Obviously I'm expecting someone technical to answer this...but just what is the difference between them all? PET
Definition
Positron emission tomography (PET) is a highly specialized imaging technique using short-lived radiolabeled substances to produce powerful images of the body's biological function.
Purpose
Besides being used to investigate the metabolism of normal organs, PET has also become the technique of choice to investigate various neurological diseases and disorders, including stroke, epilepsy, Alzheimer's disease, Parkinson's disease, and Huntington's disease. Various psychiatric disorders, such as schizophrenia, depression, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, and Tourette syndrome, are also imaged by PET.
PET is especially useful in the context of cancer because it can detect metastatic tumors that may not be visualized by other imaging techniques. It is also being increasingly used not only as a cancer diagnostic tool, but also to help physicians design the most beneficial therapies. For example, it may be used to assess response to chemotherapy. PET imaging is very accurate in differentiating malignant from benign cell growths, and in assessing the spread of malignant tumors. PET is also used to detect recurrent brain tumors and cancers of the lung, colon, breast, lymph nodes, skin, and other organs.
CT SCAN
Computed tomography (also known as CT, CT scan, CAT, or computerized axial tomography) scans use x rays to produce precise cross-sectional images of anatomical structures.
Description
With the development of modern computers, the scans enhanced digital capabilities allowed the development of computed tomography imaging (derived from the Greek tomos, meaning "to slice"). The diagnostic potential of CT scans was first realized by English physician Godfrey Hounsfield.
CT scans differ from conventional x ray by collecting x rays that have passed through the body (those not absorbed by tissue) with an electronic detector mounted on a rotating frame rather than on film. The x-ray source and collector rotate around the patient as they emit and absorb x rays. CT technology then utilizes advanced computer-based mathematical algorithms to combine different readings or views of a patient into a coherent picture usable for diagnosis. CT scans increase the scope and safety of imaging procedures that allow physicians to view the arrangement and functioning of the body's internal structures. With particular regard to neurology, CT scans are used to determine the presence or absence of brain tumors. CT scans usually take about an hour and a half, including preparation time, with the actual examination of neural tissue in a brain scan taking 15鈥?5 minutes.
CT scanners are now often combined with positron emission tomography (PET) scanners into one unit. PETCT scanners have the ability to link the functional image created by a PET scan with the anatomical image produced by a CT scan. The combined scanning technique enhances a physician's ability to detect metabolic abnormalities (some no larger than 0.15 in [4 mm] in size) and to precisely map the location of the anomaly.
Increased accuracy reduces the number of unusable results and also results in less retesting.
The combined PET-CT scanners offer physicians the opportunity to differentiate, for example, between Alzheimer's disease and multi-infarct dementia. In addition, the enhanced images allow the differentiation of brain tumors from cerebral necrosis.
MRI
Magnetic resonance imaging (MRI) scanners rely on the principles of atomic nuclear-spin resonance. Using strong magnetic fields and radio waves, MRI collects and correlates deflections caused by atoms into images. MRIs (magnetic resonance imaging tests) offer relatively sharp pictures and allow physicians to see internal bodily structures with great detail. Using MRI technology, physicians are increasingly able to make diagnosis of serious pathology (e.g., tumors) earlier, and earlier diagnosis often translates to a more favorable outcome for the patient.
BONE GALLIUM SCANS
Radionuclide bone scan or bone scintigraphy.
Purpose
* To detect or rule out bone cancer when X-rays reveal no abnormalities but a malignancy is suspected.
* To detect bone infection.
* To determine the location of an abnormality before bone biopsy or surgery is performed.
* To diagnose stress fractures that do not always appear on X-rays. http://www.petscaninfo.com/http://www.cancerhelp.org.uk/help/defaul...
Read about them
http://www.medicinenet.com/cat_scan/arti... MRI - Uses a big magnet to align Hydrogen particles in your body. When that happens, the magnetism allows them to see a picture of your internals.
CT - Uses iodine as a contrast material to make you light up like a light-bulb to get an image
PET - Uses special radioactive glucose (instead of iodine) as a contrast in your brain but otherwise works like a CT.
Bone/Gallium: Also uses radioactive contrast material to let you see your bones. |
