Molecular imaging

What is molecular imaging?

Molecular imaging is a specialised imaging technique that uses small amounts of radioactive tracers to capture how your body is functioning at a cellular level. This advanced technology allows doctors to detect changes that may not yet be visible on other scans, helping to diagnose a range of conditions quickly and accurately. In addition to imaging, certain procedures can also be used to deliver targeted treatments, offering both diagnostic and therapeutic benefits.

How it works

Molecular imaging uses a small amount of radioactive tracer, or radiopharmaceutical, that targets specific cells or tissues. Special cameras detect the rays emitted by the tracer, producing detailed images that highlight abnormal cell activity.

What to expect

Preparation - Some scans require fasting or special diets, which will be explained when you schedule your appointment
During the scan - A specialist will explain the procedure and administer the tracer. The scan is painless except for a small injection
Time commitment - Depending on the type of scan, it may take 30 minutes, a few hours (with breaks), or multiple short visits across several days
After the scan - Most tracers leave your body naturally within 24-48 hours. You can usually resume your normal activities straight away.

PET/CT: A key molecular imaging tool

One of the most common procedures we perform is the PET/CT scan, which combines positron emission tomography (PET) with computed tomography (CT). Using radioactive tracers, PET/CT highlights areas of high metabolic activity, often associated with cancer.

PET/CT scans are used to:

Detect tumours and metastases
Guide treatment planning (including theranostics and radiation therapy)
Monitor the effectiveness of cancer therapies
Detect cancer recurrence

Learn more about PET/CT

Types of PET/CT scans

See below for the list of PET/CT scans we offer and what each one is designed to assess, so you can feel informed and prepared before your appointment.

PET/CT FDG - Oncology
This PET/CT FDG scan is tailored for cancer assessment. It helps detect tumours, determine their activity, assess treatment response and identify recurrence.
PET/CT FDG - Brain
A PET/CT FDG brain scan shows how the brain uses glucose, helping identify areas of reduced or increased activity. It's commonly used to assess dementia, epilepsy, movement disorders and some tumours, often alongside MRI for a fuller picture of brain function.
PET/CT FDG - Cardiac sarcoidosis
A PET/CT FDG cardiac sarcoidosis scan looks for inflammation in the heart caused by sarcoidosis. It helps guide diagnosis and monitor response to treatment.
PET/CT PSMA - Prostate cancer
A PET/CT PSMA scan uses a tracer that binds to prostate-specific membrane antigen (PSMA). It helps detect prostate cancer and shows whether it has spread to lymph nodes, bones or other areas.

Other types of molecular imaging scans

See below for the list of molecular imaging scans we offer and what each one is designed to assess, so you can feel informed and prepared before your appointment.

A bone scan highlights changes in bone metabolism. It can detect fractures, arthritis, infection or cancer that has spread to the bone—often earlier than other imaging tests.
A cerebral SPECT/CT scan shows blood flow in the brain, combined with CT for accurate localisation. It helps assess seizures, stroke, dementia and head injury.
A DMSA renal scan provides detailed images of kidney structure and function. It is commonly used to assess scarring, congenital abnormalities or reduced function in one or both kidneys.
A gallium scan detects inflammation, infection or certain cancers by tracking how gallium accumulates in the body. It is often used when the cause of a fever or infection is unclear.
A HIDA scan evaluates the liver, gallbladder, bile ducts and small bowel. It helps diagnose gallbladder inflammation, bile duct blockages or abnormal bile flow.
A MAG3 renal scan assesses kidney function and drainage. It helps diagnose blockages, evaluate blood flow and measure how each kidney contributes overall.
A MUGA scan measures how well the heart pumps blood. It provides an accurate left ventricular ejection fraction (LVEF) and is often used before and during certain chemotherapy treatments.
A parathyroid scan helps locate overactive parathyroid glands, which can cause high calcium levels in the blood.
A sentinel node scan identifies the first lymph node (or nodes) that drain a tumour. This helps determine whether cancer has spread while avoiding unnecessary removal of additional nodes.
A sestamibi renal scan evaluates blood flow and function in transplanted kidneys, helping detect rejection or other complications.
A thyroid uptake and scan measures how the thyroid absorbs iodine and maps its activity. It helps diagnose hyperthyroidism, hypothyroidism, nodules and other thyroid conditions.

Safety and special considerations

Molecular imaging is not generally recommended during pregnancy. If you are pregnant or breastfeeding, please inform our staff so we can take precautions.
Breastfeeding mothers may need to express and discard breast milk for 24-48 hours after some scans.
You may need to avoid close contact with pregnant women and young children (under 5 years old) for 24 hours after your scan.

Frequently asked questions

Yes. The radioactive tracers used in molecular imaging involve very low levels of radiation, similar to or less than many other imaging tests. The tracers lose their radioactivity quickly and are eliminated naturally by the body. Most tracers have a short half-life and return to low levels within 24 hours.
Therapeutic nuclear medicine (and theranostics) uses higher doses but are carefully targeted to minimise side effects.
You may be asked to avoid close contact with pregnant women or babies for a short period as a precaution.
Please do not hesitate to contact us if you have any concerns.
Most scans involve a small injection, similar to a blood test. The scan itself is painless.
Side effects from diagnostic scans are extremely rare. You can usually drive yourself home afterwards.
Therapeutic nuclear medicine (and theranostic treatments) may have side effects depending on the type of treatment, this will be discussed with the treating clinician.
Molecular imaging can detect:
- Cancer and how it spreads
- Heart disease and blood flow problems
- Bone disorders, including fractures and metastases
- Thyroid, lung, kidney, and brain conditions
- Many other organ abnormalities
These scans are often combined with CT or MRI to provide detailed information.
- Your images are reviewed by a nuclear medicine specialist
- A detailed report is sent to your doctor
- Digital images are stored securely for future reference.
A specialised team, including nuclear medicine specialists, nurses, and doctors, performs the scan and ensures your safety throughout.
Some scans take as little as 30 minutes, while others may require several visits in one day or consecutive days. You’ll be advised of the exact duration when you book.
Costs vary depending on the scan, although most will meet Medicare eligibility criteria and minimise out-of-pocket cost. Our team will discuss any expenses with you before your appointment.