Department Of Diagnostic Radiology

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Frequently Asked Questions
1.	Patient Preparation
2.	What happens when I arrive for my scan?
3.	What is a PET-CT?
4.	What is a radiopharmaceutical?
5.	What is FDG?
6.	Is a PET-CT scan painless?
7.	Is PET-CT safe?
8.	How long is the procedure?

1.	Patient Preparation
	1.	Bring recent examination films or studies (such as CT, MRI, ultrasound, PET) for the radiologist to compare directly to your PET-CT scan.
	2.	Do not eat or drink anything for 6 hours before your procedure, with the exception of water, Black coffee or tea, both without sugar or cream/milk. Do NOT take any sweets, flavoured/sugared drinks, mints, coffee with cream or milk, chewing gum etc., as it may interfere with the results.
	3.	Avoid strenuous/repetitive physical activities or exercise on the day before and day of your PET/CT exam. Excessive muscular activity may interfere with the interpretation of your exam.
	4.	Be well hydrated. Take plenty of water before your examination.
	5.	You may continue to take prescribed medications with water, but avoid over the counter medications that contain sugar like cough syrup.
	6.	If you are a diabetic, please notify our staff to obtain special instructions. If you take insulin to control your diabetes, you will be scheduled for an early morning appointment since you must withhold your insulin prior to the exam.
	7.	If you have any allergic history or have had an allergic reaction to intravenous contrast agent during your previous CT or X-Ray examinations, please notify our staff before your appointment.
	8.	Females who are pregnant or breast feeding should not undergo the PET-CT exam.
	9.	If you have any other special conditions or illness, make sure our staff is aware of that ahead of time.
	10.	Plan to arrive a little early. Allow 2-3 hours for the PET-CT procedure. The actual scan time (lying on the imaging table) will be less than 30 minutes. The standard exam varies depending on the type of study.
	*Note:* A very expensive FDG radiopharmaceutical has to be prepared specifically for your exam procedure. If you cannot keep your appointment, please notify us at least the day before the scan, otherwise you would be charged $3,000 for the cost of the ordered FDG radiopharmaceutical.

2.	What happens when I arrive for my scan?
	*At Queen Mary Hospital*
	1.	Come to the University of Hong Kong’s PET-CT Imaging Unit reception area located on the Ground floor of New Wing D, Main Building of Queen Mary Hospital.

	*At PET-CT Imaging Unit*
	2.	Report to the staff at Reception Counter. You would be shown to a change room where a locker has been reserved for you to place you belongings.
	3.	After changing, you will be waiting in a private Patient Preparation Room, where our Radiographers will discuss the procedure with you and answer any queries.
	4.	You will have an intravenous catheter placed into a vein in your arm for ease of injection.
	5.	Your blood sugar will be tested and if the levels are acceptable, the procedure will begin.
	6.	We will be injecting a small amount of a radioactive glucose or sugar known as FDG through this intravenous catheter.
	7.	Wait quietly in this private room for 45 minutes to 1 hour . It is important that you relax and rest and refrain from too much movement, talking or reading during this time to allow the FDG to properly distribute throughout your body.

	*In the Scan Room*
	8.	After the FDG uptake procedure, you will proceed with the scan, which will take 15 to 30 minutes.
	9.	You will be brought to the scan room and asked to lie down on a comfortable scanner bed. The scanner bed will move slowly through the donut-shaped PET-CT scanner to acquire the information needed to generate diagnostic images.
	10.	You will be asked to lie still and breathe normally during the scan because movement can interfere with results.

	*After the Scan*
	11.	You will be asked to wait at the Patient Waiting Area when your PET-CT will be reviewed to make certain that all images are complete and no further imaging is required. You may then check out with the receptionist.
	12.	Unless you've received special instructions, you can eat and drink immediately. Increasing your fluid intake soon after the exam will assist in removing any residual radiopharmaceutical in your system. The radiopharmaceuticals used during your scan do not remain in your system for long, so there is no need to avoid contact with others. However, we advise that you wait for a few hours before getting too close to an infant or anyone who is regnant.

	*Reports and result*
	13.	Results will be sent to your referring physician.
	14.	You physician will explain the findings of your PET-CT exam and submit the following to you on behalf of our PET-CT Imaging Unit at your next scheduled appointment: a. 3 copies of the PET-CT exam report; b. 1 copy of colour print; c. 1 copy of film; and d. 1 copy of CD-ROM.

3.	What is a PET-CT?
	PET stands for Positron Emission Tomography, and PET-CT is the combination of two imaging techniques in one exam – a PET scan and a CT scan. The PET scan provides unique information about your body on a cellular level while the CT scan offers excellent anatomic information. Overall, the PET-CT scan helps physicians diagnose disease and better understand the exact location and extent of disease. That information allows physicians to develop the best treatment plan for the patient.

4.	What is a radiopharmaceutical?
	Radiopharmaceutical is a radioactive drug. The most commonly used PET-CT radiopharmaceutical is FDG, which is a radioactive form of glucose (sugar). Radiopharmaceuticals are produced in very specific cyclotrons by physicists and chemists.

5.	What is FDG?
	2-Deoxy-2-[18F]fluoro-D-Glucose, or FDG, is a type of glucose (sugar) and is the most common radiopharmaceutical used in PET. To begin the PET procedure, a small amount of FDG is injected into your bloodstream through an intravenous catheter. Glucose is a common substance that every cell in your body needs in order to function and therefore will be taken up by cells. Diabetic patients do not need to worry; it would take 4,000 doses of FDG to equal the glucose in 1 teaspoon of sugar. FDG has a half-life of approximately 110 minutes, so it is quickly expelled from your body. FDG must pass multiple quality control measures before it is used for any patient injection.

6.	Is a PET-CT scan painless?
	The only pain involved is the needle prick when a small intravenous catheter is set up for you to receive the radiopharmaceutical injection.

7.	Is PET-CT safe?
	The risks associated with a PET-CT scan are very minimal. The quantity of radiation is low (10-25mSv) and the radiopharmaceutical (FDG) degrades quickly so that no detectable radioactivity is present after several hours. In addition to the radioactive decomposition, the remaining FDG is eliminated from the body through urine. Family members are not at risk of significant exposure since greater than 60% of the radioactivity has left the body or is decomposed before the patient has left the center.

8.	How long is the procedure?
	It depends on the type of PET-CT scan your doctor ordered. In general please allow 2-3 hours for the entire visit. This includes time to prepare you for the scan and time in the scanner.