A new method for the evaluation of radiotherapy 3D polymer gel dosimeters has been developed using ultrasound to assess the significant structural changes that occur following irradiation of the dosimeters. Polymer gel dosimeters were being fabricated using a monomer named 2-Hydroxyl-Ethyl-Meta-Acrylate (HEMA) with the presence of gelatine as a gelling agent. The readymade gel which is the concentration for HEMA fixed at 2, 4 and 5% would then undergo an ultrasonic evaluation to test for the propagation of sound speed through it. In the observation of relationship between the ultrasound propagation speeds as the doses increase (focusing at the cross region from overlapped beams) and concentration of monomer, the propagation speed for all the three polymer gel dosimeter phantoms still varies between 1460 to 1570 m/s which is still in the range of speed of sound for human tissue [. The ultrasonic absorption attenuation coefficient dose sensitivity for polymer gel dosimeters for 2, 4 and 5% of monomer are in the range of 0.02 to 0.6 dB which is equivalent to human tissue. As a comparison, it can be seen that gel phantoms with high concentration of monomer (5%) is more sensitive to the radiation compared to the lower (2% and 4%) concentrations. Regarding the absolute results of mechanical and acoustic properties; the copolymer-in-oil phantom is equivalent with soft tissue.

Concrete is a common material used to build physical barrier as protection against ionized radiation. However, excessive used of concrete may lead to increase volume on mining of cement and sand, thus contribute to catastrophic on nature. This project is done to find suitable material that can replace the usage of concrete in order to build physical barrier for radiation shielding. Hence, combination of Kaolin clay and eggshell powder are chosen as these materials are cheap, biodegradable and eco-friendly. Two main types of sample blocks are prepared: concrete and clay blocks. The portion of eggshell powder are varied, with increment of 1/10 cups for each sample. All samples are exposed on 60, 80 and 100 kVp of x-ray energy and absorbed dose were recorded. Results shows that blocks with adding eggshell powder contribute to greater value of radiation absorption ratio compared to blocks with non-added of eggshell powder. In addition, Sample 4 (consist of 4/10 cup of eggshell powder) were found to be the suitable portion due to optimum value were seen between these concrete and clay blocks. Hence, the clay blocks with additional of eggshell powder can be used to replace the usage of concrete for radiation shielding building.

No abstract

No abstract

No abstract