| PET - CT |
| |
What is PET-CT? |
| |
PET is a unique noninvasive imaging system that shows how an organ /tissue functions in the body and localizes abnormal metabolic activity in the body. In contrast CT provides only anatomical/structural information of organs or tissues abnormalities. |
| |
A combination of functional and anatomical localization obtained by a single investigation has the advantages which could be otherwise obtained by two separate investigations, that is PET and then CT scan done at different times and on different machines and probably at different centers.
The single investigation also helps in direct fusion and overlap of images obtained on a single machine of PET and CT images so that information of function is superimposed on the anatomy of the organ. This information greatly helps in a more focused and informed reporting of disease processes with lesser chances of errors. |
| |
How does PET work? |
| |
The human body is primarily made up of elements such as oxygen, nitrogen, carbon and hydrogen. These are the basic building blocks of molecules in the body and of the metabolic materials used by the body functions. If one can introduce radiolabeled molecules such as glucose which is used by the human body for energy production then any abnormality in the function of the body can be identified as the radioactivity helps to localize this information. The amounts of radioactivity used are very small and hence not hazardous to the person who is undergoing this investigation.
|
|
| |
Following an injection of this material and allowing a period for the equilibration in the body a scan is obtained to image the distribution and accumulation of the labeled glucose by the PET/CT scanner.
First CT images of the whole body or localized areas is acquired for a few seconds.
Immediately after PET images are acquired for a longer period of time depending on the areas to be scanned and the size of the individual. This may vary from 20-30 minutes during which period of time the patient needs to lie still without any movement under the machine. |
| |
The PET images which shows distribution of radioactive glucose in various organs will be fused/superimposed on the CT images and a combined information of structure and function of the organs or tissues is obtained. |
| |
Types of PET scans: |
| |
Whole body PET-CT scans |
| |
- Early detection of various types of cancers as metabolic changes precede structural changes
- Staging of cancers
- Monitoring the effects of cancer therapy (surgery, chemotherapy and radiotherapy)
- Differentiating between recurrences and radiation induced fibrosis/necrosis.
- Follow up for early detection of recurrences.
- Detection of infective foci in acute and chronic infections.
|
| |
Cardiac PET scans |
| |
Assessment of myocardial viability in the management of coronary artery disease. |
Brain PET scans |
| |
- Early detection of brain tumors
- Monitoring effects of treatment in brain tumors
- Differentiating recurrence of tumors from radiation necrosis/fibrosis.
- Dementias
- Epilepsy
|
Is PET/CT safe? |
| |
YES. PET/CT provides special information about diseases in a noninvasive manner. As with any medical procedure there is a very small risk involved. Very low levels of radiation exposure due to radioactive tracer is involved.
However, the radiation exposures are far below those obtained while undergoing a chest X-Ray or diagnostic CT scan. In other words, it is safer than an X-Ray or CT examination. Hence, the procedure can be done in infants and children also. |
| |
| |
|
