Shielding Trends

•         Additional shielding was needed in Hot Lab  
  

•         Shielded syringes  
  

•         Some institutions added small amounts of shielding in walls

We all became fairly comfortable

New Shielding Issues ...Changes Occurred

•         PET had been limited primarily to only institutions with cyclotrons on site  
  

•         Technology improved  
  

•         PET became more common

 Shielding changes were needed to accommodate PET scanning

• Positron Emission Tomography

•         PET uses annihilation radiation, produced when a positron collides with a negatron (electron), for Nuclear Medicine imaging

•         This collision always produces two 0.511 MeV photons
  

Shielding 0.511 MeV Photons

•         Photons with energy this high are difficult to shield  
  

•        Higher penetrating ability  
  

•        Increased radiation (Compton) scatter

        Radiation sources

•         Doses  
  

•         Patients