals can be used for high-resolution imaging of gamma rays in scintillation counting mode. However, the detection of false events as a result of EMCCD noise deteriorates the spatial and energy resolution of these gamma cameras and creates a detrimental background in the reconstructed image. In order to improve the performance of an EMCCD-based gamma camera with a monolithic scintillation crystal, arrays of silicon photon-multipliers (SiPMs) can be mounted on the sides of the crystal to detect escaping scintillation photons, which are otherwise neglected.