PET-CT

 
Institute Director: Dr. Moshe Bocher

 

 

Explanation for a patient undergoing a PET-CT examination:
PET-CT combines two technologies, PET and CT; the latest instruments are very fast and can scan large areas in a short time. The test is painless and the patient will lie in the camera for just 10-20 minutes.
PET - Positron Emission Tomography (PET) is a scan based on the injection of a minute amount of radioactive material into the vein. This material is absorbed into the body and is then identified and photographed by the PET scanner, which can pick up the minimal radiation emitted from the marker, and thus track the physiological and molecular condition of the patient. The most common marker used is FDG, a sugar which is fluorine-marked 18.

CT (Computed Tomography) is a computerized anatomic-radiographic scan of tissues and organs that can detect disease conditions, mainly by identifying structural changes in body organs. In some cases, iodine is injected which gives a clearer picture. It is therefore important to inform the technician of sensitivity to iodine or other substances, of an asthmatic condition or kidney dysfunction.
 In recent years, PET-CT with the FDG marker has become a leading diagnostic tool for various cancers, determining their dispersion in the body, and evaluating their response to treatment. In addition, the test has been found to be effective in detecting infections and is used as part of a neurological examination of diseases such as epilepsy, neurodegenerative diseases, heart disease, and more. Along with the FDG marker, we sometimes use other markers, for example, to track prostate tumors.

PET testing procedure:
From the time you enter the PET-CT unit, the procedure usually lasts no longer than 3 hours. An hour before the start of the test you will be injected with the radioactive material (usually FDG). During the waiting period you will be asked to rest in an armchair, and you should avoid excessive activity, talk and use of a mobile phone. Do not leave the waiting room after the injection. While waiting, you will be instructed to start drinking a contrast agent - one glass every 10 minutes (for a clear picture of the bowel) and you may use the adjacent toilet. In any case, before you begin the examination, you will be asked to empty your bladder. Prior to the scan you will also be asked to remove your jewelry, belts and any metallic object on your body. The technician will place you comfortably on the scanner bed, which is electronically powered, and once the technician leaves the room for the control room next door, and informs you that the test is beginning, the bed will automatically move forward into the space of the instrument. During the test you can communicate with the technician even when he is in the control room next door; he can see you both directly and through a wall camera. The first stage is the CT scan which will take about 2 minutes. It is possible that during the course of the procedure, you will be injected with a contrast substance (iodine) into the vein, which may cause you to feel warm. The PET scan will then take about 10-20 minutes. Once the procedure is completed, wait for a technician to help you get safely out of bed. After a short monitoring period, you will be released from the Institute.

How to prepare for the test:
• A referral must initially be sent by a specialist, including a financial commitment.
• If undergoing chemotherapy, you should wait for at least two weeks after the last treatment. After radiation treatments, you should wait at least 6 weeks. In exceptional cases, consult your referring physician and inform us.
• Patients treated with Gleevec should check with their referring physician in advance if they want the test to be performed after a two-week discontinuation of the drug or while taking it.
• If you are receiving corticosteroids, consult your doctor about timing, and inform us about your steroid treatment.
• The test can be performed during hormone therapy and during bisphosphonates treatment.
• In the case of biological treatments, it is recommended to wait as long as possible following the last treatment, in coordination with the referring physician.
 •If taking medications to increase white blood corpuscles, it is recommended to wait 7-10 days for Neupogen and 14 days for Neulastin.
Diabetics coming to be tested should preferably have sugar values of up to 150 mg; higher sugar values may impair the reliability of the test. It is important for diabetics to mention their condition when making an appointment, to receive an explanation and information on preparation for testing.
• Diabetic patients taking Metformin should consider discontinuing the drug for 48 hours before a test involving iodine contrast, but only in coordination with the referring physician. If an iodine contrast agent is indeed administered during the test, a blood test for creatinine should be performed before returning to the drug.
• It is important to avoid strenuous physical activity for 48 hours prior to the test.
• Please arrive with the results of a blood test checking renal function, taken within the month prior to the appointment.
• Fast for at least 4 hours before the test. Drink only water. Do not chew gum / eat candies during the 4 hours preceding the test (even if they are sugar free). Do not drink sugary drinks or alcohol the night before the test. In the case of a hospitalized adult patient receiving intravenous solution, there should be no sugar in the solution for at least 4 hours preceding the examination. For small children, instructions will be given separately.
Please bring copies of any previous CT, MRI, and PET-CT. Please bring discs and interpretations if performed at another medical center.
• Avoid arriving with jewelry or valuables, and any metallic objects on your body on the day of the test.
• Medicines can be taken as usual, provided they do not contain sugar, and only with water.
• Those suffering from claustrophobia should consider taking a sedative prior to the test, upon the advice of the referring physician. In that case, it is advisable to avoid driving after the procedure, and if necessary, to arrive with a driver. This is written as a matter of caution: the camera is open on both sides, and there is usually no problem for the subjects to lie in it.
• It is important to arrive at the reception office at the scheduled time. Late arrivals may forfeit their appointment. Duration of stay at the Institute is up to 4 hours.
• In case of cancellation or delay, please call us immediately at 04-6828841 / 2. You can leave a message if the office is closed; please leave a phone number so we can contact you. You are welcome to call us with any further questions you may have.

FAQ:
May I be in contact with other people after been injected with the radioactive marker?
Yes. The radiation emitted from the body is minimal and does not endanger you or the people around you.

Will I be injected with iodine-containing contrast?
In many cases, we want to inject an iodine contrast material to improve the quality of the test. The substance will not be injected if it is not needed, or if you are sensitive / allergic to it, if you suffer from kidney disfunction or any other problem that the doctor will decide not to inject iodine. If you are to be injected, the technician and nurse will inform you in advance. If you know that the injection is not appropriate for you, you must inform us.

Can the test be performed during pregnancy?
In general, tests involving exposure to radiation are not recommended during pregnancy. Therefore, if you are pregnant or there is a reasonable possibility that you are pregnant, it is quite possible that the test will not be performed. You must report your pregnancy to the doctor or to the Institute technician prior to beginning.

Is it permissible to breastfeed after a PET-CT test?
The first day after the mapping, a small amount of the radioactive material is excreted in the mother's milk. Therefore, breastfeeding should be discontinued for 24 hours, after which you can resume breastfeeding without fear. During the first 24 hours following the test it is recommended to pump the milk and dispose of it.

 Are there side effects to the test?
There are no known side effects after PET.
Side effects after injecting a contrast agent are known, as in similar CT scans.