Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A radical imaging system for use in radical medicine using a movable pallet for moving the patient during radical imaging. With the movable pallet, the patient can be moved, such as rotated to a position such that signal attenuation and scattering can be decreased. The imaging system may also incorporate a collimator with finite focal length, or a collimator whose focal length and/or spatial resolution can be adjusted dynamically.

Abstract: 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.

Abstract: A nuclear imaging device for positioning detectors in proximity to a subject generally includes one or more detectors disposed with respect to one another at an angle and at a distance from the subject. Each of the detectors has a field of view having a spatial window for receiving radiation. A positioning assembly is included for radially disposing the detectors away from the subject when one of the spatial windows receives attenuated radiation and toward the subject when non-attenuated radiation is received. A method according to the invention includes disposing a subject between a source of radiation and a field of view of the detectors, receiving radiation emanating from the source within the spatial window, determining the spatial location of the subject based on the radiation received, and positioning the detectors or the subject relative to the other based on the spatial location of the subject.

Abstract: Method and arrangement for implementing a system (10) for providing multi-angular SPECT radiation sampling utilizing slant-angle collimation. The system (10) includes a collimator (13) positioned between a radiating mass (19) within a patient (60) and a radiation detector (21). The collimator (13) is spaced apart from a translational path (25) of the radiating mass (19) at a predefined distance (24). A plurality of apertures (27) extend through the collimator (13) and each forms a passageway (28) for radiation rays (20) emanating from the radiating mass (19) in a direction substantially aligned with a longitudinal axis (29) of the respective passageway (29) and in this manner enables the aligned radiation rays (20) to strike the radiation detector (21).

Abstract: 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.

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

Abstract: 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.

Abstract: A collimator is in the shape of a closed curve and has one and only one focal point. The collimator is dimensioned such that, in use, the focal point may be positioned inside the body organ to be imaged. The focal point is caused to densely trace over the body organ of interest to form a tomographic image in less time, without imaging the rest of the body slice.

Abstract: Image data are acquired of an object along a given nominal view direction as well as at other view directions which are slightly off-axis with respect to the nominal view direction. The image data is used to produce an enhanced image of the view along the nominal view direction and to compensate for at least some of the effects of finite angular resolution of the camera collimator.

Abstract: A collimator collimates radiation so that each beam passes through two focal lines. One of the lines is in a transaxial plane and the other line is in an axial plane. The focal length in the transaxial plane is longer than is the focal length in the axial plane. In the preferred embodiment, the focal lines are perpendicular, whereby an anamorphic collimator is produced. Alternatively, the focal lines are nonparallel, producing an astigmatic collimator.

Abstract: A bilateral collimator for rotational camera transaxial SPECT imaging of small body organs produces two different simultaneous views of a body organ to be imaged. The views are produced by groups of passageways which do not intersect each other.