What type of filter is used in CT to compensate for a cylindrical shape of the body?

The bow-tie filter is specifically designed to compensate for the cylindrical shape of the human body in computed tomography scans. This type of filter is shaped like a bow-tie, which helps to reduce the radiation dose to areas that are closer to the center of the cylindrical scanning field, such as the abdomen or thorax, while allowing more radiation to reach the peripheries, like the limbs. This ensures a more uniform dose distribution and improves image quality by minimizing the problems associated with variations in tissue density.

By shaping the filter in this manner, it also helps to correct for beam hardening effects that can occur due to the differing densities of tissues, leading to enhanced contrast and clearer images. The design is essential for optimizing the balance between image quality and patient safety during CT examinations.