Abstract: Signals generated by radiation sensors can be encoded to reduce the number of cables needed to transport information from a nuclear imaging apparatus to a processor for reconstruction. For example, signals from 16 radiation sensors can be encoded into three signals: T (top), L (left), and E (energy). This method of encoding signals can be capable of substantially reducing the number of signals, thereby reducing costs. In addition, reducing the number of signals could improve system timing performance by eliminating cable time-skew and facilitate the filter design by downgrading the circuit accuracy requirements such as group-delay error and filter signal skews.

Abstract: 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×n) array of avalanche photodiode cells (where, n>1) that are coupled to a single scintillation crystal. The overall (n×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.

Abstract: 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×n) array of avalanche photodiode cells (where, n>1) that are coupled to a single scintillation crystal. The overall (n×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.

Abstract: A method, process and apparatus for compensating for changes to the gain of photo detectors in a nuclear imaging apparatus is disclosed. Specifically, embodiments detect positron annihilation event pulses using photo detectors. Changes to the gain of the photo detectors are compensated for by determining the relationship of a detected event pulse peak with a target event pulse peak. Based on the difference between these two peaks, a corrected gain is determined in a closed-loop control system. The corrected gain can be used to compensate for temperature changes that can affect the gain of the photo detectors.

Abstract: 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.

Abstract: A simple, low cost circuit with only passive components, and thus low power consumption, is provided for baseline restoration of an AC coupled signal. The circuit includes a passive network of diodes arranged in a star configuration and an RF-transformer. A differential signal strategy may be employed by including a differential amplifier at the input and output of the passive network.

Abstract: An emission tomography detector module and an emission tomography scanner are disclosed. In at least one embodiment, the emission tomography detector modules includes a scintillator to capture an photon, the scintillator emitting a scintillating light on capturing the photon; a first type of solid-state photodetector to detect the scintillating light; and a second type of solid-state photodetector to detect the scintillating light, wherein the first type of solid-state photodetector and the second type of solid-state photodetector are different with respect to a detecting property.

Abstract: A phantom and method are provided for co-registering a magnetic resonance image and a nuclear medical image. The phantom includes a first housing defining a first chamber configured to receive a magnetic resonance material upon which magnetic resonance imaging can be performed in order to produce the magnetic resonance image. The phantom also includes three or more second housings configured to be attached to the first housing, where the second housings each define a second chamber configured to receive a radioactive material upon which nuclear imaging can be performed in order to produce the nuclear medical image and upon which the magnetic imaging can be performed in order to produce the magnetic resonance image. The first chamber has a volumetric capacity that is larger than a volumetric capacity of each second chamber.

Abstract: Medical imaging may be accomplished with a high photoconductive gain at a relatively low operating voltage by employing a black silicon photodetector and integrating CMOS components with elements of the photodetector.

Abstract: A method, process and apparatus for compensating for changes to the gain of photo detectors in a nuclear imaging apparatus is disclosed. Specifically, embodiments detect positron annihilation event pulses using photo detectors. Changes to the gain of the photo detectors are compensated for by determining the relationship of a detected event pulse peak with a target event pulse peak. Based on the difference between these two peaks, a corrected gain is determined in a closed-loop control system. The corrected gain can be used to compensate for temperature changes that can affect the gain of the photo detectors.

Abstract: A simple, low cost circuit with only passive components, and thus low power consumption, is provided for baseline restoration of an AC coupled signal. The circuit includes a passive network of diodes arranged in a star configuration and an RF-transformer. A differential signal strategy may be employed by including a differential amplifier at the input and output of the passive network.

Abstract: A medical device with a high voltage connection line for carrying a high DC supply voltage has a control unit generating said high DC supply voltage which is fed through a first AC block unit to said high voltage connection line and generating a digital control signal fed through a first AC coupling unit to said high voltage connection line, and a remotely located unit a second AC block unit coupled to said high voltage connection line for receiving said high DC supply voltage and a second AC coupling unit coupled to said high voltage connection line for receiving said digital control signal.

Abstract: A method is disclosed for stabilizing the gain of a PET detection system with a cooling unit. The method includes determining the temperature of at least one component of the PET detection system, comparing the actual gain with a reference value, and actuating the cooling unit to influence the temperature such that the gain tends to the reference value. In at least one embodiment, the reference value is determined by determining the temperature of the at least one component during a test measurement, determining the gain during the test measurement, determining a functional dependence of the gain on the temperature, and selecting the reference value based on the gain to be stabilized. Advantageously, in at least one embodiment the gain can be kept constant using the described method in a simple manner, with the influence of the temperature of the components being taken into account.

Abstract: 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.

Abstract: A medical device with a high voltage connection line for carrying a high DC supply voltage has a control unit generating said high DC supply voltage which is fed through a first AC block unit to said high voltage connection line and generating a digital control signal fed through a first AC coupling unit to said high voltage connection line, and a remotely located unit a second AC block unit coupled to said high voltage connection line for receiving said high DC supply voltage and a second AC coupling unit coupled to said high voltage connection line for receiving said digital control signal.

Abstract: A system for multiplexing photodetector signals from a scintillation detector. The system includes a detector module having a number of scintillator blocks, each scintillator block having a number of photosensors, and a number of multiplexing circuits. Each multiplexing circuit includes a number of inputs, a signal polarity inverter and at least one differential output attached to the signal polarity inverter. The multiplexing system inverts the polarity of preselected signals from the photosensors and selectively combines signals of different polarities to calculate event positioning and total energy.

Abstract: A scintillation detector including one or more photomultiplier tubes, a scintillation block optically attached to the photomultiplier tubes, and a DC-coupled bleeder circuit combining outputs of dynodes of the photomultipliers to provide a DC-coupled dynode output together with a DC-coupled anode output of the photomultiplier tubes. The DC-coupled bleeder circuit includes a RF transformer. A positive high voltage supply also can be used together with a DC-coupled bleeder circuit for the anode outputs.

Abstract: A phantom and method are provided for co-registering a magnetic resonance image and a nuclear medical image. The phantom includes a first housing defining a first chamber configured to receive a magnetic resonance material upon which magnetic resonance imaging can be performed in order to produce the magnetic resonance image. The phantom also includes three or more second housings configured to be attached to the first housing, where the second housings each define a second chamber configured to receive a radioactive material upon which nuclear imaging can be performed in order to produce the nuclear medical image and upon which the magnetic imaging can be performed in order to produce the magnetic resonance image. The first chamber has a volumetric capacity that is larger than a volumetric capacity of each second chamber.

Abstract: A detector array including a plurality of scintillators for use in association with an imaging device. The detector array is provided for accurate determination of the location of the impingement of radiation upon an individual scintillator detector. An air gap is disposed between the scintillator elements, thereby increasing the packing fraction and overall sensitivity of the array. The amount of light transmitted down the scintillator element and the amount of light transmitted to adjacent elements is modified to optimize the identification of each element in a position profile map by adjusting the surface finish of the detector elements.

Abstract: A radiation detector having a fiber optic wedge with a plurality of parallel optical fibers is provided for yielding a more cost-effective radiation detector by reading out more scintillator elements or crystals per photodetector surface area. The fiber optic wedge provides a cost efficient method for increasing the number of scintillators that may be read out by a single position-sensitive photodetector of the radiation detector, such as a PET camera.