Apparatus for calibrating photon-counting type of radiation detector and method of calibrating the same

摘要

There is provided a calibration apparatus used for a photon counting type of radiation detector. In this apparatus, a radiation condition of a radiation is set such that particles of the radiation (X-rays) which are incident on a plurality of detection modules are piled up over each other at a probability which is equal to or less than a predetermined value. Under the setting of this radiation condition, detection sensitivities for the radiation are made uniform among the plurality of detection modules. Using this uniformed result, the detection sensitivities for the radiation are further made uniform every channel of each of the pixels formed by circuit groups including the plurality of detection modules, discrimination circuits and data calculation circuits and every discrimination circuit in each channel.

主权项

1. A calibration apparatus used in a photon counting type of radiation detector, the radiation detector comprising:
a detector provided with a plurality of detection modules, each of the detection modules having a plurality of detection elements provided as a plurality of pixels, each of the detection elements detecting, as a photon, a radiation radiated from a radiation source and outputting an electric pulse signal whose quantity depends on energy of the photon; at least one discrimination circuit provided for discriminating amounts of the energy in an energy spectrum of the radiation, wherein at least one energy threshold for setting a plurality of energy ranges are provided to each of the pixels; a data production circuit producing counting data indicative of a number of particles of the radiation of every pixel and of every energy range, based on a count of the pulse signal outputted from each of the plurality of detection elements; and an image production unit producing an image of an object based on the counting data produced by the data production circuit, when the radiation is radiated to the object, the calibration apparatus comprising: a radiation condition setting unit setting a radiation condition of the radiation such that, when the particles of the radiations are incident on the plurality of detection modules, a probability of pileups of the incident particles is smaller than or equal to a predetermined value; a first calibrating unit calibrating the detection modules such that, in a state where the radiation condition is set for the radiation by the radiation condition setting unit, detection sensitivities for the radiation are uniformed among the plurality of detection modules or at the respective detection modules; and a second calibrating unit calibrating the modules, based on results calibrated by the first calibrating unit, such that the detection sensitivities for the radiation are uniform for every channel and every discrimination circuit in each channel is provided in a circuit group including, at least, the plurality of detection modules, the discrimination circuit, and the data production circuit.