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Kinetic Parameter Imaging with Dynamic PET

Kinetic parameter estimation with Dynamic Positron Emission Tomography (PET) has a wide range of applications ranging from tumor studies to drug delivery. Estimation of the parameters require that the blood input function is known. Clasically, this is performed with arterial sampling which poses helath risks, require extra time and personnel, and also very difficult for especially small animal experiments.

We develop methods that eliminate the need of known blood function. The blood function is estimated simultaneously based on the sinogram directly for a better accuracy as opposed to the reconstructed images.



The blood input function is accurately estimated with the proposed method
(solid: arterial sampling, dashed: estimated).
This eliminates the need for arterial sampling with dynamic PET studies.

  • We have also developed methods based on the method of moments (MOM) to tackle the problem of local minima with dynamic PET. Our MOM algorithm can be used both as an approximate estimate or to initialize the iterative algorithms to avoid local minima.



    We observe that MSE does not change significantly and the problem of non-convergent results is successfully removed.
    The 28 datasets are collected from mice as part of a drug delivery study.
    MOM: method of moments, CGM: conjugate gradient method, CGM MOM: CGM initialized with MOM,
    RFIT: RFIT developed at Lawrence Berkeley Lab, RFIT MOM: RFIT initialized with MOM.

  • References:
    1. Y. Cheng, I. S. Yetik, "Propagation of blood function error to the final kinetic parameter estimates with dynamic PET", submitted.
    2. M. Gadiya, I. S. Yetik, "Direct reconstruction of kinetic parameter images with ordered subsets", Proceedings of Medical Imaging Conference, 2008.
    3. F. Pektas, I. S. Yetik, "Covariance expressions for implicit estimators of kinetic parameters with dynamic PET ", Proceedings of IEEE Electro/Information Technology , pp. 316-320,2008.
    4. Y. Cheng, I. S. Yetik, "Effect of the blood function error on the estimated kinetic parameters with dynamic PET", Proceedings of IEEE International Symposium on Biomedical Imaging, pp. 1585-1588, 2008.
    5. I. S. Yetik, J. Qi, "Direct estimation of kinetic parameters from the sinogram with an unknown blood function", Proceedings of IEEE International Symposium on Biomedical Imaging, pp. 295-298, 2006.
    6. I. S. Yetik, J. Qi, "A fast method for kinetic parameter estimation" Proceedings of IEEE Nuclear Science Symposium , pp. 3213-3216, 2006.