Siemens Medical Solutions Usa, Inc.

Siemens Medical Systems, Inc.

University of Utah Research Foundation

Eric Grant Hawman

Gengsheng Lawrence Zeng

A Hans Vija

Trudy Dayle Rempel

Manjit Ray

Robert Kasper

Ray S Xu

A system and method are disclosed for obtaining pointing directions for every channel of a collimator which can then be used during the image reconstruction process to more accurately estimate the direction from which radiation has been received. The disclosed system and method provide for photographic measurement and analysis of individual collimator channel to determine the pointing directions for every channel in the collimator. This information is obtained by photographing the front and back sides of the collimator, and analyzing the digital image data to obtain the pointing angle of each channel. The resulting information, referred to as a 'vector map' is included in the firmware of the collimator so that it can be called on during the projection and back-projection steps of the algorithm.

System and method for photographic determination of multichannel collimator channel pointing directions

A multi-view composite collimator includes a first parallel collimator segment having a plurality of collimator channels oriented at a first slant angle and a second parallel collimator segment adjacent to the first parallel collimator segment having a plurality of collimator channels oriented at a second slant angle different from the first slant angle and a bridging collimating element is provided between the first and second parallel collimator segments, wherein radiation can pass through the bridging collimating element.

Composite segment collimators for SPECT without dead zones

An apparatus and method for nuclear medical imaging (e.g., SPECT imaging) using cone-beam or multifocal collimators is disclosed. According to the embodiment of the invention, the detector/collimator is tilted in a fore-aft direction, with the tilt angle varying as a function of the orbital position of the detector assembly. The patient pallet may also be moved longitudinally as a function of the tilt angle (i.e., as a function of the orbital position) for optimal image quality.

Tomographic sampling for SPECT with cone-beam or multifocal collimation

A method and system for compensating truncated transmission projection data used for attenuation correction in a SPECT apparatus. The method and system include generating an initial estimate of a transmission reconstruction without modeling source geometry or detector collimator response and refining the transmission reconstruction by using the initial estimate with a modified model of the source geometry and the collimation geometry.

Truncation compensation in transmission reconstructions for a small FOV cardiac gamma camera

A method of iteratively reconstructing images from data acquired by converging collimation SPECT, comprising the steps of dividing a reconstruction space into multiple iso-resolution zones that are oriented non-parallel to the detector, and correcting for attenuation by applying a same attenuation value to all voxels in the same iso-resolution zone.

Method for faster iterative reconstruction for converging collimation spect with depth dependent collimator response modeling

A method for optimizing imaging dwell time during nuclear imaging. A fast pre-scan is conducted over the angular range of imaging, with equal dwell time at each position. A statistical sub-sampling is conducted over a region of interest to a desired fraction of the acquisition time. The statistical sub-sampling is used to simulate a varying dwell time tomographic dataset according to a profile pre-generated by an analysis of patient specific anatomic or functional information. Reconstructed data with equal dwell time and with simulated adaptive dwell time are constructed and compared to generate a difference image, a parameter of interest of which is evaluated. If the parameter of interest is within an acceptable level, the reduced dwell time for the given angular position is established; otherwise, the fraction is varied and the process is repeated. Once dwell times are computed for all view angles, a full scan is conducted.

Application-driven optimization of acquisition and reconstruction of SPECT/PET projection data

Transaxial radionuclide imaging is implemented without relative rotation between detectors and a patient by employing a collimator comprising segments sharing a common central axis, each segment having a plurality of apertures extending therethrough, wherein the segments are angularly displaced from one another about the common central axis. Embodiments include SPECT systems comprising a polygonal detector having a collimator on at least two sides thereof. Embodiments further include collimators comprising six segments, each offset by an angle of 7 to 9&#xb0;.

Non-rotating transaxial radionuclide imaging

A nuclear medicine imaging system includes a bed having a direction of translation, a detector disposed rotationally about an axis of rotation substantially parallel to the direction of translation, and a radioactive line source disposed rotationally about the bed substantially opposite the detector at a first predetermined non-zero angle to the axis of rotation and a second predetermined non-zero angle to a plane of rotation of the detector. The bed may be translated along the along the direction of translation while the detector is rotated about the axis of rotation.

Method and apparatus for simultaneous emission and transmission spect using oblique line sources

According to the present invention, an improved source collimator for use in nuclear medicine imaging is provided. The improved source collimator utilizes a larger collimation angle than has previously been used in the art. The use of the larger collimation angle for the source collimator reduces the sensitivity of the nuclear medical imaging systems to misalignment between the detector and the source collimators.

Collimators for an array of radioactive lines for use on a spect system for non-uniform attenuation correction measurements

According to the present invention, a novel slat collimator for use in nuclear medicine imaging is provided. The slat collimator comprises a first layer comprising a plurality of spaced apart elongated slats and a second layer comprising a plurality of spaced apart elongated slats. The slats of the second layer are positioned orthogonally with respect to the slats of the first layer. The slats are constructed of a radiation attenuation material and the spaces between the slats may be non-variable or variable.

Collimator with variable focusing and direction of view for nuclear medicine imaging

Attenuation correction in SPECT studies such as cardiac function imaging is carried out using an iterative statistically-based transmission projection reconstruction algorithm that is capable of modeling overlapping transmission beams from a line source array of radiation emitters. Downscatter between emission and transmission photons is additively corrected for in the algorithm. Optimal line source spacing techniques and source collimation angle selection are derived to improve performance and reduce cost.

Attenuation correction in nuclear medicine studies by simultaneous transmission and emission data measurement and estimation of emission-to-transmission crosstalk

Method and arrangement for implementing a system () for providing multi-angular SPECT radiation sampling utilizing slant-angle collimation. The system () includes a collimator () positioned between a radiating mass () within a patient () and a radiation detector (). The collimator () is spaced apart from a translational path () of the radiating mass () at a predefined distance (). A plurality of apertures () extend through the collimator () and each forms a passageway () for radiation rays () emanating from the radiating mass () in a direction substantially aligned with a longitudinal axis () of the respective passageway () and in this manner enables the aligned radiation rays () to strike the radiation detector (). The plurality of passageways () include a first group () of passageways adjacently aligned in a first row () and arranged so that the longitudinal axes () of the first group () of passageways () are substantially contained in a first plane () oriented substantially perpendicularly to a central plane () of the collimator (). Each of the parallel longitudinal axes () of the first row () of passageways are obliquely oriented with respect to the central plane () of the collimator () with an included angle () therebetween. Each of the included angles, when measured clockwise from the central plane () or face of the collimator () to a respective longitudinal axis, is an acute angle.

System and method for providing slant-angle collimation for nuclear medical imaging

Two conjugate views of a patient are acquired during a SPECT nuclear medicine study. A common anatomical feature is identified in the views. Based on the differences in location of the common feature in the views, the center of rotation ('COR') of the detector during the study can be calculated after the study has been concluded. This COR can then be used during image reconstruction to determine the location at which each filtered view is backprojected. The resulting SPECT data is of higher quality because COR artifacts in the reconstructed image are reduced or eliminated.

Retrospectively determining the center of rotation of a scintillation

The focus of a fan beam collimator is offset from the centerline.

Fan-beam collimator with offset focus and scintillation camera system

An energy window of a scintillation camera system is set to include only events which have been Compton-scattered within a slice of the body of a patient undergoing a SPECT examination. From events so acquired, a scatter image is reconstructed. The scatter image is processed to define therewithin a plurality of regions of constant attenuation coefficient. This information can be used during the normal image reconstruction process to eliminate artifacts caused by variation in attenuation coefficient.

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Schaumburg, IL, United States of America

Eric Grant Hawman