PET / CT provides clarity and precision

Positron Emission Tomography, or PET, is one of the newest diagnostic imaging procedures. It produces three-dimensional images of the body which highlight certain abnormalities, particularly cancerous tissues.

Examinations with our equipment are helping doctors to make more precise determinations about the effective treatment of cancer and certain heart problems. The results of an examination show the effect of current treatment and permit the adjustment of treatments to meet the current status of the disease process. This is known as the staging and restaging of treatments.

PET/CT equipment is somewhat deeper from front to back in order to accommodate two types of scanning components in one housing. The Positron Emission Tomography (PET) scanner detects faint emissions produced by radioactive "tracer" isotopes in glucose as it is metabolized by the body (see more on this below). These emissions are detected by sensors in the machine and plotted in the system computer to form an image.

The CT scanner inside is essentially the same as other high-resolution CT machines. It takes a large number of X-ray pictures from many angles and assembles them in the same system computer where they are merged into a single picture with important details on structures of interest to your doctor.

PET / CT PET scans are performed to:

• Detect cancer
• Determine the how much a cancer has spread in the body
• Assess the effectiveness of a treatment plan, such as cancer therapy
• Determine if a cancer has returned after treatment
• Determine blood flow to the heart muscle
• Determine the effects of a heart attack, or myocardial infarction, on areas of the heart
• Identify areas of the heart muscle that would benefit from a procedure such as angioplasty or coronary artery bypass surgery (in combination with a myocardial perfusion scan).
• Evaluate brain abnormalities, such as tumors, memory disorders and seizures and other central nervous system disorders
• Map normal human brain and heart function

What is a PET/CT Scan?
Positron Emission Tomography /Computed Tomography, or PET/CT, is a dedicated scanner which incorporates both PET and CT technology into a single unit. PET/CT is a whole body scan that can effectively detect and evaluate many types of cancer earlier and more accurately than any other imaging tests. PET/CT is also helpful in diagnosing certain neurological conditions such as uncontrollable seizures or Alzheimer’s disease.

Performing PET and CT with one scanner produces perfectly superimposed images so that metabolic abnormalities seen on PET can be precisely localized to a specific anatomic structure shown on CT. Such distinctions can make all the difference in arriving at a correct diagnosis.

This machine provides a very accurate picture of what's going on inside. Merged pictures can be compared to a radar weather map of the United States that shows weather fronts and storms over outlines of each state.  The more doctors know about what's going on inside your body, the better they are able to manage treatments. The specific advantage of merging two types of images is the ability to see cellular activity and very precise location of that activity in one picture.

What are the benefits of PET/CT scanning vs. other imaging?

• PET/CT often identifies disease sooner and with more accuracy
• PET looks at the metabolic information of your cells and tissue; CT scans look at the anatomy and structure
• PET/CT can help determine if a tumor is cancerous or benign; and also detects and differentiates a tumor from scarring caused by surgery or radiation treatment
• PET/CT scans can reduce, replace, or eliminate multiple imaging exams, and may help avoid invasive or unnecessary procedures
• Disease is detected, staged, and re-staged with greater certainty and confidence
• Increased diagnostic precision helps insure optimal treatments and outcomes for our patients

What does the PET/CT scan entail?
The first part involves an injection of a small amount of a positron-emitting form of glucose. Glucose is a sugar every cell in your body needs in order to function. You will relax comfortably in a room for approximately one hour while the radioactive sugar circulates and localizes throughout your body. You will then proceed with the PET/CT scan.

The scan lasts about 20 to 25 minutes and involves lying on a table which passes through the scanner. After the scan you are ready to leave the clinic. Your appointment will take approximately 2 hours.

You should arrive at the center approximately 15 minutes before your appointment time for the usual screening procedures and paperwork. Before your exam, the PET technologist will obtain a brief medical history. Let the radiologist or technologist know if you have questions.

You will be asked to change into a patient gown. Your blood Glucose level will be measured. Then, an intravenous injection will be given to you while you are lying down. You will have a small amount of radioactivity in your body when you leave the facility.

After the injection, you will need to lie still and relaxed, without talking, for 30 to 45 minutes. This will allow time for any abnormal tissue to absorb the glucose radiopharmaceutical.

The technologist will then help you onto the examination table. The exam table will gently move into the opening of the scanner and will move through various automated positions over a period of about 45 minutes. You should feel nothing unusual during your exam. You will hear a whirring sound as the scanner operates, and you will be moved slightly after each section. It is important that you remain relaxed and still during the exam so the images do not blur. The technologist will speak to you through a two-way intercom system. You will be able to talk to the technologist if you need assistance at any time during the exam.

May I eat or drink before my scan?
Typically, you will be asked not to eat anything 6 hours before the scan (unless you are diabetic and on insulin). Drink plenty of water before, during and after the exam as well as the day of the exam until you arrive for your appointment. After the exam, please continue to drink water.

It is important to follow these specific instructions. When we call to confirm your appointment, our staff will go over the prep with you and answer any of your questions.

Is the PET/CT scan safe?
Yes, the glucose tracer is short-lived and out of your system very quickly. The radiation exposure is similar to conventional imaging. If your doctor orders additional diagnostic CT scans with IV and oral contrast, we will want to get additional information from you regarding allergies to iodine contrast or kidney problems, etc.

What should I do to prepare?
Allow yourself plenty of time to arrive for your appointment. If you are relaxed and not in a rush, the image quality can actually be better due to less glucose uptake in the muscle.

• Avoid anything with caffeine, sugar, and alcohol for 24 hours prior to the exam and avoid any strenuous exercise.
• Please DO NOT eat or drink anything (except water) beginning 6 hours before your appointment (unless diabetic and on insulin).
• If you are diabetic, please adhere to your normal regimen to try to ensure a normal blood sugar range. A high blood glucose level will decrease the accuracy of the PET/CT scan.
• DO drink plenty of water before, up to, and after your scan unless restricted by your doctor.
• Unless instructed otherwise, take your normally prescribed medication the day of the scan.
• Wear loose, comfortable clothing with no metal.
• Tell your doctor and the PET/CT technologist if you are diabetic, pregnant, or think you might be pregnant.
• It is very important to follow the PET/CT preparation to obtain the most accurate results for you and your physician.  Our office will call to confirm your appointment and can answer any questions you may have.  We will also provide you with any specific information which may be required for your exam.

A PET/CT visit normally lasts about one-and-a-half hours. After you check in at our reception desk, you will be accompanied to a changing room where you will put on an examination gown. The next step involves an injection of the special radioactive isotope and glucose. It is a very low dose that passes out of your body within a day. The injected compound moves through the blood stream to cells engaged in metabolizing glucose. Cancer cells and certain other cells are more active in metabolizing glucose than muscles at rest. As a result, the radioactive isotope acts as a space marker for these cells in the PET scanner. Once scanned, the system computer creates a metabolic map of the body and produces an image like the center image above.

We need to allow about 30 minutes for the injection to go to work. During this time, we provide a comfortable lounge chair in a semi-private waiting room. It's a place to sit quietly, relax, and wait for your PET/CT scan to begin.
 
After your rest, you will be shown to the examination suite where you will recline on a couch and take a deeper rest while the PET/CT machine does its important work. 
 
When the scan is complete, you will be shown back to the changing room where you can dress and be on your way. We will examine your pictures carefully and send them to your doctor's office electronically with our detailed report of findings. You will learn about the results during your next appointment with your doctor. 

How will I feel after the scan?
You should feel fine as there are no known side effects from the injected glucose tracer. You can resume normal activity as soon as you are finished with the exam and you may drive yourself home.

When will I receive the results from my scan?
The images will be interpreted by one of our experienced PET/CT radiologists along with a written report communicated to your physician within 48 hours. Your physician will share the results with you.