Types of Imaging Used To View Patients : MRI and PET scan

Different types of imaging: X-ray, ultrasound, computerized tomography scan, MRI, SPECT scan, PET,  Bone density tests.

From "Information technology in Radiology"

Lillian Burke Barbara Weill

MRI-Magnetic resonance imaging

Magnetic resonance imaging machines use computer technology to produce images of soft tissue within the body that cannot be pictured by traditional x-rays. Unlike CT scans, MRI’s can produce images of the insides of bones. Using a technique called  scientific  visualization, MRI machines use computers an d a very strong magnetic field and radio waves to produce pictures. The images are constructed from mathematical data  generated by the interaction of radio waves and the protons inside the nuclei of hydrogen atoms in the water and fatty tissue  in the human body. The MRI machine creates a magnetic field many times stronger than the earths, it then generates radio waves.  The response of the bodies cells is measured by a computer, which then uses this data to create an image. MRI is more accurate than other imaging methods for detecting cancer that has spread to the bone although PET; CT scans find cancer of the lungs more accurately. MRI’s may be used for diagnosis and for the treatment of certain conditions that used to require surgery. For example, using MRI, radiologists can now clean or close off arteries without surgery. MRI’s do not use radiation and are non-invasive. It can distinguish between different types of nerve tissue.

Relatively new, functional MRI’s, measure small metabolic changes in an active part of the brain. MRI identifies brain activity by changes in blood oxygen. 

Positron Emission Tomograpgy -PET

PET scans use radioisotope techmologyto create a picture of the body in action. PET scans use computers to construct images from the emission of positive elections (positrons) by radioactive substances administrated to the patient. PET scans, unlike trad.itional Xrays an d CT scans produce images of how the body works, not just how it looks. PET scans may help detect changes in cell function (disease) before changes in structure can be seen by other imaging techniques. PET scans are used to study Alzheimer’s, Parkinson’s, epolipespy, learning disabilities, moral reasoning, bipolar disorder, and cancer. PE scans are also used to diagnose arterial obstructions. They are accurate and can avoid invasive catheterization. 119 

PET scans can show functioning of the brain by measuring cerebral blood flow. The scans produce a picture of activity, of function. A person is administrated a small amount of radioactive glucose. The area of the brain that is most active uses the glucose more quickly…