Shielding efficiency of novel tungsten rubber against radionuclides of 99mTc, 131I, 18F and 68Ga

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

OBJECTIVE

The purpose of this study is to determine the dose reduction of different shielding materials at various distances from a 177Lu photon radiation source.

METHODS

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.

RESULTS

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%, 54.5%, 93.1%, 97.9%, and 99.6%, respectively; and for the lead equivalent thickness of 0.35 mm were 53.4%, 70.6%, 95.6%, 98.9%, and 99.6%, respectively. Without any shielding, the dose rate decreased by 34.4% at 10 cm and by 88.8% at 50 cm from the radiation source. The dose reduction for the TCR thickness of 3.5 mm was 89.8% at 0 cm and 93.3% at 10 cm. The TCR thickness of 0.4 mm provided a dose reduction comparable to or greater than that of the 0.25 mm lead equivalent, whereas the TCR thickness of 1.0 mm or greater provided a dose reduction comparable to that of the 0.35 mm lead equivalent.

CONCLUSIONS

Achieving a reduction of 95% or more requires the 0.25 mm lead equivalent for a distance of 100 cm, the 0.35 mm lead equivalent for 50 cm, the TCR thickness of 0.3 mm for 100 cm, or the TCR thickness of 0.9 mm for 50 cm. Without wearing a protective apron, a reduction of approximately 95% is observed at distances greater than 100 cm. These findings would be useful for medical staff engaging in related activities.

Preparation of Core–Shell Structure W/Gd2O3 and Study on the Properties of Radiation Protection Materials

W/Polydopamine (PDA) was prepared by adding W powder into the dopamine (DA) solution and adjusting the pH value of the solution. PDA contains several phenolic hydroxyl and amino groups, which provide abundant active sites for the complexation of metal ions. Therefore, we prepared W/Gd2O3 with core–shell structure by self-assembly method and homogeneous precipitation method, respectively. At the same time, polyurethane (PU) coating fabrics with W and Gd2O3 mixed powder and core–shell W/Gd2O3 powder were prepared, and their X-ray protection performance was tested. Results show that compared with W and Gd2O3 mixed powder PU coating fabrics, the protection efficiency and lead equivalent of core–shell structure W/Gd2O3 powder PU coating fabrics against different energy rays are obviously improved. With the increase in incident energy, the protective efficiency of core–shell structure W/Gd2O3 powder PU coating fabric decreases more slowly than that of W/Gd2O3 mixed powder PU coating fabric. When the incident energy is 65–100 keV, the protective efficiency of the core–shell structure W/Gd2O3 powder PU coating fabric is above 60%, showing a good synergistic protective effect. When the incident energy is 83 keV, the X-ray protection efficiency of core–shell W/Gd2O3 powder PU coating fabric is 65.5%, and the lead equivalent is 0.4051 mmPb.