Correction information acquisition method for performing attenuation correction on PET image of breath or heart

Abstract

The invention discloses a correction information acquisition method for performing attenuation correction on a PET image of a breath or a heart. The method comprises the following steps: acquiring PETdetection data with flight time information and a gating signal reflecting periodic movement of the breath or the heart in the data; obtaining combined data of each phase in the B phases in one period; obtaining the sum of the combined data of each phase, obtaining a conversion matrix for conversion of the combined data of any two phases in the B phases, and establishing a first relational expression of the sum of the conversion matrixes and a second relational expression of the sum of the conversion matrixes; establishing an objective function of a PET radioactivity distribution estimation value including a basic phase and a linear attenuation coefficient image; and performing iterative optimization on the target function to obtain estimated values of x0 and mu0, which meet the requirements of maximizing the target function. In the PET image reconstruction, all PET data instead of data of a certain phase are used, so that the signal-to-noise ratio of the reconstructed image is improved.

Description

technical field [0001] The invention relates to the field of medical imaging, in particular to a correction information acquisition method and system that can be used in a positron emission computed tomography system to perform attenuation correction on PET images of respiration or heart. Background technique [0002] Positron Emission Tomography PET (Positron Emission Tomography) 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 nuclides into the human body, and then perform functional metabolic imaging on the patient through the PET system to reflect the situation of life metabolic activities. PET scans are usually accompanied by other modality scans (such as CT, MRI, etc.) to obtain imaging of the patient's anatomical structure. Obtain the tissue density distribution of the patient, calculate the attenuation properties (attenuation coefficient) of the tissue on th...

AI Technical Summary

Problems solved by technology

[0006] 1. After PET data acquisition, each phase is reconstructed separately, so the data available in the reconstruction process is much less than that of static scanning, which leads to a very low signal-to-noise ratio of the final gated image

In this way, even if the blurring effect of object motion on the lesion is removed, the added noise will greatly reduce the detectability of small lesions

[0007] 2. Since other modality images correspond to a certain phase position, at most one phase of the PET multi-phase image obtained by the gating method can match the anatomical structure image, which will still cause the PET image to be matched with other modality images. Quasi-fusion produces deviations (especially near the diaphragm with the largest movement range), and using instantaneous multi-modal images to perform attenuation correction on the average PET image will inevitably cause errors, which will produce local artifacts on the PET image and affect quantitative analysis. , may affect the accurate diagnosis and treatment plan formulation of thoracic and abdominal tumors

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] 4. When PET is combined with other phantoms, sometimes satisfactory attenuation correction images cannot be obtained, such as PET / MR imaging

On the one hand, this increases the workload of doctors. On the other hand, only one frame of images appears in the diagnostic report, and other reconstruction results are not used. This has a lot of information redundancy, wasting data and computing time

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