POSITRON EMISSION TOMOGRAPHY – Definition, Purposes, Principle, Instructions, Preparation of the Client, Procedure, After Care, Advantages and Disadvantages (NURSING PROCEDURE)
Positron emission tomography (PET) was developed in 1970’s, it is a noninvasive technique that is useful in studying biochemical and physiological function in a living organism such as glucose uptake and metabolism, oxygen uptake and cerebral blood flow pattern
DEFINITION
- Positron emission tomography scanning is a type of radioactive substance is introduced into the body to assess structure and functions of tissues
- Positron emission tomography is a computer-based nuclear imaging technique that can produce pictures of actual organ functioning. The patient either inhales a radioactive gas or is injected with a radioactive substances that emits positively charged particles
PURPOSE
- To study heart and brain
- To locate the origin of epileptic activity in the brain
- To detect coronary artery disease
- To assess myocardial viability
- To assess the progress of coronary artery stenosis
- To differentiate ischemia and dilated cardiomyopathy
- To measure cerebral blood flow and cerebral glucose metabolism
- To chart the progress of Alzheimer’s disease, Parkinson’s disease, head injury, schizonphrenia and manic depressive illness
PRINCIPLES OF PET
- The technology is based on the use of an online cyclotron (electromagnetic machine) and positron emitting radionuclide is created
- The patient inhales or injected with a compound that has been labeled with a positron emitting nuclide ‘tag’ (often carbon 11) once inside the body, the compound selected concentrates in the area of clinical interest and emits positrons that reacts with electrons producing gamma rays of specific energy
- A special scanners detects the gamma rays and encodes the data into a computer which reconstructs cross-sectional images of the tissue containing the labeled compound
GENERAL INSTRUCTIONS
- Explain the procedure to the patient clearly
- Client is asked to fast 4 hours prior to the scan
- Check the blood sugar if it is below 150 g/dL for diabetic
PREPARATION OF THE CLIENT
- Explain the procedure to the patient
- Check if the client had food within 4 hours prior to the procedure
- Maintain NPO for 6 to 12 hours before the procedure
- Check the blood sugar of the client
- No glucose solution, intravenous should be used
- Ask the client to empty the bladder prior to the procedure since it is for 2-3 hours
PROCEDURE
- After 6-12 hours of nothing per oral, the client is placed on a stretcher in the imaging center and prepared
- An arterial line may be inserted to draw blood samples for measurement of cerebral metabolic rate
- The radio pharmaceutical agent of choice is injected via venous access
- The patient rests quietly in a dimly lighted room for about 45 minutes while uptake of the drug occurs
- If the blood sample is required, it is drawn quietly without disturbing the environment
- The scanning procedure takes 45 minutes; the entire procedure takes about 2-3 hours
AFTER CARE
- Check the vital signs and record
- After completion of the study, fluids should be encouraged to clear the radioisotopes from the body
ADVANTAGES
Images through the procedure are very clear in comparison to the conventional scans
DISADVANTAGES
- It is an expensive study
- Online-cyclotron equipment is found only in a few major research centers
- It is used for diagnostic purposes for only a limited number of clients
