Dov Rosenfeld

Bio: Dov Rosenfeld is an academic researcher from Stanford University. The author has contributed to research in topics: Aperture & Pinhole (optics). The author has an hindex of 2, co-authored 2 publications receiving 57 citations.

Variable code gamma ray imaging system

Abstract: A gamma-ray source distribution in the body is imaged onto a detector using an array of apertures. The transmission of each aperture is modulated using a code such that the individual views of the source through each aperture can be decoded and separated. The codes are chosen to maximize the signal to noise ratio for each source distribution. These codes determine the photon collection efficiency of the aperture array. Planar arrays are used for volumetric reconstructions and circular arrays for cross-sectional reconstructions.

Time Modulated Apertures for Tomography in Nuclear Medicine

Abstract: This paper presents techniques for overcoming the shortcomings inherent in known methods for imaging three-dimensional ?-ray sources as encountered in nuclear medicine. Conventional pinhole and collimator cameras have low efficiency and do not display depth information. Coded aperture systems have high photon collection efficiencies, but their noise performance is worse than that of conventional apertures for sources of interest. Multiple view systems, with either cone beam or transverse axial geometries, have low efficiencies. This paper presents a general theory for increasing the efficiency of such multiple view systems. Source dependent time-modulated apertures are used. In other words, a particular modulating function is chosen according to the characteristics of the source being imaged. A statistically optimal demodulating method is used. The final image is that of a chosen source plane, without the out-of-focus background produced by other imaging methods.

Coded aperture imaging with uniformly redundant arrays

Abstract: A system utilizing uniformly redundant arrays to image non-focusable radiation. The uniformly redundant array is used in conjunction with a balanced correlation technique to provide a system with no artifacts such that virtually limitless signal-to-noise ratio is obtained with high transmission characteristics. Additionally, the array is mosaicked to reduce required detector size over conventional array detectors.

Radioactive emission detector equipped with a position tracking system and utilization thereof with medical systems and in medical procedures

Abstract: A system for calculating a position of a radioactivity emitting source in a system-of-coordinates, the system comprising (a) a radioactive emission detector; (b) a position tracking system being connected to and/or communicating with the radioactive emission detector; and (c) a data processor being designed and configured for receiving data inputs from the position tracking system and from the radioactive emission detector and for calculating the position of the radioactivity emitting source in the system-of-coordinates.

Radioactive emission detector equipped with a position tracking system

Abstract: A radioactive emission probe in communication with a position tracking system and the use thereof in a variety of systems and methods of medical imaging and procedures, are provided. Specifically, wide aperture collimation—deconvolution algorithms are provided, for obtaining a high-efficiency, high resolution image of a radioactivity emitting source, by scanning the radioactivity emitting source with a probe of a wide-aperture collimator, and at the same time, monitoring the position of the radioactive emission probe, at very fine time intervals, to obtain the equivalence of fine-aperture collimation. The blurring effect of the wide aperture is then corrected mathematically. Furthermore, an imaging method by depth calculations is provided, based on the attenuation of photons of different energies, which are emitted from the same source, coupled with position monitoring.

Multi-dimensional image reconstruction

Abstract: Apparatus for radiation based imaging of a non-homogenous target area having distinguishable regions therein, comprises: an imaging unit configured to obtain radiation intensity data from a target region in the spatial dimensions and at least one other dimension, and an image four-dimension analysis unit analyzes the intensity data in the spatial dimension and said at least one other dimension in order to map the distinguishable regions. The system typically detects rates of change over time in signals from radiopharmaceuticals and uses the rates of change to identify the tissues. In a preferred embodiment, two or more radiopharmaceuticals are used, the results of one being used as a constraint on the other.

Semiconductor sensor for gamma-ray tomographic imaging system

Abstract: A hybrid gamma-ray semiconductor detector is used in combination with attenuating apertures of the kind used in emission computed tomography. The detector comprises a slab of semiconductor material partitioned into multiple cells individually connected to a multiplexer through indium-bump pressure welds for the sequential read-out of integrated pulses generated in each cell as a result of gamma-ray absorption events. The single output channel provided by the multiplexer permits the construction of semiconductor sensor cells approximately one millimeter in size for improved spatial resolution of the detector. The greater resolution of the detector makes it possible to narrow the distance between the image forming apertures and the detector's surface, thus minimizing overlapping of the gamma-ray radiation and the size of the overall apparatus. As a result of the smaller acceptable distance between the aperture surface and the detector, it is also possible to have a greater number of apertures without overlap with a resulting substantial improvement in system sensitivity.