Biology and Technology

Definition:
CT: computed tomography, uses x-rays and powerful computers to create cross section pictures of body

PET: positron emission tomography, uses a radioactive substance called tracer to look for diseases and shows how well tissues in body work

FMRI: functional magnetic resonance imaging, measures brain activity by monitoring changes in blood

How does each work?
CT: X-ray machine "scans" body, depending of which part is being scanned because radiation isn't healthy and is limited as much as possible by special covers. For some examinations a contrast dye is give to patient through IV, rectum or orally, depending on the examination, to make some parts to be clearer on the x-ray which can be in form of a photograph.





PET: The patient is given tracer, usually given through  IV, asked not to eat 4-6 before the test. After the traces is absorbed, the patient is laid on a table and put into a special tube. The tracer goes through various organs through the blood system and is visible on monitors in 3-D which help diagnose the patient. This method



FMRI: Measures the amount of oxygen in blood. The neural activity in brain requires oxygen. fMRI uses strong electromagnet to see which part of brain is working based on how much oxygen is being used. This happens in a tube machine in which the patient lays motionlessly.









What is able to be learned through the use of each?
CT:  Studying blood vessels, blood clots, broken bones, infections, stroke and bleeding in brain

PET: Brain function, cancer, heart problems, brain disorders

FMRI: Which part of brain is functioning

How can each be used to explain human behavior?
CT: May help unusual behavior by diagnosing patient as having a stroke. Another example is hydrocephalus ( build up of fluid in brain)common in old people and infants. The symptoms may be above all vomiting, irritability and sleeplessness.

PET: Helps to diagnose brain damage, dementia or tell the difference between Parkinson's or other movement disease. For example, PET may show the spiral way of how the brain cells die, which is symptom of Alzheimer's disease

FMRI: Scientists are able to go as far as "read mind" of a person by showing him/her a picture while in the machine, scanning which part of the brain is activated when the person thinks of this object/how to use it/ how to hold it/ his or her experience with it, and record this data. So far, people had very similar results for the same objects.


Sources:
http://www.nlm.nih.gov/medlineplus/ency/article/007342.htm
http://psychcentral.com/lib/2007/what-is-functional-magnetic-resonance-imaging-fmri/