Using liquid crystals to control the propagation of microwaves is a potentially interesting technology. By incorporating small amounts of liquid crystal in thin slat metal structures through which the microwaves may resonantly pass a whole new range of voltage tuned microwave devices are becoming available. Metallic sub-wavelength slit structures at microwave frequencies have been constructed w...

The purpose of this study was to evaluate the effects of voxel size and iterative reconstruction parameters on the radial and tangential resolution for 99mTc SPECT as a function of radial distance from isocenter. SPECT/CT scans of eight coplanar point sources of size smaller than 1 mm3 containing high concentration 99mTc solution were acquired on a SPECT/CT system with 5/8 inch NaI(Tl) detector...

This article considers a hypothetical imaging device with a spinning slat collimator that measures parallel-planar-integral data from an object. This device rotates around the object 180 degrees and stops at N positions uniformly distributed over this 180 degrees. At each stop, the device spins on its own axis 180 degrees and acquires measurements at M positions uniformly distributed over this ...

The qualitative and quantitative accuracy of SPECT images is degraded by physical factors of attenuation, Compton scatter and spatially varying collimator geometric response. This paper presents a 3D ray-tracing technique for modelling attenuation, scatter and geometric response for SPECT imaging in an inhomogeneous attenuating medium. The model is incorporated into a three-dimensional projecto...

OBJECTIVE To develop a small-animal SPECT system using a low cost commercial portable gamma camera equipped with a pinhole collimator, a continuous scintillation crystal and a position-sensitive photomultiplier tube. MATERIAL AND METHODS The gamma camera was attached to a variable radius system, which enabled us to optimize sensitivity and resolution by adjusting the radius of rotation to the...

et al. Analysis and reduction of eddy current effects induced by tesseral end zonal gradient coils in different collimator geometries for SPECT/MRI integration. permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

PURPOSE Myocardial sympathetic imaging with 123I-meta-iodobenzylguanidine (123I-mIBG) has gained clinical momentum. Although the need for standardization of 123I-mIBG myocardial uptake has been recognized, the availability of practical clinical standardization approaches is limited. The need for standardization includes the heart-to-mediastinum ratio (HMR) and washout rate with planar imaging, ...

UNLABELLED Pinhole SPECT (P-SPECT) has proven to be a high-resolution and sensitive method in both experimental and clinical studies. In this study, we investigated whether P-SPECT combined with conventional planar scintigraphy can give additional information in hyperfunctioning parathyroid gland detection in both primary hyperparathyroidism (pHPT) and secondary hyperparathyroidism (sHPT) since...