PET-CT Scan: Answers to frequently asked questions

PET (positron emission tomography) – CT (computed tomography) is an advanced imaging technique combining structural and molecular imaging. The most frequently performed is FDG PET-CT scan, which is based on glucose metabolism of cells. Hence, cells that consume more glucose (brain, heart, cancer cells) show more uptake on PET scan.

When is PET-CT scan advised?
There are oncology (cancer) and non-oncology indications for PET-CT scan. In cancer, it is used for detection, revealing where it has spread, checking whether cancer is responding to treatment and finding cancer recurrence early. 
Occasionally, some non-cancerous conditions may appear like cancer on PET, and some types of cancer may not be so apparent on PET images. These factors in relation to your clinical status will be taken into consideration by your treating doctor.
Non-oncology PET scan for heart can help your treating doctor decide whether you would benefit from coronary bypass surgery, and PET scan for brain is used in dementia, seizures, etc.

Pre-requisites for PET-CT scan
•    Schedule an appointment
•    Your fasting blood sugar level needs to be between 80 – 160 mg/dl
•    Recent Serum creatinine report
•    Fasting for 6 hours prior to scheduled appointment time. Drinking plain water is allowed unless you require      sedation/anesthesia for the scan
•    Avoid strenuous exercise for a few days prior to the scan
•    Bring your doctor’s prescription and also previous relevant reports and films

Procedure of PET-CT scan
•    When you arrive in the Nuclear medicine & PET-CT department at your scheduled appointed time, you will be initially attended to by a doctor to note down clinical history. It takes about 2-3 hours for the entire procedure. 
•    You will be provided hospital clothing and asked to remove all jewelry and metallic accessories. 
•    The nurse will secure an intravenous access. Your blood glucose level will be measured (If your blood sugar level is >200 mg/dl or <70 mg/dl, you may need to be rescheduled). 
•    A small amount of radioactivity will be injected through the i.v line and you will be asked to sit on a reclining chair for approximately 60 minutes. Try to relax and limit your movement during this time, and ask for a blanket if you feel cold. During this waiting period you will be asked to drink contrast solution. You will be asked to urinate just before your scan. 
•    PET-CT machine is a large machine and looks like a doughnut hole. It is not as enclosed as MRI, however inform the doctor if you are claustrophobic.
•    The scan duration is approximately 15-30 minutes. You may be administered contrast through the I.V line which may give a warm sensation. Some people can have an allergic reaction through I.V contrast. Inform the doctor if you have any history of allergies.
•    After the images are acquired, you will be informed if the scan is completed or any additional images are required. 
•    After the scan you can go ahead with your day as usual, and drink plenty of fluids.

Radiation risk in undergoing a PET-CT scan
For PET scan a radioactive drug/tracer will be injected into the vein. The amount of radiation exposure in the tracer is small. Hence the risk of negative effects from the radiation is low. It is not advised to undergo PET-CT scan during pregnancy.

FAQs:

Can breast feeding continue while undergoing a PET-CT scan?
Avoid breast feeding for 4 hours after your scan.

Can I undergo PET-CT scan if I am claustrophobic?
Yes. Inform the healthcare team prior to scheduling appointment, so that necessary arrangements for performing the scan under sedation/anaesthesia can be made.

When will the PET-CT results be available?
PET-CT report and images takes 2 to 3 working days. At P. D. Hinduja Hospital, it is available after 2 working days and can be collected at the report counter, ground floor, OPD building. The report will also, be sent to your registered e-mail address, if provided.

How to schedule a PET-CT appointment?
You can schedule an appointment or queries, please call 022-67668181 / 022-45108181 or 8291944367.