Development and Applications of Compton Camera-A Review

The history of Compton cameras began with the detection of radiation sources originally for applications in astronomy. A Compton camera is a promising γ-ray detector that operates in the wide energy range of a few tens of keV to MeV. The γ-ray detection method of a Compton camera is based on Compton scattering kinematics, which is used to determine the direction and energy of the γ-rays without using a mechanical collimator. Although the Compton camera was originally designed for astrophysical applications, it was later applied in medical imaging as well. Moreover, its application in environmental radiation measurements is also under study. Although a few review papers regarding Compton cameras have been published, they either focus very specifically on the detectors used in such cameras or the particular applications of Compton cameras. Thus, the aim of this paper is to review the features and types of Compton cameras and introduce their applications, associated imaging algorithms, improvement scopes, and their future aspects.

Design Study of an Ultrahigh Resolution Brain SPECT System Using a Synthetic Compound-Eye Camera Design With Micro-Slit and Micro-Ring Apertures

In this paper, we discuss the design study for a brain SPECT imaging system, referred to as the HelmetSPECT system, based on a spherical synthetic compound-eye (SCE) gamma camera design. The design utilizes a large number (  ∼ 500 ) of semiconductor detector modules, each coupled to an aperture with a very narrow opening for high-resolution SPECT imaging applications. In this study, we demonstrate that this novel system design could provide an excellent spatial resolution, a very high sensitivity, and a rich angular sampling without scanning motion over a clinically relevant field-of-view (FOV). These properties make the proposed HelmetSPECT system attractive for dynamic imaging of epileptic patients during seizures. In ictal SPECT, there is typically no prior information on where the seizures would happen, and both the imaging resolution and quantitative accuracy of the dynamic SPECT images would provide critical information for staging the seizures outbreak and refining the plans for subsequent surgical intervention.We report the performance evaluation and comparison among similar system geometries using non-conventional apertures, such as micro-ring and micro-slit, and traditional lofthole apertures. We demonstrate that the combination of ultrahigh-resolution imaging detectors, the SCE gamma camera design, and the micro-ring and micro-slit apertures would offer an interesting approach for the future ultrahigh-resolution clinical SPECT imaging systems without sacrificing system sensitivity and FOV.

Challenges for Microelectronics in Non-Invasive Medical Diagnostics

Microelectronics is emerging, sometimes with changing fortunes, as a key enabling technology in diagnostics. This paper reviews some recent results and technical challenges which still need to be addressed in terms of the design of CMOS analog application specific integrated circuits (ASICs) and their integration in the surrounding systems, in order to consolidate this technological paradigm. Open issues are discussed from two, apparently distant but complementary, points of view: micro-analytical devices, combining microfluidics with affinity bio-sensing, and gamma cameras for simultaneous multi-modal imaging, namely scintigraphy and magnetic resonance imaging (MRI). The role of integrated circuits is central in both application domains. In portable analytical platforms, ASICs offer miniaturization and tackle the noise/power dissipation trade-off. The integration of CMOS chips with microfluidics poses multiple open technological issues. In multi-modal imaging, now that the compatibility of the acquisition chains (thousands of Silicon Photo-Multipliers channels) of gamma detectors with Tesla-level magnetic fields has been demonstrated, other development directions, enabled by microelectronics, can be envisioned in particular for single-photon emission tomography (SPECT): a faster and simplified operation, for instance, to allow transportable applications (bed-side) and hardware pre-processing that reduces the number of output signals and the image reconstruction time.