Koninklijke Philips Corporation N.v.

Picker International, Inc.

Addressograph Multigraph Corporation

Marconi Medical Systems, Inc.

Koninkluke Philips N.v.

Philips Intellectual Property & Standards Gmbh

Jerome John Griesmer

Thomas Leroy Laurence

Barry D Kline

Sharon Xiaorong Wang

Daniel Gagnon

Gordon D DeMeester

Michael Andrew Morich

Volkmar Schulz

Carsten Degenhardt

Zhiqiang Hu

Marc Anthony Chappo

Torsten Solf

Steffen Renisch

Thomas Blaffert

Andreas Thon

Leonard F Plut

Steven E Cooke

Hugh T Morgan

Donald E Negrelli

Ralph Brinks

Bjoern Weissler

Jeffrey Allan Kolthammer

Kevin Patrick McMahon

Zhongmin Lin

Dane Pittock

Nathan Serafino

Lynn W Krebs

Gordon D Demeester

Sharon X Wang

Torsten J Solf

A medical nuclear imaging system () and method () generate smooth energy histograms. Radiation events are detected by a plurality of detectors (), the radiation events localized to a plurality of pixels of the detectors (). The energy levels of the detected radiation events are estimated and the estimated energy levels are scaled with scaling parameters that scale the energy centroids of the plurality of pixels to target values differing by offsets around a common target value, the target values differing with spatial location of the plurality of pixels. Target value offsets are removed from the scaled energy levels and the detected radiation events are combined into an energy histogram using the energy levels with the target value offsets removed.

Histogram smoothing in positron emission tomography (PET) energy histograms

An imaging system () includes a detector array () with a ring () with a first layer () that detects gamma radiation and X-ray radiation and a second layer (N) that detects only gamma radiation, wherein the first and second layers are concentric closed rings. A method includes detecting gamma radiation with a first layer of a dual layer detector in response to imaging in PET mode, detecting gamma radiation with a second layer of the dual layer detector in response to imaging in PET mode, and generating PET image data with the radiation detected with the first and second layers. The method further includes detecting X-ray radiation with the first layer in response to imaging in CT mode and generating CT image data the radiation detected with the first layer. The method further includes displaying the image data. The imaging system allows a single gantry for both PET/CT imaging.

Hybrid PET / CT imaging detector

A positron emission tomography (PET) system () and method () classifies gamma events. At least one processor () is programmed to receive event data for a plurality of scintillation events corresponding to gamma events. The gamma events are generated by gamma photons from a region of interest (ROI) (). The gamma events of the event data are classified into a plurality of classifications. The classifications distinguish between single-crystal gamma events and multi-crystal gamma events.

High spatial resolution mode solid state positron emission tomography (PET) scanner

A detector maintains thermal stability between two different operating modes. The detector includes at least one controller which sets the detection sensitivity of the detector to a level disabling the detection of gamma photons. The controller further controls a heat generator to maintain the temperature of the detector at a predetermined temperature. The predetermined temperature is the steady state temperature of the detector when the detection sensitivity of the detector is set to a level enabling the detection of gamma photons. A method for maintaining thermal stability of a detector between two different operating modes is also provided. Approaches are also disclosed for normalize acquired imaging data during image reconstruction using dark current-dependent normalization factors.

Temperature stability for a digital positron emission tomography (PET) detector

A time of flight positron emission tomography apparatus () includes a detector (), a data acquisition system (), a coincidence system () and a reconstructor (). Various elements of an imaging chain influence the temporal resolution of the system () so that positron data collected along different lines of response is characterized by different temporal resolutions. The different temporal resolutions are used to estimate the positions of detected events along their respective lines of response.

Method and system for improved TOF PET reconstruction

A nuclear imaging system includes a crystal identification system which receives a flood image which includes a plurality of peaks, each peak responsive to radiation detected by a corresponding scintillator crystal. A crystal identification processor partitions the flood image into a plurality of candidate regions with a watershed segmentator implementing a watershed algorithm. The candidate regions are linked in an adjacency graph, and then classified as background or relevant, where relevant regions contain a peak within the watershed lines. The regions are then assigned to a crystal according to an objective function and an assignability score. A calibration processor maps the peaks to a rectangular grid.

Automated crystal identification achieved via watershed segmentation

A nuclear imaging system () includes a crystal identification system () which receives a flood image () which includes a plurality of peaks, each peak responsive to radiation detected by a corresponding scintillator crystal. A crystal identification processor () partitions the flood image () into a plurality of regions (), each region being masked to correspond to one of an array of nuclear detectors. A model image () is generated in which the at least one Gaussian models represents the identified peaks. Misidentified peaks in the model image () in which locations of the peaks in the flood image () differ from the corresponding scintillator crystal are determined and the locations of the misidentified peaks in the flood image () are corrected. A calibration processor () corrects geometric distortions in acquired projection data according to the corrected peaks.

Automated crystal identification achieved via modifiable templates

In nuclear imaging, when a gamma ray strikes a scintillator, a burst of visible light is created. That light is detected by a photodetector and processed by downstream electronics. It is desirable to harness as much of the burst of light as possible and get it to the photodetector. In a detector element (), a first reflective layer () partially envelops a scintillation crystal (). The first reflective layer () diffuses the scintillated light. A second reflective layer () and a support component reflective layer () prevent the light from leaving the scintillation crystal () by any route except a light emitting face () of the scintillator (). In another embodiment, a light concentrator () is coupled to the scintillator () and channels the diffuse light onto a light sensitive portion of a photodetector (). The reflective layers () and the concentrator () ensure that all or nearly all of the light emitted by the scintillator () is received by the photodetector ().

Reflector and light collimator arrangement for improved light collection in scintillation detectors

In a hybrid PET-MR system, PET detector elements () are added in the bore (), in close proximity to the gradient coils (). Fluid coolant is supplied to transfer heat from the PET detector elements (). Thermal insulation () insulates the fluid coolant and the PET detector elements () from the gradient coils (). In some embodiments, a first coolant path () is in thermal communication with the electronics, a second coolant path () is in thermal communication with the light detectors, and a thermal barrier () is arranged between the first and second coolant paths such that the first and second coolant paths can be at different temperatures (T, T). In some embodiments a sealed heat pipe () is in thermal communication with a heat sink such that working fluid in the heat pipe undergoes vaporization/condensation cycling to transfer heat from the detector elements to the heat sink.

Thermally stabilized pet detector for hybrid PET-MR system

A positron emission tomography (PET) detector ring comprising: a radiation detector ring comprising scintillators () viewed by photomultiplier tubes (); and a magnetic field shielding enclosure () surrounding sides and a back side of the annular radiation detector ring so as to shield the photomultiplier tubes of the radiation detector ring. Secondary magnetic field shielding (') may also be provided, comprising a ferromagnetic material having higher magnetic permeability and lower magnetic saturation characteristics as compared with the magnetic field shielding enclosure, the second magnetic field shielding also arranged to shield the photomultiplier tubes of the radiation detector ring. The secondary magnetic field shielding may comprise a mu-metal. The PET detector ring may be part of a hybrid imaging system also including a magnetic resonance (MR) scanner, the PET detector ring being arranged respective to the MR scanner such that a stray magnetic field from the MR scanner impinges on the PET detector ring.

Magnetic shielding for a PET detector system

A method for calibrating an imaging system includes coincident detecting scatter radiation events from a calibration source located within a bore of the imaging system. The scatter radiation events are subsequently used to compute calibration time offsets for each detector channel in the imaging system. Each detector channel is then calibrated with respective calibration time adjustments.

Achieving accurate time-of-flight calibrations with a stationary coincidence point source

A system reverses degraded energy resolution of semiconductor radiation detection elements () which are used in a radiation detector assembly. A means () identifies semiconductor elements which exhibit degraded energy resolution as compared to an initial level of energy resolution after application of the forward bias. A means () restores the degraded semiconductor elements to the initial level of energy resolution by applying the reverse bias. A heater () accelerates the restoration process by supplying an elevated ambient temperature. A screening means () screens new semiconductor elements to identify the elements which are susceptible to degradation. A forward bias is applied by a forward bias means () to induce the degradation. A heater () increases an ambient temperature to accelerate the performance degradation in the new semiconductor elements. The identified degradable elements are treated with a reverse bias prior to installation in the detector.

Method and apparatus for reversing performance degradation in semi-conductor detectors

A nuclear imaging apparatus includes a radiation detector comprising an array ( ) of solid state detector elements ( ) responsive to incident gamma radiation by emitting a current spike. A pixel correction processor ( ) detects defective detector elements in the array and a flood correction circuit ( ) corrects detected radiation events ( ) based on sensitivity differences between a plurality of groupings of detector elements in the array. A reconstruction processor ( ) reconstructs an image representation from the corrected radiation events ( ).

Fault-tolerant detector for gamma ray imaging

A subject ( ) is disposed adjacent a detector array ( ) for the purposes of nuclear imaging. The subject ( ) is injected with a radioactive isotope ( ) and &ggr;-ray emissions indicative of nuclear decay are detected at the detector array ( ). P-ASIC ( ) preamplifier circuits are complex low-noise integrated circuits which dissipate a considerable amount of power (300-500 mW each). These components account for most of the dissipated power on the daughter cards ( ). In order to facilitate the cooling of these electrical components, they are mounted on circuit boards ( ) that are arranged parallel to each other extending perpendicularly away from the detector array ( ). This provides channels between the boards through which cooling air is drawn by an array of fans ( ).

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Mentor, OH, United States of America

Jerome John Griesmer