Abstract #3427
            PET attenuation correction for PET/MR by combining MR segmentation and selective-update joint estimation
                      Lishui Cheng                     1                    , Sangtae Ahn                     1                    , 						Dattesh Shanbhag                     2                    , Florian Wiesinger                     3                    , 						Sandeep Kaushik                     2                    , and Ravindra Manjeshwar                     1          
            
            1
           
           GE Global Research, Niskayuna, NY, United 
						States,
           
            2
           
           GE 
						Global Research, Bangalore, India,
           
            3
           
           GE 
						Global Research, Munich, Germany
          
            
          Attenuation correction is critical to accurate PET 
						quantitation. In PET/MR, MR-based attenuation correction 
						(MR-AC) has challenges in bone, air, lung and implant 
						regions. To address the problem, we combined 1) a 
						segmentation-based MR-AC method, which works well in 
						soft-tissue regions, and 2) a selective-update joint 
						estimation approach, which reconstructs both attenuation 
						and activity from PET emission data, to resolve the 
						attenuation in the challenging regions. The method was 
						evaluated on clinical data from a PET/MR scanner with 
						TOF information and it was demonstrated that the method 
						can distinguish between abdominal air and spinal 
						implant/bone regions, otherwise hidden in MR.
         
				
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