<prompt> Positron emission tomography imaging is commonly performed using: September 2011Barium sulphate2-18 fluoro-2-deoxy D-glucose 18 FDGMyodilOxygen 15  <response>: Ans. B: 2-18 fluoro-2-deoxy D-glucose 18 FDG The majority of clinical PET imaging is now performed with the glucose analogue 2-18 fluoro-2-deoxy D-glucose 18 FDG which has a half life of 110 min. PET scan: Differentiates radiation necrosis from active neoplasm following therapy Recent role is in investigation of recurrent GIST tumours 