Determination of the Build-up factors and Linear attenuation coefficient of MCP-96 alloy for its use as Tissue Compensators in Radiation Oncology

In the present work an attempt is made to determine the Build-up factors and linear attenuation coefficient of MCP-96 alloy for dose correction in radiation oncology and radiation protection, using Co60 and Cs137 gamma emitters. A narrow collimated beam of ã rays obtained from Co60 and Cs137 are passed through various thickness of MCP-96 alloy and the attenuation in the intensity of the beam is determined for every block of MCP-96 alloy. The thickness of the blocks varies from 0.5 cm up to 6 cm in a 4cm x 4cm shape. Plotting the thickness of the alloy and the corresponding intensity of the beam allowed us to determine its linear attenuation coefficient. The narrow beam geometry is then replaced by broad beam geometry by removing the collimator and the radiation beam is able to interact with the MCP-96 alloy at all possible positions facing the radiation source. Additional radiations obtained by the detector as a result from the scattering of radiation develops the build-up factor. The buildup factor is then calculated using the attenuated beam received by the detector in the broad beam geometry and in the narrow beam geometry. The buildup factor is found to be dependent on the thickness of the MCP-96 attenuator, the solid angle and the source to attenuator distance. Buildup factor is plotted against the thickness of MCP-96 alloy, energy of the radiation beam and the solid angle of the geometry. These values are providing ways for dose correction in radiation oncology and radiation protection when MCP-96 is used as tissue compensator or for radiation protection purposes.