Effectiveness of shielding materials against 177Lu gamma rays and the corresponding distance relationship

The purpose of this study is to determine the dose reduction of different shielding materials at various distances from a 177Lu photon radiation source. Two protective aprons with lead equivalent thicknesses of 0.25 mm and 0.35 mm and tungsten-containing rubber (TCR) were used as shielding materials. A vial containing 177Lu was sealed in a lead container so that a narrow beam went out through a 3 mm-diameter hole. The dose rate was measured at distances of 0, 10, 50, 100, and 200 cm from the source using a NaI scintillation survey meter to obtain the rate of dose reduction. TCR was tested with thicknesses ranging from 0.3 to 1.0 mm at 0.1 mm intervals and from 1.0 to 4.0 mm at 0.5 mm intervals. At distances of 0, 10, 50, 100, and 200 cm, the dose reduction for the lead equivalent thickness of 0.25 mm were 32.7