The use of barium sulfate as a constituent of concrete for shielding of radiology rooms

ABSTRACT

Exposure to ionizing radiation is increasingly common in the routine of modern society, due to the advances in health practices. Thus, attention should be drawn to the mechanisms of radiological protection in order to minimize the radiation absorbed by individuals, especially in healthcare facilities. A radiology room must have adequate shielding, considering materials with the appropriate density and thickness. In this context, this study proposes a concrete specific for the construction of radiology rooms, using barium sulfate (barite) and basalt rock in its composition. The concrete has an average apparent density of 2.46 g/cm³, being classified as normal, according to its density, avoiding overload generated by its structure. During resistance to axial compression characteristic (fck) tests, the concrete reached the value of 102.90 MPa. This value represents an increase of 157% when compared to fck for a higher class of environmental aggressiveness (40 MPa), as provided in NBR 6118. For the radiation shielding tests, 5 prismatic samples with area 10 cm x 10 cm, and thicknesses varying from 2 mm to 10 mm, were molded. The shielding efficiency was measured by an ionization chamber, positioned below the samples, for different energy values of the X-ray beam (60, 90 and 125 kVp). The results indicate that even for 125 kVp, one of the highest values used in most radiology equipment, a thickness of 16.70 mm is sufficient to block 95% of X-radiation, as recommended by the Federal Ordinance No. 453 of Anvisa. This set of factors, in particular its shielding capacity, shows that the proposed concrete is suitable for applications in radiology room shielding.

Keywords
Barium sulfate; shielding; radiology; ionizing radiation