A&P - 1.7 Medical Imaging

x-ray

• high energy electromagnetic radiation

• slightly blocked by the soft tissue and fully blocked by bone or teeth resulting in a white “shadow”

computed tomography (CT)

• generates multiple x-rays as it rotates around patient (large radiation exposure)

• x-rays assembled to create a very detailed image

• soft tissue masses can now be measured to the millimeter

magnetic resonance image (MRI)

• electromagnets and radio waves

• good for softer things like the brain

positron emission tomography (PET)

• radioactive contrast travels to areas with high metabolic activity (such as cancer)

• isotope breaks down causing photons to be released and detected by scanners resulting in an image

• reveals metabolic and physiological functions in tissues

difference between CTs, MRIs, and PET scans

PET scans show us activity within our bodies (physiology) while CT and MRIs show us structures (anatomy)

ultrasonography

• high frequency sound waves

• visualize body structures such as tendons and organs

• commonly used to monitor pregnancy