Radiation protection to patients in radiology: A review study

The present paper aims at reviewing different shielding methods used for patients in medical imaging and investigating their merits and demerits. These techniques are generally classified into two groups including in-plane and out-of-plane shielding. Bismuth (Bi) shielding is a conventional in-plane shielding method used during CT examinations to protect radiosensitive organs. This method has reduced radiosensitive organs dose by about 34-68% during different CT examinations. However, it causes considerable degrading effects on image quality and for this reason AAPM recommended against its application in 2017. Recently, another in-plane shielding, named Saba shielding, introduced wherein all the shortcomings and deficits of Bi shielding have been resolved or fixed. Saba shielding reduces radiosensitive organs dose by about 50% without degrading image quality. Out-of-plane shields can decrease the patient dose by more than 55%. However, due to the low dose of the scattered radiation received by out-of-plane organs, in the case of applying out-of-plane shields such as gonad or thyroid shields, the risk and benefit of their usage should be evaluated.