STUDY OF MATERIALS FOR THE CONSTRUCTION OF PHANTOMS FOR RADIODIAGNOSTIC TESTS

In this study were analyzed different polymeric materials and composites that have X-ray absorption characteristics similar to the human tissues. These materials will be used to develop phantoms for radiodiagnostic tests. The development of phantoms using these materials is important in dosimetry studies, image quality evaluation and optimization of radiodiagnostic acquisition protocols. The X-ray absorption was measures using the Hounsfield scale (HU) obtained by CT image, and these values were compared with typical values of human tissues. The homogeneity of the materials was done through the noise analysis of CT images. The test cylinders are 2.5 cm in diameter and 2.5 cm long and were constructed from solid water, Polyethylene, high and low viscosity polyester resin, ethylene-vinyl acetate (EVA) and others additional components. The cylinders were placed in a polymethyl methacrylate (PMMA) head phantom and the images were generated using a head CT protocol. The scans were performed on a General Electric CT scanner with 64 channels. The scanner was programmed in helical mode with image acquisition parameters and was performed using 120 kV, 100 mA.s and 1 cm of slice thickness reconstruction. The tested mixtures were found in the range of soft tissues and lungs. By making different mixtures of materials, it is possible to build different equivalent human tissues. The noise percentages found in the CT images are within the expected values used in the diagnosis.