An analytical and Monte Carlo investigation of the sufficiency of the present shielding of PET/CT imaging system at Tehran's Shariati hospital‎

Abstract

‎By the rapid development of imaging systems such as PET/CT for diagnosis of cancer‎, ‎the protection of staff and public has become a main health concern‎. ‎Due to serious and irreversible harms of ionization radiations‎, ‎protection of all those who are exposed is the main concern of health issues‎. ‎The main basis of the calculation of the shielding design in the medical imaging systems is that the absorbed dose should not exceed the allowed limit‎. ‎In this study‎, ‎the current shielding status of the PET/CT installations in Tehran's Shariati hospital was investigated using the MCNPX Monte Carlo code to ensure that the dose limits for both the controlled and uncontrolled area are not violated‎. ‎The proposed simulation method was benchmarked with a validated analytical method‎. ‎Shariati hospital provides services to four patients every day‎, ‎leading to a dose rate in the range of 2.6 × 10^-6 to 9.35 × 10^-3 mSv/week‎. ‎The minimum dose rate in this range represents the value behind the door of the waiting room (public uncontrolled area)‎, ‎while the maximum in this range corresponds to the value behind the glass of the scanner room (operator controlled area)‎. ‎The simulation results for 8 patients/day in this center showed that the dose rate behind the wall of the injection room will increase from 4.88 ×10^-6 mSv/week to 2.81 × 10^-2 mSv/week‎, ‎which is well below the recommended levels‎. ‎This indicates that the present shielding is adequate for up to four more patients per day‎.