MRI stands for Magnetic Resonance Imaging, which is a very safe, noninvasive medical imaging procedure that has been performed millions of times to date. MRI is different from X-ray, computerized tomography (CT), and positron emissions tomography (PET) because it does not use ionizing radiation to take pictures of the body. Instead, MRI uses a strong magnetic field and radio frequencies (RF), similar to the radio frequencies used by your cordless/cell phone, car radio and garage door opener. The images from MRI scans are much more detailed than what can be obtained from traditional X-rays or CT scans.