Abstract: A method of assessment of renal function by monitoring a time-varying fluorescence signal emitted from a fluorescent agent from within a diffuse reflecting medium with time-varying optical properties is provided that includes using a renal monitoring system comprising at least one light source, at least one light detector, at least one optical filter, and at least one controller to provide a measurement data set comprising a plurality of measurement entries, each measurement data entry comprising at least two measurements obtained at one data acquisition time from a patient before and after administration of the fluorescent agent.

Abstract: Techniques for calibrating a device having a stereoscopic camera are disclosed. According to an embodiment, the device calibrates the stereoscopic camera using a target provided by a mobile device. One or more zones each defining an area in a field of view of the calibrated stereoscopic camera are generated. The one or more zones are refined based on input provided by the mobile device.

Abstract: A method of assessment of renal function by monitoring a time-varying fluorescence signal emitted from a fluorescent agent from within a diffuse reflecting medium with time-varying optical properties is provided that includes using a renal monitoring system comprising at least one light source, at least one light detector, at least one optical filter, and at least one controller to provide a measurement data set comprising a plurality of measurement entries, each measurement data entry comprising at least two measurements obtained at one data acquisition time from a patient before and after administration of the fluorescent agent.

Abstract: Various methods and systems are provided for scatter correction in nuclear medicine imaging systems. In one embodiment, a method for NM imaging comprises acquiring, with a plurality of detectors, imaging data separated into a high energy window and a low energy window, removing photopeak photons from the imaging data in the low energy window to obtain a corrected scatter distribution, correcting the imaging data based on the corrected scatter distribution, and outputting a scatter-corrected image reconstructed from the corrected imaging data. In this way, fast and accurate scatter correction for CZT-based gamma cameras may be performed, and image quality as well as quantitative accuracy may be increased.

Abstract: An amplification circuit includes a first group of amplifiers including N first amplifiers, a second group of amplifiers including K second amplifiers, a first terminal, a second terminal, and a third terminal. Each of the N first amplifiers and each of the K second amplifiers includes an output. The second group of amplifiers is divided into a first subassembly of amplifiers and a second subassembly of amplifiers. The first subassembly includes M second amplifiers of the second group. The second subassembly includes K-M remaining second amplifiers of the second group. The first terminal is coupled to each output of the N first amplifiers and to a first radio frequency output terminal. The second terminal is coupled to each output of the M second amplifiers. The third terminal is coupled to each output of the K-M second remaining amplifiers and to a second radio frequency output terminal.

Abstract: A method of monitoring a time-varying fluorescence signal emitted from a fluorescent agent from within a medium with time-varying optical properties is provided that includes providing a measurement data set that includes a plurality of measurement entries that include at least two measurements obtained from a patient before and after administration of the fluorescent agent. The measurements may include one or more of: a DRex signal detected by an unfiltered light detector during illumination by excitatory-wavelength light from first region adjacent to the diffuse reflecting medium; a Flr signal detected by a filtered light detector during illumination by excitatory-wavelength light; and a DRem signal detected by the unfiltered light detector during illumination by emission-wavelength light.

Abstract: A sensor head is provided. In any of the various aspects of the invention, the sensor head has a housing enclosing at least two light sources configured to deliver light to a patient and comprising a blue LED first light source that delivers light at an excitatory wavelength and a green LED second light source, and at least one light detector configured to detect light at an emission wavelength from the patient. The sensor is useful for non-invasive monitoring of fluorescent tracers agents.

Abstract: A method and apparatus are provided for positron emission imaging to correct a recorded energy of a detected gamma ray, when the gamma ray is scattered during detection. When scattering occurs, the energy of a single gamma ray can be distributed across multiple detector elements—a multi-channel detection. Nonlinearities in the detection process and charge/light sharing among adjacent channels can result in the summed energies from the multiple crystals of a multi-channel detection deviating from the energy that would be measured in single-channel detection absent scattering. This deviation is corrected by applying one or more correction factors (e.g., multiplicative or additive) that shifts the summed energies of multi-channel detections to agree with a known predefined energy (e.g., 511 keV). The correction factors can be stored in a look-up-table that is segmented to accommodate variations in the multi-channel energy shift based on the level of energy sharing.

Abstract: A method of monitoring a time-varying fluorescence signal emitted from a fluorescent agent from within a medium with time-varying optical properties is provided that includes providing a measurement data set that includes a plurality of measurement entries that include at least two measurements obtained from a patient before and after administration of the fluorescent agent. The measurements may include one or more of: a DRex signal detected by an unfiltered light detector during illumination by excitatory-wavelength light from first region adjacent to the diffuse reflecting medium; a Flr signal detected by a filtered light detector during illumination by excitatory-wavelength light; and a DRem signal detected by the unfiltered light detector during illumination by emission-wavelength light.

Abstract: A method for photosensor signal processing includes carrying out, by measuring a combination of readout channels of a direction e with linearly increasing and linearly decreasing signal strength, a linear coding in at least one e-direction. The linearly increasing and linearly decreasing signal strengths of readout channels of the direction e, which are respectively used for the linear coding, are multiplied by each other. The linear coding satisfies the following edge condition: Q1(e)=c1·ec2+c3, Q2(e)=c4·ec5+c6, c1=const. ?(0, ?), c4=const. ?(??, 0), c3, c6=const. ?(??, ?), and 0.5<c2; c5<1.5. Q1 denotes the charge of the output channel signal strengths increasing via the e-position, and Q2 denotes the charge of the output channel signal strengths decreasing via the e-position and the coding direction.

Abstract: A medical nuclear imaging system (10) and method (100) generate smooth energy histograms. Radiation events are detected by a plurality of detectors (14), the radiation events localized to a plurality of pixels of the detectors (14). 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.

Abstract: A system (10) and method for energy correction of positron emission tomography (PET) event data by at least one processor. Event data for a plurality of strike events corresponding to gamma events is received. Each strike event is detected by a pixel of a detector module (50) and includes an energy and a time. The energy of the strike events is linearized using an energy linearity correction model including one or more parameters. Clusters of the strike events are identified based on the times of the strike events, and sub-clusters of the clusters are identified based on the pixels corresponding to the strike events of the clusters. Energies of the sub-clusters are corrected using a first set of correction factors, and energies of clusters including a plurality of sub-clusters are corrected using a second set of correction factors.

Abstract: A medical diagnostic-imaging apparatus of an embodiment includes plural converters and processing circuitry. The converters output an electrical signal based on an incident radioactive ray. The processing circuitry identifies a first signal intensity that is a signal intensity corresponding to a peak of the number of the radioactive rays based on a relationship between a signal intensity of an electrical signal output from the convertor and the number of incident radioactive rays, for each of the converters. The processing circuitry identifies a second signal intensity that is a signal intensity corresponding to energy of a radioactive ray that has entered therein without scattering, based on a relationship between the signal intensity and the number of radioactive rays in a higher intensity than the first signal intensity.

Abstract: A method and system for acquiring a series of medical images includes a plurality of detectors configured to be arranged to acquire gamma rays emitted from a subject as a result of an advanced radionuclide administered to the subject and communicate signals corresponding to acquired gamma rays. A data processing system is configured to receive the signals from the plurality of detectors, determine double coincidence event dataset and a multiple coincidence event dataset, separate the multiple coincidence event dataset into at least one of a standard lines of response dataset and a nonstandard lines of response dataset, and apply a background correction to the double coincidence event dataset based on the non-standard lines of response dataset and/or the standard lines of response dataset to obtain a standard coincidence dataset.

Abstract: The proposed group of inventions relates to methods for depositing fluorescent coatings on screens, by which an image is detected and/or converted, in particular, to methods of forming a structured scintillator on the surface of a photodetector intended for the detection of X-ray or gamma radiation, hereinafter referred to as the detected radiation, and to devices for obtaining an X-ray image, or an image obtained by detection of gamma radiation, particularly to devices for X-ray mammography and tomosynthesis. A method for forming a structured scintillator on the surface of a pixelated photodetector, wherein according to embodiment 1, at least one structural element is formed directly on the surface of the photodetector, the material of which is deposited by using a two-axis or a three-axis means for discrete deposition of liquid or heterogeneous substances.

Abstract: A radiation detector provides improved time-resolution under consideration of an incident of a multiple scattering event. An individual comparator 11 extracts a pulse from the detection element 3a through a total circuit 12 and converts to the time data. In addition, each detection element 3a comprises the total circuit 12, that outputs the pulse totaling the output of each detection element 3a, and the total comparator 13 that converts the pulses output from the total circuit 12 to the time data. According to the aspect of the present invention, the time data suitable from each discriminated event is processed, so that the emission-time of fluorescence can be more accurately determined.

Abstract: A unit (33) for generating count images for separate energy windows generates main measured count images and auxiliary measured count images on the basis of gamma ray (6) count information measured by a detector head (10). A main measurement window direct ray count rate estimation unit (42) estimates a count rate for direct gamma rays in a main measurement energy window, doing so by subtracting a scattered gamma ray count rate for an auxiliary measurement energy window, which has been estimated from an auxiliary measured count image and detector response data by an auxiliary measurement window scattered ray count rate estimation unit (41), from the main measured count image.

Abstract: A method and apparatus to improve the measurement accuracy for ionizing radiation pulses when using large scintillator crystals that absorb their own scintillation light.

Abstract: The invention relates to a method for operating an electronic terminal (1.1-1.4) comprising an integrated image sensor (2.1-2.4) that has a large number of pixels, in particular for a mobile telephone. According to the invention, a dosage value of ionizing radiation striking the image sensor is determined by means of the image sensor (2.1-2.4). The invention further relates to a terminal that operates accordingly (e.g. a smart phone having a corresponding application program).

Abstract: A portable gamma camera includes a containment body (2), a scintillation measuring structure (3) housed in the containment body (2), a collimator (4) associated with the measuring structure (3), a display (5) positioned on the containment body (2) and an electronic controller unit (6), operating between the measuring structure (3) and the display (5) for generating on the display (5) images representing the radiation intercepted by the measuring structure (3).

Abstract: An electronic detector module includes an array of detection crystals that emits light in response to electromagnetic radiation, and at least one detector that detects the light emitted by the crystal array and that generates an output based on the light detected. The electronic detector module also includes a power sequencing circuit including an accelerometer that detects a position of the electronic detector module, and a control circuit that provides power to the electronic detector module based on the position.

Abstract: A method includes reducing structured artifacts in 3D volumetric image data, which is generated with reconstructed projection data produced by an imaging system (100), by processing the 3D volumetric image data along a z-axis (108) direction. The 3D volumetric image data includes structured artifacts which have high-frequency components in the z-axis direction, and lower-frequency compounds within the x-y plane.

Abstract: A radiation diagnosis apparatus, which employs a reduced number of data acquisition units while showing the same effect as that of the related art (PET, SPECT or x-ray CT) includes: a first radiation detector; a second radiation detector an inverter formed at an output terminal of the first radiation detector; a discriminator for receiving a common signal from the first and second radiation detector and outputting a control signal corresponding to the input common signal; and a data acquisition unit and indentifying an output signal of which detector of the first and second detectors the input signal is according to a polarity difference of the input signal, to provide a radiation diagnosis apparatus which employs a reduced number of data acquisition units while showing the same effect as that of the related art.

Abstract: A radiation imaging system includes a radiation imaging cassette and a console device. A communication mode between the cassette and the console device is switchable between a wired mode and a wireless mode. Due to shortage of a battery of the cassette, the communication mode is switched to the wired mode to start charging the battery and send image data from the cassette to the console device through a cable. The console device has first and second judging sections. The first judging section judges whether or not a charge level of the battery exceeds a predetermined threshold value. The second judging section judges whether or not radiography is in progress. If it is judged that the charge level of the battery exceeds the predetermined threshold value and the radiography is not in progress, a window that indicates permission for switching to the wireless mode is displayed on a monitor.

Abstract: Embodiments of radiographic imaging systems; radiography detectors and methods for using the same can include radiographic imaging array that can include a plurality of pixels that each include a photoelectric thin-film conversion element coupled to a conversion thin-film switching element. In certain exemplary embodiments, a radiographic imaging array can include a bias control circuit to provide a bias voltage to the photosensors for a portion of the imaging array, an address control circuit to control scan lines, where each of the scan lines is coupled to a plurality of pixels in the portion of the imaging array; and a signal sensing circuit connected to data lines, where each of the data lines is coupled to at least two pixels in the portion of the imaging array, where power of the bias control circuit, the address control circuit, and the signal sensing circuit is not removed simultaneously.

Abstract: Improved methods and apparatuses for inserting pedicle screws in accordance with embodiments of the present invention include an image correction algorithm. In various embodiments, an original image of a region of interest of a patient including a pedicle is created with an X-ray emitter and an X-ray detector. Due to the X-ray emitter not being aligned orthogonal to the X-ray detector, the original image will be skewed. Using a known location and orientation of the X-ray detector, a location and orientation of the X-ray emitter provided by a position monitoring system, and the original image, a processing system can execute the image correction algorithm to provide a corrected image to allow a surgeon to properly insert a pedicle screw along the axis of the pedicle while viewing an accurate corrected image in real time.

Abstract: A new system and method for medical image processing using a nonlinear recursive filter are disclosed. An input signal including two or more pulses received from a medical imaging system is sampled at a predetermined sampling rate. The maximum magnitude, i.e., peak, and/or the occurrence time of the maximum magnitude of the first pulse of the input signal is/are determined using a nonlinear recursive filter. Predicted magnitude values of the tail of the first pulse can be determined and subtracted from the input signal to correct for pileup before determining the maximum magnitude and/or occurrence time of the next pulses. A medical image can be reconstructed using the determined maximum magnitudes and/or the occurrence times of the maximum magnitudes of the pulses of the input signal. The nonlinear recursive filter can be implemented using one or more look-up tables.

Abstract: Techniques for utilizing an infrared illuminator, an infrared camera, and a projector to create a virtual 3D model of a real 3D object in real time for users' interaction with the real 3D object.

Abstract: A method, including: determining a line of response for an imaging apparatus, the line of response being defined by respective locations of a pair of detector crystals of the imaging apparatus; defining an array of emission points corresponding to the determined line of response; determining, for each point in the array of emission points corresponding to the line of response, a solid angle subtended by surfaces of the pair of detector crystals that define the line of response; averaging the determined solid angles to generate an average solid angle; determining a depth of interaction factor dependent upon penetration of a gamma ray in the pair of detector crystals of the imaging apparatus; and calculating a geometric corrective factor for the determined line of response by multiplying a reciprocal of the average solid angle by the determined depth of interaction factor.

Abstract: The present disclosure relates to the correction of charge loss in a radiation detector. In one embodiment, correction factors for charge loss may be determined based on depth of interaction and lateral position within a radiation detector of a charge creating event. The correction factors may be applied to subsequently measured signals to correct for the occurrence of charge loss in the measured signals.

Abstract: A method of imaging a region of interest (ROI) in an object, the ROI having an axial extent greater than an axial FOV of a PET scanner. The method includes determining a number of overlapping scans of the PET scanner necessary to image at least the axial extent of the ROI, wherein each scan has a same axial length equal to the axial FOV, and each scan overlaps an adjacent scan by a predetermined overlap percentage of the axial length of each scan. The method includes determining a total amount of excess scanning length of the scans based on the number, the axial extent of the ROI, and the axial FOV, and determining a new overlap percentage so that a new total amount of excess scanning length is zero.

Abstract: Determining the position of a radioactive source in a PET system. Detecting a scatter coincidence event characterized by a full-energy photon detected at a first detector and partial-energy photon at a second detector. Measuring the arrival time difference between the partial energy photon and the full energy photon. Measuring the energy of the partial-energy photon. Determining a scattering point as a function of the position of the first detector, the position of the second detector, the energy of the partial-energy photon, the energy of an unscattered photon, the mass of a scattering electron, and the speed of light. Determining the position of a radioactive PET source along a line between the scatter point and the first detector as a function of the distance between scatter point and the first detector, the distance between scatter point and the second detector, and the measured time difference.

Abstract: Clearly notifying that a setting error of an imaging plane of a radiation image detector is on the increase. For a radiation image detector having an imaging plane with pixels, disposed in a two-dimensional matrix, for storing charges by receiving radiation according to an amount of radiation received and used to receive radiation transmitted through the same subject each time the detector is shifted and changed in position along a predetermined shift axis, a setting error of the imaging plane, i.e., an inclination of the two-dimensional matrix with respect to the shift axis or the like is detected a plurality of times with the passage of time and, when a fluctuation range of a plurality of setting errors so detected exceeds a predetermined acceptable range, an indication or an alarm so indicating is given.

Abstract: Example embodiments are directed to a method of correcting attenuation in a magnetic resonance (MR) scanner and a positron emission tomography (PET) unit. The method includes acquiring PET sinogram data of an object within a field of view of the PET unit. The method further includes producing an attenuation map based on a maximum likelihood expectation maximization (MLEM) of a parameterized model instance and the PET sinogram data.

Abstract: A radiation signal-processing unit including a position identifying device for identifying an incident radiation position in a radiation detector; a count data-memory device for storing positional information outputted from the position identifying device, a count ratio-calculation device for calculating a count ratio based on the positional information stored in the count data-memory device, a reference count ratio-memory device for memorizing a reference count ratio as the count ratio calculated under a state where fluorescence to be detected does not overlap each other temporally, and a correction instruction device for reading the reference count ratio from the reference count ratio-memory device and comparing the ratio with the count ratio, thereby instructing execution of correction of a radiation generating position to the position identifying device.

Abstract: A projector has: light source (1R, 1G, 1B); a light modulation unit (6) that modulates a light emitted from the light source based on image signals; a display control unit (41) that outputs the image signals including main cyclic image signals to the light modulation unit, and controls the display thereof; a projection unit (7) that projects the image based on the light modulated by the light modulation unit; and an imaging unit (40) that captures an image to be displayed based on the light projected from the projection unit, and the display control unit inserts a correction image signal for projecting a correction image, which is visually recognized as a uniform white or gray screen when time integration is performed, between the cyclic main image signals.

Abstract: A first ?-ray generating in a body, caused by a PET pharmaceutical, and a second ?-ray emitted from a ?-ray source and transmitting through the body are detected with a radiation detector. The emission image information (E image information), E0, E1 and E2, at each of patient motion phases, 0, 1 and 2, which divided a respiration period, are prepared by using information obtained from the detected first ?-ray. The transmission image information (T image information), T0, T1 and T2, at each of patient motion phases, 0, 1 and 2, respectively, are prepared, by using information obtained from the detected second ?-ray. Relative displacements, ([F10], [F20]), are determined by superimposing, on T image information T0, other T image information, T1 and T2. The E image information, E1, E2, are superimposed on the E image information E0, by using this relative displacement.

Abstract: The present invention relates to a system and method for compensating for anode gain non-uniformity in a Multi-anode Position Sensitive Photomultiplier Tube (PS-PMT), in which a compensation unit is disposed between the multi-anode position sensitive photomultiplier tube and a position detection circuit unit and configured to uniform a current signal inputted to the position detection circuit unit, thereby compensating for anode gain non-uniformity. In accordance with the present invention, the compensation unit for changing resistance is used. Accordingly, there is an advantage in that the gain non-uniformity of each of the anodes of the PS-PMT can be compensated for. Furthermore, the gain non-uniformity of each of the anodes of the PS-PMT is compensated for by changing resistance values of the variable resistances of the compensation unit. Accordingly, there is an advantage in that the interaction positions of gamma rays can be calculated more precisely.

Abstract: The CT imaging system optimizes its image generation by substantially reducing artifacts caused by a known amount of readout time lag in the X-ray detectors or data acquisition system. Although each detector row takes the same amount of time to read out the signals, the time lag cumulates over the rows as each row is sequentially read out. The back-projection coordinates are correspondingly corrected based upon the above described delay.

Abstract: A radiographic imaging method and system use a radiation solid state detector or a flat panel detector (FPD). The method and system enable radiographic imaging to be continued for a while after occurrence of pixel defects that may lower image quality and minimizing adverse effects of the pixel defects. The pixel defects are analyzed in the respective local regions on the detector. A pixel defect correction is not made on local regions where the pixel defect exceeds a given tolerance but these regions are marked on the radiographic image for recognition.

Abstract: A PET apparatus comprises a plurality of detector units in the circumferential direction, wherein the detector unit includes a plurality of unit substrates therein, and wherein the unit substrate includes: a plurality of detectors upon which a ?-ray is incident; and an analog ASIC and digital ASIC for processing a ?-ray detection signal outputted by each of the detectors. The analog ASIC includes two slow systems having mutually different time constants, each of which outputs a pulseheight value. A noise determination part of the digital ASIC determines whether a relevant detection signal is an intended ?-ray detection signal or a noise based on a correlation between the pulseheight values, and a noise counting part counts the number of times of noise determination, and a detector output signal processing control part controls the signal processing with respect to an output signal from a relevant detector based on the count.

Abstract: A nuclear medical diagnosis apparatus capable of attaining improvement of the sensitivity by the reduction of a count loss of the data is provided. A data sort section inside a data acquisition unit re-arranges and outputs the data packet from a plurality of auxiliary data acquisition unit in order of the detection time data. A coincidence detection section includes a pair check section and a pair generation section. The pair check section refers to a context on the data packet re-arranged in order of the detection time, and judges a pair relating to a coincidence counting. The pair generation section, based on this judgment result, merges the data packet used as a pair, and outputs the same to the collection work station.

Abstract: A method and/or device of adaptively controlling an exposure duration for a camera. A determination is made as to whether motion is present. If it is determined that motion is present, exposure duration for one or more images is automatically decreased. If it is determined that motion is not present, the frame exposure duration is automatically increased.

Abstract: The present invention provides a nuclear medicine imaging apparatus and image data generation method that achieves restarting of the generation of projection data and at an early stage while monitoring a variation of count values for detecting an occurrence of non-permissible body movement of a patient. The image processing apparatus consistent with the present invention detects a pair of gamma-rays successively emitted from an object with a radioactive isotope through a pair of detector modules in a data detecting unit. A data processing unit and an incident direction calculating unit in the image processing apparatus respectively calculate a gamma-ray detection position and a gamma-ray incident direction based on the acquired detection signals. A projection data generating unit in the apparatus generates monitoring projection data based on each count value of the detection signals in correspondence to the gamma-ray detection position and the gamma-ray incident direction.

Abstract: A method and apparatus for correcting the output of sensors of a radiation detector by tracking a baseline value detected by the detector during quiescent operation, calculating an average to reduce noise, and storing the average as an offset value for correcting forthcoming data to eliminate the offset.

Abstract: A nuclear medial diagnosis apparatus is used for performing diagnosis by administering a medicine marked with a radioactive isotope into an examinee and by using an image obtained by detecting gamma rays emitted from a particular organ or tumor where the medicine is accumulated. An image (an image created by an image creation unit) is created by a signal (a signal as an output from a radiation detector) corresponding to the energy of the gamma ray detected by a radiation detector. The image includes a contamination component attributed to gamma scattering in the radiation detector. An image correction operation unit performs a convolution operation to obtain a contamination image. The contamination image is subtracted by a corrected image creation unit. Thus, it is possible to prevent image degradation by the gamma ray scattering in the radiation detector.

Abstract: In a method for correction of an image in a series of images acquired with an x-ray detector; wherein the x-ray detector is composed of a number of detector elements and an acquired image is composed of image elements associated with the detector elements, a series of detector signals is generated in a detector element by x-ray radiation, the detector signals respectively exhibiting a detector-specific temporal decay curve; and an image element to be corrected and acquired over a predetermined acquisition interval contains signal portions of the current and preceding detector signals acquired during this acquisition interval. By calculating signal portions of preceding detector signals acquired in the acquisition interval and subtracting them from the image element to be corrected, the image quality of an image from a series of images acquired with a digital image acquisition apparatus is improved.

Abstract: An image from a gamma camera, e.g., from a radiopharmaceutical, is corrected for scatter. The image is approximated by estimating the center of the organ and supposing a Guassian response that is scatter-corrected.

Abstract: Detector efficiency data is generated for a positron emission tomography scanner (2) including a single photon source by conducting a blank scan acquisition procedure using the single photon source. The acquired detection count data is processed using an efficiency estimation algorithm to calculate data efficiencies of individual detectors in the detector array (8). In one embodiment, the detection count data is output as artificial coincidence count data and the efficiency estimation algorithm operates on the artificial coincidence count data. The method can be used in a non-rotating scanner or a rotating scanner.

Abstract: A method for correcting a positron emission tomography (PET) emission image is described. The method includes obtaining a PET emission sinogram of an object, obtaining a computed tomography (CT) image for a scanned portion of the object, the object having a truncated portion outside a field of view (FOV) of a CT image, determining a correction set of CT data based on a measured set of CT data within the CT sinogram, generating modified attenuation correction factors from the measured and correction sets of CT data, and correcting the PET sinogram using the modified attenuation correction factors.