A Simultaneous Reconstruction Method of PET Concentration and Attenuation Coefficient

Abstract

The invention discloses a simultaneous reconstruction method for PET (Positron Emission Tomography) concentration and a damping coefficient. The method comprises the following steps of (1) acquiring coincidence counting; (2) constructing a PET state-space square; and (3) estimating the PET concentration distribution and damping coefficient distribution by using a UKF (Unscented Kalman Filtering) algorithm. According to the method, the damping coefficient and radioactive concentration are estimated simultaneously by using a robust unscented Kalman filter frame without a linear Jacobian matrix; meanwhile, the estimation of mean values and variances is kept by using a sampling method; and compared with the reconstruction method based on EKF (Extended Kalman Filtering), the method has the advantage of better processing system noise, measuring data noise and modeling errors.

Description

technical field [0001] The invention belongs to the technical field of PET imaging, and in particular relates to a simultaneous reconstruction method of PET concentration and attenuation coefficient. Background technique [0002] Positron emission tomography (PET) is a medical imaging technology based on nuclear physics and molecular biology. It can observe the metabolic activities of cells at the molecular level and provide an effective basis for early detection and prevention of diseases. When performing PET scanning, it is first necessary to inject drugs labeled with radioactive isotopes into the human body. Through the blood circulation system, these substances will form a certain distribution in various tissues and organs in the human body. Due to the short half-life of radioactive isotopes and their extreme instability, they will soon decay, and the positrons generated during the decay process will undergo an annihilation reaction with nearby free electrons, producing ...

AI Technical Summary

Problems solved by technology

At present, the attenuation correction of PET mostly adopts the method of transmission scanning or the scanning data of CT in PET / CT, but the scanning process using CT can easily introduce artifacts and affect the imaging quality. At present, the most accurate attenuation correction method is transmission scanning.

[0004] The biggest problem with transmission scanning is that it takes a long time, and the state of the patient may change, and it will increase the radiation exposure of the patient, so there have been some studies on the simultaneous estimation of attenuation coefficient and radioactive concentration, but they are more focused on SPECT (single photon emission computed tomography) studies using different attenuation methods

In the previous work, the system of using the state-space method Extended Kalman solution (EKF) to simultaneously estimate the attenuation coefficient and the distribution of radioactivity concentration has also been mentioned, but there are still several problems in this system, such as the Jacobian (Jacobian) matrix derivation, linearization of nonlinear problems, etc., which will cause errors in the estimation process

At the same time, due to the expansion of the dimension of the state vector, the addition of state variables and model parameters will also have a potential impact on the standard deviation of the solution results

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