Molecular imaging

The 3 possible steps used in most molecular imaging procedures are:

• giving you a small amount of a radiotracer (also known as a radiopharmaceutical)
• scanning your body with a special, very sensitive camera that shows where the radioactivity is in your body — you may have one or more scan appointments
• sometimes rotating the camera around your body and combining it with a CT scan to get a more detailed image (called a SPECT-CT scan).

CT scan

The radiotracer is usually injected into a vein. It enters the blood and travels to the area of your body being examined. For some scans it is swallowed, inhaled or injected into the tissue beneath the skin.

Molecular imaging is used to help diagnose many conditions, including:

• musculoskeletal injuries and pain
• cancers
• problems with heart and kidney function
• thyroid, parathyroid and brain disorders
• problems with the lungs, stomach, liver, gallbladder and bowel
• other abnormalities in the body.

Molecular imaging can also be used to show if there has been improvement or worsening of a condition or abnormality you have been having treatment for.

After the radiotracer is given, the scan may begin immediately or there may be a wait while the radiotracer gets to the part of your body being examined. If the wait is more than an hour, you can leave the department and come back at an agreed time.

For the scan, you will lie on a bed. The camera is positioned close to the area being examined. The camera picks up signals from the radiotracer inside your body — but this takes time, so it is important to keep very still so the images are clear.

If a SPECT-CT scan is needed you may need to remove some clothing and any metal objects.

SPECT-CT increases the accuracy and provides more detail of the abnormalities and location.

Your appointment letter will tell you approximately how long your scan will take.

When you get your appointment, you will be given a time and instructions on what to do to prepare for your scan.

You may be asked to confirm what medications and supplements you are taking. Some scans may need you to make dietary and medication changes. 

Tell your healthcare provider if you:

• are pregnant or may be pregnant
• are breastfeeding
• have had difficultly before with intravenous (IV) access during medical procedures.

• The radiotracer used will quickly leave your body over the next 24 hours, mostly through your wee (urine).
• Drinking plenty of fluids will help you to flush the radiotracer out of your body for some scans.
• Adults may be advised to limit continuous close contact with young children and pregnant women until the next day. These precautions depend on the scan you have.
• If you are breastfeeding you may be advised to not breastfeed for a period of time, then discard any breastmilk before starting again.
• You can get back to your usual activities and eating straight after the scan.
• It is safe to share a bed with your partner on the night of the scan, unless you are told not to.
• There are no restrictions for handling pets.

A molecular imaging specialist will view the images and write a report about what your scan shows. The report will be sent to the healthcare provider who asked for the test.

Your healthcare provider will discuss the test results with you at a follow-up appointment, over the phone or by email or text message.

Molecular imaging is a very safe test.

Allergic reactions to the radiotracer are possible but extremely rare. Most people do not feel any effects from the radiotracer at all. Sometimes, an extra medication may be given as part of the scan.

The radiotracer is designed to show what is happening inside your body. It helps us see, but it does not change anything in your body.

Every precaution is taken to ensure that your exposure to radiation is:

• low — only small amounts are used for diagnosis
• short — the radiotracers used in diagnostic tests leave the body quickly
• carefully controlled — the facilities, equipment and materials meet strict safety standards.

If you are pregnant or think you might be pregnant, or are breastfeeding, you should tell your healthcare provider. They will let you know if you need to take any precautions, delay the scan or have a different test instead.

You will need to be referred for a molecular imaging procedure by your healthcare provider. You cannot refer yourself.

Depending on why imaging is needed, this procedure can be done for free in the public health system, if you meet the criteria. You also have the option of paying for it through a private imaging provider.