Model based estimation of a complete or partial positron emission tomography attenuation map using maximum likelihood expectation maximization

1. A method of correcting attenuation in a magnetic resonance (MR) scanner and a positron emission tomography (PET) unit, the method comprising:

acquiring PET sinogram data of an object within a field of view of the PET unit; and

producing an attenuation map based on a maximum likelihood expectation maximization (MLEM) of a parameterized model instance and the PET sinogram data.

2. The method of claim 1 , further comprising:

acquiring MR data of an object within a field of view of the MR scanner; and

producing a first attenuation map based on the acquired MR data.

3. The method of claim 2 , wherein the producing the attenuation map includes producing the first attenuation map and a second attenuation map.

4. The method of claim 3 , wherein the second attenuation map provides maximum likelihood of the PET sinogram data within a field of view of the PET unit including all parts not within the field of view of the MR scanner.

5. The method of claim 1 , wherein the producing the attenuation map includes,

generating a model,

parameterizing the model by model parameters, and

creating the parameterized model instance based on the acquired PET sinogram data and the parameterized model.

6. The method of claim 5 , wherein the model is a statistical model.

7. The method of claim 6 , wherein the parameterizing the statistical model includes parameterizing the statistical model by deformation parameters, attenuation parameters and affine parameters.

8. The method of claim 6 , wherein the generating the statistical model includes performing principal component analysis of deformation fields and attenuation maps resulting from coregistrations of example data sets.

9. The method of claim 1 , wherein the producing the attenuation map includes,

generating a model, and

adapting the model to an initial attenuation map, the parameterized model instance being created based on the adapted model.

10. The method of claim 1 , wherein the PET unit is configured to acquire the PET sinogram data.

11. The method of claim 1 , wherein a computer connected to the MR scanner and the PET unit is configured to produce the attenuation map.

12. A non-transitory computer-readable medium, when run on a computer, configured to instruct the computer to perform the method of claim 1 .

13. A method of correcting attenuation in a magnetic resonance (MR) scanner and a positron emission tomography (PET) unit, the method comprising:

acquiring PET sinogram data of an object within a field of view of the PET unit;

acquiring MR data of the object within a field of view of the MR scanner;

producing an attenuation map based on a maximum likelihood expectation maximization (MLEM) of a parameterized model instance and the acquired PET sinogram and MR data, the MLEM being constrained by model parameters of the parameterized model instance.

14. The method of claim 13 , wherein the producing the attenuation map includes producing a PET attenuation map.

15. The method of claim 14 , wherein the producing the PET attenuation map includes,

generating a model,

parameterizing the model by the model parameters, and

creating the parameterized model instance based on the parameterized model.

16. The method of claim 15 , wherein the model is a statistical model.

17. The method of claim 16 , wherein the model parameters are the deformation parameters and the attenuation appearance parameters.

18. The method of claim 17 , wherein the model parameters further include affine parameters.

19. The method of claim 14 , further comprising:

producing an MR attenuation map.

20. The method of claim 13 , wherein the producing the attenuation map includes,

generating a model, and

adapting the model to an initial attenuation map, the parameterized model instance being created based on the adapted model.

21. The method of claim 13 , wherein the PET unit is configured to acquire the PET sinogram data.

22. The method of claim 13 , wherein a computer connected to the MR scanner and the PET unit is configured to produce the attenuation map.

23. The method of claim 13 , wherein the MR scanner is configured to acquire the MR data.

24. A non-transitory computer-readable medium, when run on a computer, configured to instruct the computer to perform the method of claim 13 .

25. A device comprising:

a positron emission tomography (PET) unit including a plurality of detection units and configured to acquire PET sinogram data of an object within a field of view of the PET unit;

a magnetic resonance (MR) scanner configured to acquire MR data of the object within a field of view of the MR scanner; and

a computer configured to produce an attenuation map based on a maximum likelihood expectation maximization (MLEM) of a parameterized model instance and the acquired PET sinogram and MR data, the MLEM being constrained by model parameters of the parameterized model instance.