Abstract: Incorporation of filters between the X-rays source and the patient in Computed Tomography helps to optimize the radiation dose and prevent unnecessary radiation; however the filters use can act as a source of secondary radiation due to angular scattering. The process of X-rays scattering, the energy transmitted and the scattered photons from such filters has is presented. This shows that the scattered photons that can contribute to unnecessary radiation are due to Compton Scattering. Only by understanding and proper collimation of the X-rays, can it be useful in diagnosis without affecting image quality or contributing to unwanted radiation to the patient and laboratory staff.