Estimates of dose to the bladder during direct radionuclide cystography: concise communication.

We estimate the absorbed dose to the bladder walls, Db, due to [99mTc]pertechnetate direct radionuclide cystography, with due consideration to the dynamic nature of the examination. Our analytical method resulted in Db values expressed as functions of the bladder filling time. These values are compared with published data based on a static bladder model. It is shown that the Db value depends strongly on the protocol under which the examination is carried out. It is also shown that the normal saline flow rate and the time of the administration of the radioactive material can be adjusted so that the radiation burden may be greatly reduced.