<prompt> Which of the following is not an ionizing radiation:MammographyMRIAngiographyCT  <response>: Ans. B. MRIMammography It is an imaging technique exclusive for the breast. Mainly uses characteristic spectrum radiation originating from a molybdenum anode. It is generally done in females above 35 years of age.MRI Most commonly used magnet in MRI: Superconducting magnets. Stronger the magnet better the image resolution. MRI has no radiation exposure as X-rays are not involved.Angiography With the advent of cross-sectional modalities it is not used often. It can be used in some cases where vascular flow and other dynamic components are to be evaluated.CTComputed tomography is basically a fusion of two technologies: Tomography: X-ray based imaging technique developed to acquire sectional image of the body. Computers: Brought in to deal with the complex mathematical algorithms and iterations in the image reconstruction.As X-rays are used in this technique, there may be a chance of radiation. 