Maximum radiation exposure is by

Examination Effective total dose (mSv) Chest radiograph 0.06 Skull radiograph 0.2 Pelvis radiograph 0.65 Lumbar spine radiograph 1.3 Upper GI series (Barium) 2.45 Abdomen radiograph 0.55 Barium enema 2.8 to 4 IVP/IVU 1.6 Extremities 0.01 Enteroclysis 1.5 CT chest 8 CT abdomen 10 CT head 3.5 RNI 4.8