Siemens Medical Solutions USA, Inc.

Siemens Aktiengesellschaft

Cintilight, LLC

Ronald Grazioso

Markus Vester

Nan Zhang

Debora Henseler

Matthias J Schmand

Philipp Braeuninger-Weimer

Chad E Seaver

James Luke Corbeil

Charles L Melcher

Mehmet Aykac

Christian J Michel

A Andrew Carey

Maurizio Conti

Lars Aldon Eriksson

Larry Byars

Wolfgang Renz

Ralf Ladebeck

Hubertus Fischer

Ronald Nutt

Peter Carl Cohen

Piotr Szupryczynski

Simon Jelley

Johannes Breuer

Harold E Rothfuss

Sanghee Cho

Robert E Nutt

Bernd J Pichler

Guenter Schnur

Günter Schnur

Florian Bauer

Marcus Vester

Mathias J Schmand

A positron emission tomography (PET) scanner may include a plurality of gamma radiation detector modules arranged to form a detector ring. Each detector module may include an array of elongated scintillation crystals. With respect to the detector ring, each elongated scintillation crystal includes a proximal end-face, two axially oriented lateral faces, two transaxially oriented lateral faces, and a distal end-face radially oriented into the detector ring to receive a gamma photon. An array of photosensors is positioned along a first of the axially oriented lateral faces of each elongated scintillation crystal to detect scintillation photons. A reflective material is positioned on the proximal end-face, the distal end-face, the transaxially oriented lateral faces, and a second of the axially oriented lateral faces of each elongated scintillation crystal to internally reflect scintillation photons. In various embodiments, a dual-channel processing circuit provides distinct timing and energy signals from the photosensors.

Lateral crystal photodiode readouts and switched diode networks for processing nuclear events

A positron emission tomography (PET) scanner includes a plurality of gamma radiation detector modules arranged to form a detector ring. Each detector module includes an array of scintillator detectors. Each scintillator detector comprises a monolithic scintillation crystal and a plurality of photodetector arrays, such as silicon photomultipliers (SiPMs). A photodetector array is positioned on at least two nonparallel faces of each scintillation crystal. In some examples, a photodetector array is positioned on each of three orthogonal faces of each scintillation crystal.

Scintillator detectors and methods for positron emission tomography

Apparatuses, computer-readable mediums, and methods are provided. In one embodiment, a positron emission tomography ('PET') detector array is provided which includes a plurality of crystal elements arranged in a two-dimensional checkerboard configuration. In addition, there are empty spaces in the checkerboard configuration. In various embodiments, the empty spaces are filled with passive shielding, transmission source assemblies, biopsy instruments, surgical instruments, and/or electromagnetic sensors. In various embodiments, the crystal elements and the transmission source assemblies simultaneously perform emission/transmission acquisitions.

PET scanner with emission and transmission structures in a checkerboard configuration

APD-based PET modules are provided for use in combined PET/MR imaging. Each module includes a number of independent, optically isolated detectors. Each detector includes an array of scintillator (e.g. LSO) crystals read out by an array of APDs. The modules are positioned in the tunnel of a MR scanner. Simultaneous, artifact-free images can be acquired with the APD-based PET and MR system resulting in a high-resolution and cost-effective integrated PET/MR system.

Combined PET/MR imaging system and APD-based PET detector for use in simultaneous PET/MR imaging

An automated blood sampling system for PET imaging applications that can be operated in or very near to the field of view (FOV) of an MR scanner, such as in a combined MR/PET imaging system. A radiation detector uses APDs (avalanche photo-diodes) to collect scintillation light from crystals in which the positron-electron annihilation photons are absorbed. The necessary gamma shielding is made from a suitable shielding material, preferably tungsten polymer composite. Because the APDs are quite small and are magnetically insensitive, they can be operated in the strong magnetic field of an MR apparatus without disturbance.

MR-compatible blood sampling system for PET imaging applications in combined PET/MR imaging system

A representative positron emission tomography (PET) system includes a positron emission tomography detector having one or more silicon photomultipliers that output silicon photomultipliers signals. The PET system further includes a calibration system that is electrically coupled to the silicon photomultipliers. The calibration system determines a single photoelectron response of the silicon photomultipliers signals and adjusts a gain of the silicon photomultipliers based on the single photoelectron response.

Systems and methods for calibrating a silicon photomultiplier-based positron emission tomography system

A system and method is provided for determining depth of interaction (DOI) information. The system and method includes a detector configured to generate DOI information as a result of radiation emitted from a radiation source. The system and method further includes a plurality of scintillator pixels forming a block, wherein the plurality of scintillator pixels have a first portion and a second portion. A first medium distributed in an alternating pattern of coupling and separation between each of the scintillator pixels in a first portion or second portion of the block is also provided. A plurality of sensors for detecting scintillation events across the plurality of scintillators based on the alternating pattern of coupling and separation between each of the scintillator pixels, wherein DOI information is provided by a position profile of the block, and an image processor for generating a 3 dimensional image from the DOI information are also included.

System and method for providing depth of interaction detection using positron emission tomography

A system and method are provided for determining the onset of gamma interactions for positron emission tomography (PET) imaging more accurately than with existing techniques. The timing of a sequence of primary trigger events is obtained and used to determine a weighted combination, which mixes the timing information from the various primary trigger events to compute an overall event trigger timing with improved time resolution. Numerical simulations demonstrate that the invention improves time resolution by approximately 10% over state-of-the-art methods. This improved time resolution directly benefits the imaging performance of the PET scanner, especially in time-of-flight (TOF) mode, where a high time resolution directly translates to a reduction in image noise at the same dose&#x2014;or, alternatively, a reduction of dose to the patient or scan time for the same image quality.

System and method for improving detection of gamma interactions in a positron emission tomography system

Systems and methods for correcting output signals from non-linear photosensors, specifically silicon photomultipliers (SiPMs). SiPMs are used in a PET detector to readout light emissions from LSO scintillator crystals. The non-linear output of the SiPM can distort and compress the energy spectrum which is crucial in PET imaging. The non-linearity effect for inter-crystal scattered events can place an energy event outside of the PET detector energy window, resulting in a rejected event. Systems and methods to correct the SiPM non-linearity for inter-crystal scattered events, so as to be able to obtain the proper energy event and produce an accurate medical image, are disclosed.

Energy correction for one-to-one coupled radiation detectors having non-linear sensors

An apparatus and method to decrease light saturation in a photosensor array and increase detection efficiency uses a light distribution profile from a scintillator-photodetector geometry to configure the photosensor array to have a non-uniform sensor cell pattern, with varying cell density and/or varying cell size and shape. A solid-state photosensor such as a SiPM sensor having such a non-uniform cell structure realizes improved energy resolution, higher efficiency and increased signal linearity. In addition the non-uniform sensor cell array can have improved timing resolution due to improvements in statistical fluctuations. A particular embodiment for such photosensors is in PET medical imaging.

Providing variable cell density and sizes in a radiation detector

The present invention is a Silicon PhotoMulitplier comprising a plurality of photon detection cell clusters each comprising a plurality of avalanche photodiodes connected in parallel, so that the output of each avalanche photodiode is summed together and applied to a cell cluster output. Each of the plurality of cell cluster outputs is connected to one of a plurality of cluster readout circuits, each of which includes an analog to digital converter that converts an analog representation of the total energy received by a photon detection cell cluster to a digital energy signal. A SiPM Pixel reader circuit is connected to the plurality of cluster readout circuits and configured to generate an overall pixel output by digital processing the plurality of digital energy signals received from the plurality of photon detection cell clusters by way of the plurality of cluster readout circuits. The SIPM pixel reader circuit also receives digital signals representative of timing triggers and the total energy received by a specific photon detection cell cluster and generates an overall SiPM energy signal and overall timing trigger in response to the signals received from the plurality of cluster readout circuits.

SiPM photosensor with early signal digitization

The present invention is a photodetector including improved photosensors configured of an array of small (sub-millimeter) high-density avalanche photodiode cells utilized to readout a single scintillator. Each photosensor comprises a plurality of avalanche photodiodes cells arranged in an (n&#xd7;n) array of avalanche photodiode cells (where, n&#x3e;1) that are coupled to a single scintillation crystal. The overall (n&#xd7;n) array area as the photosensor is the same as the area of a face of the scintillator and each avalanche photodiode cell has a surface area that is not greater than one square millimeter. The photosensor is also configured to facilitate reading the output of each avalanche photodiode cell in the array. By reading out each small avalanche photodiode cell independently, the noise and capacitance are minimized and thereby provide a more accurate determination of energy and timing.

High density, proportional-mode, APD arrays for individual scintillator readout in PET applications

A phoswich device for determining depth of interaction (DOI) includes a first scintillator having a first scintillation decay time characteristic, a second scintillator having a second scintillation decay time characteristic substantially equal to the first scintillation decay time, a photodetector coupled to the second scintillator, and a wavelength shifting layer coupled between the first scintillator and the second scintillator, wherein the wavelength shifting layer modifies the first scintillation decay time characteristic of the first scintillator to enable the photodetector to differentiate between the first decay time characteristic and the second decay time characteristic. The phoswich device is particularly applicable to positron emission tomography (PET) applications.

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Knoxville, TN, United States of America

Ronald Grazioso