Introduction to Imaging Flashcards
Describe how X-rays work
X-rays are absorbed by certain parts of the body then a film is exposed turning it black. Hence denser tissues where X-rays are blocked turn white.
Order of density of tissues and hence X-ray absorbtion
Common clinical uses of X-rays
Bone fractures
Bone disorders
Some soft hollow organs can be visualised using a contrast reagent
Disadvantages of X-rays
Soft tissues can’t be viewed unless a contrast reagent is used
Low resolution - can be blurry
Flatten 3D structures into 2D
What does CT/CAT stand for?
Computed Tomography
Computed axial tomography
What is CT/CAT?
X-ray tube and a recorder rotate around the patient taking multiple images. This then creates a detailed transverse cross section
Uses of a CT
Can be used to diagnose damage to internal organs, vessels and cancer
Can be used to plan operations
Advantages/ Disadvantages of CT
How does an MRI work?
Detects differences in hyrogen which is found in water
Magnetic fields align the hydrogen protons, radio pulses then knock these out of position and they emit waves as the align again
Ultimate image is developed based on differences in water content
MRI advantages and disadvantages
Ultrasound imaging
Produces high frequency sound that reflect off body tissues
Doppler Ultrsound
Uses the doppler effect to visualise flow and motion
Ultrasound advantages and dissadvantages
What does PET stand for?
Positron emission tomography
What does MRI stand for
Magnetic resonance imaging
