摘要:
A coincidence transmission source serves to detect coincident activity from a radiation source. The coincidence transmission source includes a detector dedicated to collecting attenuation data. A collimated radiation source and a detector are positioned with respect to a tomography device such that only a selected strip of the imaging detector of the tomograph is illuminated such that events unrelated to the attenuation are eliminated. The coincidence transmission source includes a collimator in which is disposed a radiation source. An opening is defined by the collimator for exposing a selected portion of the imaging detectors of the tomograph device. Positioned behind the radiation source, relative to the imaging detectors, is the dedicated attenuation detector. The attenuation detector and collimator are designed to illuminate only a strip of the imaging detector, thereby eliminating events not of interest in the attenuation measurement. In a dual head tomograph device, one coincidence transmission source of the present invention is disposed opposite each bank of imaging detectors. The sources and the associated collimators are positioned to the side of each head at a slight angle relative to the respective head. The sources and detectors are fixed relative to the imaging heads. In order to obtain full coverage of the field of view (FOV) in the same manner as for an emission scan, the heads and sources are rotated about the center of the camera.
摘要:
A method and apparatus for producing radioactive transmission measurements to form multi-dimensional attenuation correction data with a point source of radiation, such as required in positron emission tomography applications. This involves the passing of the point source proximate the face of a selected each of the tomograph units for the formation of a 3-D image, or a selected portion of the tomograph units for a 2-D image. As such, attenuation data, transmission data, detector performance data, etc., can be obtained. This point source of radiation, in one embodiment, is rapidly circulated through a conduit that passes across each detector face under the influence of a transport fluid in, for example, an oscillatory motion to achieve a selected radiation field whereby calculation of transmission measurements within a body positioned within the tomograph scanner is achieved. When not being circulated, the radiation source is held within a shield. Circulation of the transport fluid, typically a hydraulic fluid, is typically accomplished using a positive displacement pump. Position sensors are used to monitor the movement of the source in the conduit as well as its position within the shield. Disconnect units permit removal of the radiation source, as contained in the shield, from the system without accessing any other portions of the system. In another embodiment, the point source is a CT device.
摘要:
A method and apparatus for producing radioactive transmission measurements to form a 2-D or a 3-D image with a point source of radiation, such as required in positron emission tomography applications. This involves the passing of the point source proximate the face of a selected each of the tomograph units for the formation of a 3-D image, or a selected portion of the tomograph units for a 2-D image. As such, attenuation data, transmission data, detector performance data, etc., can be obtained. This point source of radiation is rapidly circulated through a conduit that passes across each detector face under the influence of a transport fluid in, for example, an oscillatory motion to achieve a selected radiation field whereby calculation of transmission measurements within a body positioned within the tomograph scanner is achieved. When not being circulated, the radiation source is held within a shield. Circulation of the transport fluid, typically a hydraulic fluid, is typically accomplished using a positive displacement pump. Position sensors are used to monitor the movement of the source in the conduit as well as its position within the shield. Disconnect units permit removal of the radiation source, as contained in the shield, from the system without accessing any other portions of the system.
摘要:
A method and apparatus for on-line DOI rebinning for LSO PET/SPECT to improve spatial resolution, for use in a hybrid Positron Emission Tomography (PET)/Single Photon Emission Computed Tomography (SPECT) system running in PET-mode. Data acquisition hardware is used to feed a detector pair coincidence event stream to an on-line rebinner. Gamma centroid location measurements are made by rastering assumed transaxial and radial head positions and the corresponding rebinning maps for optimal back-projected image resolution. Optimal positions are found by collecting a 64-bit list mode file, assuming a crystal position as the centroid for each of the heads, defining a sequence for varying the assumed positions, making the rebinning look-up tables, rebinning the list mode data, histogramming and reconstructing the image, assessing the image resolution, recording the best resolution number and the associated trial position variables, repeating these on the next trial variable set.
摘要翻译:用于LSO PET / SPECT的在线DOI重组以提高空间分辨率的方法和装置,用于以PET模式运行的混合正电子发射断层扫描(PET)/单光子发射计算机断层扫描(SPECT)系统。 数据采集硬件用于将检测器对重合事件流馈送到在线重组器。 伽马重心位置测量是通过对假设的横轴和径向头部位置以及相应的重新组合图进行掠夺来实现最佳背投影图像分辨率。 通过收集64位列表模式文件,假设晶体位置为每个头的质心,定义用于改变假定位置的序列,使重新排列查找表,重新列出列表模式数据,找到最佳位置, 直方图和重建图像,评估图像分辨率,记录最佳分辨率数字和相关联的试验位置变量,在下一个试验变量集中重复这些变量。
摘要:
A system identifies when received packets are lost at a node in a multi-node processing chain. The system processing chain may include a gantry interface module for receiving coincident event data from a PET (Positron Emission Tomography) detector array, a DMA (direct memory access) rebinner card, and a transmission line coupled between the gantry interface module and the DMA card. FPGA and FIFO elements in each processing portion receive packets that may be lost if there is insufficient FIFO capacity. Lost packets are marked, discarded, and counted. At specified intervals, set in accordance with a threshold number of packets received a lost tally data packet is generated that includes count information for lost packets. The lost tally data packet is forwarded downstream when sufficient storage capacity exists.
摘要:
A method and apparatus for producing radioactive transmission measurements to form multi-dimensional attenuation correction data with a point source of radiation, such as required in positron emission tomography applications. This involves the passing of the point source proximate the face of each of the tomograph units for the formation of a 3-D image, or a selected portion of the tomograph units for a 2-D image. As such, attenuation data, transmission data, detector performance data, etc., can be obtained. This point source of radiation, in one embodiment, is rapidly circulated through a conduit that passes across each detector face under the influence of a transport fluid in, for example, an oscillatory motion to achieve a selected radiation field whereby calculation of transmission measurements within a body positioned within the tomograph scanner is achieved. When not being circulated, the radiation source is held within a shield. In another embodiment, the point source is a CT device. In a further embodiment, a single photon source is used in association with an ECAT ART having two oppositely disposed detector banks. One point source is provided for association with each detector bank. Each point source is capable of axial movement with respect to the detector banks, with the entire apparatus including the detector banks and the point sources being rotatable. Collimators are provided for each point source, the collimators and the point source being fixed with respect to each other, thus reducing the effects of dead-time during a transmission scan typically caused by the point source moving behind a collimator.
摘要:
A 3-dimensional projection system (10) for the rapid back projection of multi-ring Positron Emission Tomography (PET) scan data composed of planes (44) of two-dimensional data defining individual Lines Of Response (LOR) (42) into a plurality of image voxels for three-dimensional display on a video screen. The projection system (10) of the preferred embodiment is a Very Large Scale Integration (VLSI) based architecture which will support forward and back projection for a 3-dimensional image detected by a multi-ring PET scanner. A selected number of processing engines (20) are included for forward projection and back projection, the number of engines (20) being inversely proportional to the projection time.
摘要:
A system identifies when received packets are lost at a node in a multi-node processing chain. The system processing chain may include a gantry interface module for receiving coincident event data from a PET (Positron Emission Tomography) detector array, a DMA (direct memory access) rebinner card, and a transmission line coupled between the gantry interface module and the DMA card. FPGA and FIFO elements in each processing portion receive packets that may be lost if there is insufficient FIFO capacity. Lost packets are marked, discarded, and counted. At specified intervals, set in accordance with a threshold number of packets received a lost tally data packet is generated that includes count information for lost packets. The lost tally data packet is forwarded downstream when sufficient storage capacity exists.
摘要:
A patient bed drive mechanism, under control of a processor, is capable of continuously moving a patient bed through the a TOF-PET detector array having a stationary field of view (FOV) for a distance in excess of the physical extent of an axis of the array FOV. A direct memory access (DMA) rebinner card is coupled to the detector array to receive therefrom a stream of TOF-PET coincidence event data during the extent of movement of the bed. Image projection data are generated in real time from the acquired stream of TOF-PET coincidence event data via the DMA card.
摘要:
According to a preferred embodiment, the invention provides a method for extracting internal organ motion from positron emission tomography (PET) coincidence data, the method comprising the following steps: generating a data stream of PET coincidence data using the list mode capability of a PET scanner; dividing the data stream into time frames of a given length; computing a histogram A(i, t) of an axial coincidence distribution for a set of time frames; computing the axial center of mass z(t) for each of the time frames in the set of time frames based on the histogram A(i, t); transforming z(t) into the frequency domain; determining either the frequency contribution caused by respiratory motion, given by fresp, or the frequency contribution caused by heart contractions, given by fcard and Δf, identified in the frequency spectrum |Z(f)|; and carrying out further processing of Z(f) leading to curves zresp(t) and zcard(t) with which a gating sequence is established.