Patent ID: 11961164
Assignee: SIEMENS MEDICAL SOLUTIONS USA, INC.
Field: Medical technology (Instruments)
Classification: CPC G  A | IPC A  G

Claim 5:
6. A positron emission tomography (PET) calibration system comprising:
a PET scanner having an axially short phantom mounted on a patient bed that moves in an axial motion through the PET scanner during the CBM acquisition; and
a scintillation crystal efficiency calibration system that performs a method comprising:, (a) generating time-of-flight (TOF) data of positron annihilation activity in the axially short phantom during the CBM acquisition, while accounting for the axial motion of the patient bed during the CBM acquisition, as a first data set that comprises CBM data y with spatial projection index j=(ρ,θ,ζ), wherein ρ is transaxial radial coordinate, θ is azimuthal coordinate, and TOF bin index T is modeled by combining true events modeled projection p from emission object f, defined by voxel index k, corrected for scanner efficiency through a normalization array n for attenuation by α, and scatter estimation S, corrected for scanner efficiency, and mean random data r according to:, y
     _
    
    
     ρθ
     ⁢
     ζ
     ⁢
     T
    
   
   =
   
    
     
      
       a
       
        ρ
        ⁢
        θ
        ⁢
        ζ
       
      
      ⁢
      
       
        n
        ρθζ
        
         -
         1
        
       
       (
       ε
       )
      
      ⁢
      
       
        ∑
        k
       
       
        
         C
         
          
           ρθζ
           ⁢
           T
          
          ,
          k
         
        
        ⁢
        
         f
         k
        
       
      
     
     +
     
      
       n
       ρθζ
       
        -
        1
       
      
      ⁢
      
       S
       
        ρθζ
        ⁢
        T
       
      
     
     +
     
      
       r
       _
      
      
       ρθ
       ⁢
       ζ
       ⁢
       T
      
     
    
    =
    
     
      
       a
       
        ρ
        ⁢
        θ
        ⁢
        ζ
       
      
      ⁢
      
       
        n
        ρθζ
        
         -
         1
        
       
       (
       ε
       )
      
      ⁢
      
       
        p
        _
       
       
        ρθζ
        ⁢
        T
       
      
     
     +
     
      
       n
       ρθζ
       
        -
        1
       
      
      ⁢
      
       S
       
        ρθζ
        ⁢
        T
       
      
     
     +
     
      
       r
       _
      
      
       ρθζ
       ⁢
       T
      
     
    
   
  
  ;
 

wherein C is the geometrical projection system matrix;
wherein ε is the crystal efficiency; and
wherein coordinate ζ is the CBM data normalization;, (b) generating a complementary data set by integrating the TOF data over the axial motion of the patient bed during the CBM acquisition, wherein the complementary data set is modeled by the equation:, y
     _
    
    
     ρθ
     ⁢
     zT
    
   
   =
   
    
     
      
       
        n
        
         ρθ
         ⁢
         z
        
        
         -
         1
        
       
       (
       ε
       )
      
      ⁢
      
       B
       (
       
        
         a
         ρθζ
        
        ⁢
        
         
          ∑
          k
         
         
          
           C
           
            
             ρθζ
             ⁢
             T
            
            ,
            k
           
          
          ⁢
          
           f
           k
          
         
        
       
       )
      
     
     +
     
      
       
        n
        
         ρθ
         ⁢
         z
        
        
         -
         1
        
       
       (
       ε
       )
      
      ⁢
      
       B
       ⁡
       (
       
        S
        
         ρθζ
         ⁢
         T
        
       
       )
      
     
     +
     
      
       r
       _
      
      
       ρθ
       ⁢
       zT
      
     
    
    =
    
     
      
       
        n
        
         ρθ
         ⁢
         z
        
        
         -
         1
        
       
       (
       ε
       )
      
      ⁢
      
       
        p
        _
       
       
        
         ρθ
         ⁢
         zT
        
        +
       
      
      ⁢
      
       
        n
        
         ρθ
         ⁢
         z
        
        
         -
         1
        
       
       (
       ε
       )
      
      ⁢
      
       S
       
        ρθ
        ⁢
        zT
       
      
     
     +
     
      
       r
       _
      
      
       ρθ
       ⁢
       zT
      
     
    
   
  
  ,
 

wherein z is axial plane coordinate, B is a blurring operator defined as, B
   ⁡
   (
   
    
     p
     _
    
    
     ρθζ
     ⁢
     T
    
   
   )
  
  =
  
   
    ∫
    
      
     0
    
    
      
     
      t
      
       a
       ⁢
       c
       ⁢
       q
      
      ′
     
    
   
   
    
     dt
     ′
    
    ⁢
    
     
      ∑
      ζ
     
     
      
       e
       
        
         -
         λ
        
        ⁢
        t
       
      
      ⁢
      
       
        d
        
         ρθ
         ⁢
         z
        
       
       (
       t
       )
      
      ⁢
      
       
        p
        _
       
       
        ρθζ
        ⁢
        T
       
      
      ⁢
      
       
        δ
        
         z
         ,
         
          Z
          ⁡
          (
          
           ζ
           ,
           t
          
          )
         
        
       
       ., and Y ρθz, a motion blurring operator, is calculated by:, y
    
     ρθ
     ⁢
     z
    
   
   =
   
    
     B
     ⁡
     (
     
      y
      
       ρ
       ⁢
       θ
       ⁢
       ζ
      
     
     )
    
    =
    
     
      ∫
      
        
       0
      
      
        
       
        t
        
         a
         ⁢
         c
         ⁢
         q
        
        ′
       
      
     
     
      
       dt
       ′
      
      ⁢
      
       
        ∑
        ζ
       
       
        
         e
         
          
           -
           λ
          
          ⁢
          t
         
        
        ⁢
        
         
          d
          
           ρθ
           ⁢
           z
          
         
         (
         t
         )
        
        ⁢
        
         y
         ρθζ
        
        ⁢
        
         δ
         
          z
          ,
          
           Z
           ⁡
           (
           
            ζ
            ,
            t
           
           )
          
         
        
       
      
     
    
   
  
  ,, wherein t′acq is CBM acquisition time; and, (c) simultaneously reconstructing the positron annihilation activity and crystal efficiency normalization coefficient from the complementary data set.