How Do Different Kinds of Medical Imaging Work?
There are many different kinds of medical imaging that doctors can use to build images of the inside of your body. They generally use electromagnetic or sound waves.
Here are some:
Thermal Imaging
Detects infrared rays coming from the person's body and measures body temperature.
Hotter areas can indicate a fever or tumour whereas colder areas can indicate poor circulation.
Risk to patient: low
X-Rays
Create images of the bone structure (appears white) and soft tissue (appears black or dark grey) in the body which can then be seen digitally.
Creates 2D images of the inside of the body.
More for bone injuries.
Risk to patient: low
Computed Tomography (CT) scans
Uses x-rays to create 3D images of the inside of the body as they rotate around it.
Is more detailed than x-rays, e.g. can detect small fractures in the bone.
More for bone injuries but recommended if a patient can’t have an MRI in an emergency.
Risk to patient: low but more than x-ray
Gamma Rays
The patient is injected with a drug of a short radioactive half-life and which is then traced with a gamma-ray scanner.
This then creates 3D images of the inside of the body.
Risk to patient: medium
Magnetic Resonance Imaging (MRI)
Uses high-frequency radio waves and a strong magnetic field.
This creates high-quality 3D images of the inside of the body in which tissue can show up.
More for tissue injuries.
Risk to patient: low
Ultrasound
Uses the high-frequency sound as the name suggests, ultrasound.
As the sound echos when density changes it can create low-quality images of the inside of the body.
Safe for pregnant women.
Can be done in real-time.
Risk to patient: very low
Links for further reading:
https://www.youtube.com/watch?v=0d_P5kXkAvE
https://www.youtube.com/watch?v=0q9wTyGhqFs
https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/ct-vs-mri-vs-xray
