What is the difference between an MRI and a PET scan?

The main difference between an MRI and a PET scan is the way each method evokes the image that healthcare providers rely on. These scans are incredibly valuable in confirming and exploring possible diagnoses, without which doctors and other professionals would be less able to treat the disease effectively. Functionally, MRI and PET scanning act to penetrate peripheral structures to achieve similar goals; however, their methods of doing so differ. In a nutshell, an MRI uses magnetic technology, while a PET scan detects a substance in the body to produce an active image.

Both MRI and PET are acronyms. MRI is an abbreviation for MRI, while PET stands for Positron Emission Tomography. Although both terms can be intimidating to the layman, they are really very descriptive of what each scan accomplishes and how it does it.

MRI uses multiple magnetic fields, each very strong, to physically align specific atoms in internal structures of the body. These magnetic fields cause a rotational movement of the nuclei in the center of the atoms, and these variations are due to differences in location and the type of atom. These disparities in rotational speed are recorded and translated to form an MRI image. This image usually reflects an internal structure of the body. One of the strengths of MRI is its ability to illustrate discrete differences in soft tissue, especially the brain, heart, muscle, and growths.

MRI and PET differ primarily in modality. Although MRI uses magnetic fields, an active ingredient is the key to a successful PET scan. This substance is usually injected into a specific region of the body or ingested, and as this radio tracer breaks down, it emits positively charged particles, which are collected by specialized equipment. The differences in emissions show how the body's systems work. Functional differences can be expressed by different brightnesses and colors on the computed image.

It is important to realize that an MRI and a PET scan differ fundamentally in the way they acquire their images, as well as the circumstances in which they may be used. Taking and interpreting such images requires a great deal of knowledge, so only trained professionals should administer or draw conclusions from these tests. These tests are tremendously complicated procedures whose mechanical processes are only fully understood by those trained to do them.

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