Radiation design and control features of a hospital room for a low dose rate remote afterloading unit

We have renovated, and used for four years, a small 3.4 m x 4.3 m conventional patient second floor hospital room to accommodate a low dose rate remote afterloading unit containing 13 GBq (0.35 Ci) of 137Cs. Supplemental room shielding consists of a power assisted door (536 kg, 1.7 cm thickness of lead), 1.3 cm lead wall shielding at selected wall locations and on a projector shield beneath the bed, and 0.6 cm of lead over the floor above. Radiation control features consisted of a room interior radiation detector independent of the remote afterloading unit, a redundant patient/nurse communication system, a remote control system, a door interlock system to insert and retract the radioactive pellets, and a visible and audible status indicator system located at a nearby nurses' work station. Renovation costs (in 1990 dollars) were $383 per square foot; total project costs were $187,000. Nursing personnel radiation exposure was reduced from about 6 microSv (mg Ra eq)-1 (0.6 mrem (mg Ra eq)-1) to about 0.7 microSv (mg Ra eq)-1 (0.07 mrem (mg Ra eq)-1, almost a tenfold reduction.