Correction information acquisition method for performing attenuation correction on PET activity distribution image

Abstract

The invention discloses a correction information acquisition method for performing attenuation correction on a PET activity distribution image. The method comprises the following steps: S0, acquiringPET detection data with flight time information when a PET system scans; S1, based on the fact that PET detection data obeys Poisson distribution, perforeming modeling processing on the PET detectiondata, and obtaining a logarithmic likelihood function L (x, y); S2, priori knowledge constraint based on a linear attenuation coefficient, initializing linear attenuation coefficient distribution to generate an initial value [mu]0, adjusting L (x, y), generating an objective function S3 with a priori knowledge constraint condition, and optimizing the objective function by adopting an iterative algorithm according to the initial value [mu]0 to obtain an estimated value of unknown x and [mu] meeting the maximization of the objective function. In specific implementation, the final estimated valuex and [mu] are applied to PET image reconstruction, so that the problem of attenuation artifacts in PET image reconstruction in the prior art can be solved, and accurate quantification of attenuationcorrection can be ensured.

Description

technical field [0001] The invention relates to the field of medical imaging, in particular to a correction information acquisition method for performing attenuation correction on a PET activity distribution image, a PET activity distribution image reconstruction method and a PET system. Background technique [0002] Positron Emission Tomography (PET) is a high-end nuclear medicine imaging diagnostic equipment. In practice the use of radionuclides (eg 18 F. 11 C, etc.) Label the metabolites and inject the metabolites labeled with nuclides into the human body, and then perform functional metabolic imaging on the patient through the PET system to reflect the metabolic activities of life, so as to achieve the purpose of diagnosis. [0003] When the PET system collects, the photons will attenuate in the human body before reaching the PET system. Compared with the coincidence events inside the object, the coincidence events on the surface of the object have a greater detection ...

AI Technical Summary

Problems solved by technology

When scanning heavy patients, imaging with other modalities will likely not provide a large enough scan field, resulting in truncated attenuation images

This incomplete attenuation information can also produce attenuation artifacts in PET reconstructions

[0009] Finally, satisfactory attenuation-corrected images are sometimes not obtained when PET is co-imaged with other phantoms, such as PET / MR imaging

In contrast to CT imaging, MR primarily utilizes magnetic spin imaging rather than tissue density distribution imaging and therefore does not directly provide accurate information on the nature of tissue attenuation

At present, the algorithm of attenuation correction based on MR imaging is complicated and the accuracy is not high, which easily leads to the generation of attenuation artifacts

In addition, the scanning bed and MR coil cannot be displayed on the MR image, which will also affect the subsequent attenuation correction

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