X-ray computed tomography apparatus and photon counting method

Abstract

The X-ray computed tomography apparatus (1) according to this embodiment includes: an X-ray generation unit that generates X-rays; an X-ray detection unit (103) that has a scintillator and a light detection element (104); a peak detection unit (120) , according to the output signal from the photodetection element (104), detect a plurality of peaks corresponding to a plurality of X-ray photons incident to the scintillator; the characteristic determination part (124), according to the time and the time when each of the plurality of peaks are detected A plurality of peaks, determining the attenuation characteristics of the scintillation light based on each of the plurality of X-ray photons and the output reduction characteristics of the photodetection element; the peak correction unit (126) corrects the detected multiple The peak value; the counter (130) counts the number of X-ray photons respectively corresponding to the multiple corrected peak values; the reconstruction unit (16) reconstructs the medical image according to the output from the counter (130).

Description

technical field [0001] Embodiments of the present invention relate to an X-ray computed tomography apparatus having a counter and a photon counting method. Background technique [0002] There is an X-ray computed tomography apparatus (Computed Tomography: hereinafter referred to as a photon counting X-ray CT apparatus) that reconstructs an image of a subject from the number of photons of X-rays output from an X-ray detector. In addition, a high count rate (ratio of the number of detected photons to the number of incident photons toward the X-ray detector) is required as performance of the X-ray detector of the photon counting X-ray CT apparatus. The so-called high count rate is, for example, every 1mm 2 for 10 6 about a count rate. For example, semiconductor detectors such as CZT (CdZnTe: cadmium zinc telluride) and CdTe (cadmium telluride) have been trial-produced as X-ray detectors. In order to obtain a high count rate of the semiconductor detector, efforts have been m...

AI Technical Summary

Problems solved by technology

However, during the luminescence time of the scintillator (typically 40×10 -9 s or so), due to the occurrence of incident events based on other X-ray photons, there is a problem of superposition of the output electrical signal

In addition, when the next X-ray photon is incident during charging of the photodetector, the output signal becomes weaker than that based on the incident of a single X-ray photon, and as a result, there is a problem that an appropriate energy integral value cannot be obtained

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