Abstract: A method of processing a positron emission tomography (PET) imaging data set (30) acquired of a subject includes independently localizing each positron-electron annihilation event of the PET imaging data set based on time of flight (TOF) localization of the positron-electron annihilation event to form a generated image (34). The generated image may be displayed. The generated image is suitably used as the basis for an initial image of an iterative reconstruction (40) of the PET imaging data set (30) to produce a reconstructed image (42). A spatial contour (56) of an image of the subject in the PET imaging data set (30) is suitably delineated based on the generated image (34). A subject attenuation map (62) for use in PET image reconstruction (40) is suitably constructed based in part on the spatial contour (56).

Abstract: When compensating for truncated patient scan data acquired by a multi-modal PET/CT or PET/MR imaging system (14, 16), such as occurs when a patient is larger than a field of view for an anatomical imaging device, a segmented contour of a non-attenuation-corrected (NAC) PET image is used to identify a contour of the truncated region. An appropriate tissue type is used to fill in truncated regions of a truncated CT or MR image for the attenuation map. The corrected attenuation map is then used to generate an attenuation-corrected PET image of the patient or a region of interest. Alternatively, the system can be employed in PET/CT or PET/MR imaging scenarios where two modalities are performed sequentially (e.g., not simultaneously), and thus the contour derived from the PET scan can be compared to the CT or MR image to infer potential subject motion between the PET and CT or MR scans.

Abstract: A gamma camera includes a plurality of detectors (32, 34) for detecting emission radiation emitted from within a subject and transmission radiation which has traversed a subject to be imaged, the subject attenuating the radiation. Each detector generates position and energy data. At least one transmission radiation source (54, 54′) transmits transmission radiation through an examination region (36) to a first segment (74, 74′) of the opposite detector. In one embodiment, segment selector circuitry (88) connected with the detectors selectively disables a portion of each detector head during collection of emission data, transmission data, or both. In another embodiment, transmission radiation is received by the first segment (74, 74′) simultaneously with emission radiation being received by a second segment (72, 72′) of each detector. The first segment is uncollimated or collimated for the transmission radiation source.

Abstract: A continuous rotation sampling scheme for use with a nuclear medicine gamma camera facilitates collection of transmission and emission data leading to a reduced overall scan time. The gantry (16) contains a plurality of radiation detector heads (20a-20c) with planar faces and at least one adjustably mounted radiation source (30a). During transmission data collection, the gantry (16) continuously rotates about a subject receiving aperture (18) while the radiation source (30a) continuously rasters back and forth across the field of view. The detected transmission radiation (32a) is reconstructed into an attenuation volumetric image representation by a transmission reconstruction processor (64t). The transmission reconstruction processor (64t) performs a fan beam reconstruction algorithm in each of a multiplicity of planes perpendicular to an axis of rotation.

Abstract: An asymmetric sampling scheme for use with a nuclear medicine gamma camera facilitates collection of a full set of higher resolution emission data and lower resolution transmission data with one complete 360° rotation of the gantry. The gantry (16) contains a plurality of radiation detectors (20a-20c) and at least one adjustably mounted radiation source (30a). During a scan, the gantry (16) is incrementally rotated about a subject receiving aperture (18) by a predetermined step size throughout a first 180° of a rotation (P1, . . . , P6). The gantry (16) is then rotated about the subject receiving aperture (18) by one-half the predetermined step size (P7 or P8). The gantry (16) is then incrementally rotated about the subject receiving aperture (18) by the predetermined step size throughout the remaining 180° of the scan (P8, . . . , P2). Emission data collected during the second half of the scan (P8, . . . , P12) is interleaved into the data from the first half of the scan.

Abstract: A SPECT system includes three gamma camera heads (22a), (22b), (22c) which are mounted to a gantry (20) for rotation about a subject (12). The subject is injected with a source of emission radiation, which emission radiation is received by the camera heads. Transmission radiation from a transmission radiation source (30) is truncated to pass through a central portion of the subject but not peripheral portions and is received by one of the camera heads (22a) concurrently with the emission data. As the heads and radiation source rotate, the transmitted radiation passes through different parts or none of the peripheral portions at different angular orientations. An ultrasonic range arranger (152) measures an actual periphery of the subject. Attenuation properties of the subject are determined by reconstructing (90") the transmission data using an iterative approximation technique and the measured actual subject periphery.

Abstract: A SPECT system includes three gamma camera heads (22a), (22b), (22c) which are mounted to a gantry (20) for rotation about a subject (12). The subject is injected with a source of emission radiation, which emission radiation is received by the camera heads. A reconstruction processor (112) reconstructs the emission projection data into a distribution of emission radiation sources in the subject. Transmission radiation from a radiation source (30) passes through the subject and is received by one of the camera heads (22a) concurrently with the emission radiation. The transmission radiation data is reconstructed into a three-dimensional CT type image representation of radiation attenuation characteristics of each pixel of the subject. An attenuation correction processor (118) corrects the emission projection data to compensate for attenuation along the path or ray that it traversed. In this manner, an attenuation corrected distribution of emission sources is generated.