Difference between MRI and PET scan

MRI, or magnetic resonance imaging, and PET, or positron emission tomography, are techniques that are designed to create images of what is going on inside the human organism. PET works via detecting emitted gamma rays, while MRI utilizes magnetic waves and radio waves to produce images. Both technologies are sometimes used in conjunction to deliver a comprehensive picture of the subject of medical investigation. There are several differences between MRI and PET types of scanning. We will take a closer look at them.


MRI vs PET scan
MRI scanning machine

MRI, or magnetic resonance imaging, is a well-established technique in modern medicine. MRI allows for scans of the human insides with the help of magnetic waves and radio waves. Due to the efficacy of the technique, it is now omnipresent throughout the world. MRI is essential in the diagnosis of a vast number of diseases.

PET scan
PET facility with PET scanner

PET scan, or positron emission tomography scan, is a functional imaging technique. PET gets the images of the inside of the human body utilizing tracer positron-emitting radionuclide.  The resulting images are combined in the following stage into a three-dimensional composite image of high quality. A PET-scan is  widely used for solving oncology-related issues.

Comparison chart

MRI PET scan
No radiation or other risk Potential radiation risk
Costs from $1000 to $4000 Costs from $3000 to $6000
Comparatively quick procedure. From 10 minutes to 2 hours. Slow procedure. Takes from 2 to 4 hours.

MRI vs PET scan

What is the difference between MRI and PET scans? Let’s compare them by potential hazard, costs of the procedure and the time it takes to perform the procedure.

  • There is no radiation hazard risk for the patients undergoing an MRI scan.  A PET scan, on the other hand, is a procedure with a certain level of radiation involved. The levels of radiation received by patients during a PET scan are comparable with the level of radiation received during a X-ray procedure.
  • The price of an MRI scanning procedure varies from $1000 to $4000. The PET scan procedure is twice as expensive as the MRI procedure on average.
  • An MRI procedure can be as quick as 10 minutes. PET scanning takes much longer to be performed, from 3 to 4 hours.


In this video you can see an analysis that reveals differences between MRI and PET scans: