PS-PMT (position sensitive-photomultiplier tube) based detector signal readout method and system

Abstract

The invention discloses a multianode PS-PMT (position sensitive-photomultiplier tube) based detector signal readout method and system. The signal readout method comprises the following steps of: converting M*N array signals output by a detector into M channels of signals and N channels of signals on orthogonal directions by a symmetry charge distribution circuit; respectively carrying out amplification forming and digital integration processing on the M channels of signals and the N channels of signals to generate the integral numerical values of the processed M channels and N channels; transferring the integral numerical values of the processed M channels and N channels to a computer side; and calculating the position of the center of gravity in each channel direction with a local center of gravity method so as to determine the action position of a gamma photon on the detector. According to the scheme of the invention, noise brought by invalid channels can be eliminated in a process of obtaining the position information of a gamma example, and the positioning precision of the detector (especially a big-array output detector) is improved.

Description

technical field [0001] The invention relates to the fields of nuclear detection technology and nuclear medical imaging technology, and in particular to a detector signal readout method and system based on a multi-anode position-sensitive photomultiplier tube. Background technique [0002] At present, nuclear detection technology based on scintillation crystal and photomultiplier tube (PMT) has been widely used in positron emission computed tomography (PET) and single photon emission computed tomography (Single PhotonEmission Computed Tomography, SPECT) represents the field of nuclear medicine imaging. [0003] As the initial link in the imaging process, the spatial resolution of the detector directly determines the spatial resolution index of the imaging system. The early detectors used an independent crystal and a single-channel PMT one-to-one coupling. This method is simple in principle, but Due to the large size of the PMT, the resolution is not high and the geometric ar...

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Problems solved by technology

Therefore, the larger the output array, the more noise it introduces, the worse the resolution of the detector, and the scalability of this scheme is poor for large-scale detectors

In addition, the distribution of the signals of each channel is to achieve different weight distribution by selecting different resistance values, and the resistance device has a certain accuracy error, which leads to relatively poor linearity in the detector plane image

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