<prompt> Radiation exposure is least inCT pelvisIVPCystographyMicturating cysto - Urethrogram  <response>: MCU : 1 - 2 msv - 60 chest x - ray.Cystography : 1- 8 msievert - 90cxr.IVP : 2 - 4 - 120cxr.CT pelvis : 10 - 500cxr. 