Disclosed herein is a method comprising: generating multiple radiation beams respectively from multiple locations toward an object and an image sensor, wherein the image sensor comprises an array of multiple active areas, and gaps among the multiple active areas, and capturing multiple partial images of the object with the image sensor using respectively radiations of the multiple radiation beams that have passed through and interacted with the object, wherein each point of the object is captured in at least one partial image of the multiple partial images.

Systems and methods for determining beam asymmetry in a radiation treatment system using electronic portal imaging devices (EPIDs) without implementation of elaborate and complex EPID calibration procedures. The beam asymmetry is determined based on radiation scattered from different points in the radiation beam and measured with the same region of interest ROI of the EPID.

A system for directional detection of radiation, comprises a plurality of scintillating crystals, responsive to the radiation and being arranged three-dimensionally, with voids between adjacent crystals, such that there are crystals that are inner and crystals that are outer within the arrangement. The system also comprises a plurality of light sensors coupled to the crystals for receiving optical signals from the crystals and responsively generating electrical signals, and a data processor receiving an electrical signal separately from each light sensor and calculating a direction of the radiation based on relative intensities of the signals and mutual occultation among different crystals.

An imaging system is provided. A method for installing the imaging system is provided. The imaging system may include a first modality imaging apparatus. The first modality imaging apparatus may have a detector including a scintillator unit, a photodetector unit, a circuit unit, a supporting block, and a supporting board. The supporting block may be disposed on an end of the scintillator unit. The supporting board may be disposed between the photodetector unit and the circuit unit.

A method and apparatus are provided for nonlinear energy correction of a gamma-ray detector using a calibration spectrum acquired from the background radiation of lutetium isotope 176 (Lu-176) present in scintillators in the gamma-ray detector. Further, by periodically acquiring Lu-176 spectra using the background radiation from the scintillators, the nonlinear energy correction can be monitored to detect when changes in the gamma-ray detector cause the detector to go out of calibration, and then use a newly acquired Lu-176 spectrum to update the calibration of the nonlinear energy correction as needed. The detector calibration is performed by comparing a reference histogram to a calibration histogram generated using the nonlinear energy correction, and adjusting the parameters of the nonlinear energy correction until the two histograms match. Alternatively, the detector calibration is performed by comparing reference and calibration values for specific spectral features, rather than for the whole Lu-176 spectrum.

A radiotherapy dose rate monitor system includes an electrode configured to be impinged by radiotherapy radiation, and a current measurement circuit configured to measure a current through the electrode. An emission of secondary electrons emitted from the electrode provides a majority of current through the electrode.

The application provides a three-dimensionally heterogeneous PET system comprising at least two heterogeneous detector modules, each comprising at least two kinds of crystal strips closely arranged to form different detection performances levels for different kinds of crystal strips and same detection performances levels for same kind of crystal strips. Parameters of detection performances of crystal strips comprise energy resolution, density, size and light output, wherein different detection performances levels for crystal strips comprise one or more of parameters of detection performances of crystal strips being in different levels. Compared with a high spatial resolution PET system, the application effectively reduces manufacturing costs of a PET system without significantly reducing spatial resolution thereof. Compared with an ordinary spatial resolution PET system, it improves spatial resolution of a PET system by slightly increasing its cost, and can also provide imaging field of view with high spatial resolution in radial direction.

The invention relates to a system and a method for determining a characteristic of a blood vessel portion, which comprises blood including a contrast agent exhibiting resonant absorption of x-ray photons at a specific energy. The system comprises a tunable monochromatic x-ray source (21) emitting x-ray radiation, an x-ray detector device (22) for detecting the x-ray radiation after it has travelled through the blood vessel portion. A control unit (26) varies a tuning of the x-ray source (21) to vary the energy of the x-ray radiation emitted by the x-ray source (21), and an evaluation unit (27) determines a tuning of the x-ray source (21) at which nuclear resonant absorption of the x-ray radiation incident onto the blood vessel portion occurs and estimates the characteristic on the basis of the determined tuning. The characteristic may particularly be the blood velocity in the blood vessel portion.

The present invention provides a method of calibrating gamma-ray and photon counting detectors, including, but not limited to, monolithic crystal detectors. The method of the present invention is based on the observation that measurement of fan beam datasets allows the synthesis of collimated beam data to derive MDRFs by use of an algorithm that finds the common or intersecting data subsets of two or more orthogonal calibration datasets. This makes the calibration process very efficient while still allowing the full benefits of maximum-likelihood event-parameter estimation that incorporates the statistical nature of the light sensor measurements.

A positron emission tomography (PET) technique that can enhance the image resolution and system sensitivity of a clinical PET/CT scanner for imaging a whole body or a target region of a subject is provided. The system includes a detector array and a detector panel. The detector array includes an array of gamma ray detectors defining a field of view of a scanner and configured to detect at least one coincidence event. The detector panel includes an array of gamma ray detectors having a higher intrinsic spatial resolution than the detector array and positioned in closer proximity to a patient table than the detector array. The detector panel is positioned outside the field of view defined by the detector array during at least a portion of scanning by the PET system. The detector panel is configured to detect at least one coincidence event in cooperation with the detector array. The control unit is configured to control the detector array, the detector panel, and the patient bed to operate in cooperation with each other.