TECHNIQUE FOR JOINT ESTIMATION OF ACTIVITY, ATTENUATION AND SCATTER IN EMISSION TOMOGRAPHY
Publication Date: 2015-Jul-29
The IP.com Prior Art Database
This disclosure proposes a technique for joint estimation of activity, attenuation and scatter for accurate quantitation in an emission tomography. The technique updates scatter estimates iteratively in the context of joint estimation where prior information on attenuation from MR images is used. The technique refines attenuation and scatters estimates and thereby improves quantitation accuracy.
The present invention relates generally to emission tomography, and more particularly to a technique for joint estimation of activity, attenuation and scatter for accurate quantitation in emission tomography.
Medical imaging utilizes radiations to acquire images that show the function and anatomy of various organs, bones or tissues of a body. In emission tomography, such as positron emission tomography (PET) and single-photon emission computerized tomography (SPECT), attenuation correction is required for accurate quantitation of activity. When information related to attenuation is unavailable or incomplete, the activity and attenuation can be jointly estimated using emission data (and some prior information about attenuation). The joint estimation approach is useful in PET/magnetic resonance (MR), where MR provides imperfect information about attenuation in challenging regions, such as implants, bones and internal air cavities. Further, scatter correction is also critical for the accurate quantitation of the activity.
In conventional techniques, incomplete attenuation information and inaccurate attenuation correction cause errors in activity quantitation. Further, imperfect attenuation information also causes errors in scatter estimation and results in quantitation errors. Furthermore, conventional techniques extract the accurate attenuation in some regions such as implants, bones, air, among others from MR images with limited success. As a result, the conventional techniques are unable to refine attenuation and scatter estimates and thereby are unable to improve quantitation accuracy.
It would be desirable to have a technique for joint estimation of activity, attenuation and scatter for the accurate quantitation in emission tomography.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 is a flow chart of a method for jointly estimating activity, attenuation and scatter for accurate quantitation in emission tomography.
The disclosure proposes a technique or method for joint estimation of activity, attenuation and scatter for accurate quantitation in emission tomography.
Figure 1 is a flow chart of a method for jointly estimating the activity, attenuation and scatter for accurate quantitation in emission tomography according to the technique described herein.
As illustrated in Figure 1, the method starts at step 102. The method proceeds to step 104 at which the method obtains an emission data, a correction data and/or anatomical images. The emission data may be non-time-of-flight positron emission tomography (non-TOF PET) data, time-of-flight positron emission tomography (TOF PET) data or Single-photon emission computed tomography (SPECT) data. The correction data may include normalization and/or estimated random coincidence sinograms. The anatomical images may be magnetic resonance (MR) or computed ...