These services are available to patients at our Clinical and Research Imaging Centre (CRIC) within SAHMRI and our Southern Specialist Centre.

Two distinct PET/CT examinations are available for the assessment of dementia – an FDG Brain PET/CT, which evaluates how the brain is functioning, and an Amyloid PET/CT, which detects the abnormal protein deposits associated with Alzheimer’s disease. Both scans provide complementary information and may be requested by your neurologist, geriatrician, or specialist physician to support diagnosis and guide management.

Who May Benefit From These Scans?

These scans are particularly relevant for patients presenting with:

• Progressive memory loss or cognitive decline
• Suspected early-onset Alzheimer’s disease
• Atypical or diagnostically uncertain dementia presentations
• Distinguishing Alzheimer’s disease from other neurodegenerative conditions such as frontotemporal dementia or Lewy body dementia
• Assessment prior to commencing disease-modifying therapy

FDG Brain PET/CT

An FDG (fluorodeoxyglucose) brain PET/CT evaluates cerebral metabolic activity – in other words, how well different regions of the brain are working. It is a well-established tool in the diagnostic workup of Alzheimer’s disease and other dementias, providing functional information that complements structural imaging such as MRI.

How It Works

The brain is one of the most metabolically active organs in the body, consuming large amounts of glucose to sustain normal function. The FDG tracer – a radioactive form of glucose – is taken up by active brain cells in proportion to their metabolic activity.

In Alzheimer’s disease and related conditions, characteristic regions of the brain show reduced metabolic activity, reflecting neuronal dysfunction or loss. These patterns of reduced uptake are highly specific and allow the Nuclear Medicine Physician to differentiate between types of dementia and to identify changes consistent with early neurodegeneration – often before structural changes are visible on MRI.

What to Expect

The FDG brain PET/CT requires a period of quiet rest before and during tracer uptake, to ensure the brain is in a neutral, resting state for consistent and accurate imaging. On arrival, a cannula (plastic tube) is placed in a vein in your arm and a blood glucose reading is taken.

You will be settled into a quiet, dimly lit room. It is important that you rest with your eyes open for approximately 40 minutes – this minimises visual and cognitive stimulation so that the tracer distributes evenly across the brain. The FDG injection is administered during this rest period.

Following the uptake period, a brain scan is performed. This typically takes around 15 minutes. You may remain fully clothed, with only large metal items removed.

Scan Preparation

• 6-hour fast from all food and fluids prior to your appointment (water is permitted).
• 500 mL of plain, unflavoured water in the hour leading up to your appointment.
• No strenuous activity or exercise for 24 hours prior.
• Wear comfortable clothing and avoid jewellery or large metal items.
• Diabetic patients – please contact our team prior to your appointment for specific preparation instructions.
• Please advise our team if you will require a carer or support person to accompany you.

Amyloid PET/CT – 18F-Florbetaben (FBB)

Amyloid PET/CT is a specialised brain imaging examination that detects the presence and distribution of amyloid-beta plaques in the brain – one of the hallmark pathological features of Alzheimer’s disease. It uses the radiotracer 18F-florbetaben (FBB), which binds directly to amyloid deposits, making them visible on the PET scan.

This scan provides diagnostic information that is not available through any other non-invasive imaging technique and can meaningfully change clinical management – particularly in cases where the diagnosis is uncertain or where early intervention is being considered.

How It Works

In Alzheimer’s disease, abnormal proteins – primarily amyloid-beta – accumulate in the brain years, and sometimes decades, before symptoms become apparent. The 18F-florbetaben tracer binds selectively to these amyloid plaques, producing a PET signal that allows the Nuclear Medicine Physician to determine whether amyloid pathology is present and how extensively it has spread across the brain.

A positive amyloid scan – one showing significant amyloid deposition – supports a diagnosis of Alzheimer’s disease. A negative scan effectively excludes amyloid as the cause of cognitive symptoms, helping to direct investigation toward other diagnoses.

Clinical Value

Amyloid PET/CT is particularly useful in the following clinical scenarios:

• Patients with mild cognitive impairment (MCI) where an underlying Alzheimer’s diagnosis would change management
• Atypical or early-onset presentations of dementia where diagnosis remains uncertain after standard workup
• Distinguishing Alzheimer’s disease from non-amyloid dementias
• Assessment of eligibility and treatment response for emerging disease-modifying therapies targeting amyloid deposits

What to Expect

On arrival, a cannula (plastic tube) is placed in your arm, and you will be shown to a private uptake room with a recliner and television. You will be connected to a saline drip, and the Amyloid tracer will be administered. The tracer requires approximately 60-90 minutes to circulate and bind to amyloid deposits in the brain. During this time, you may rest comfortably in your uptake room.

Following the uptake period, a brain scan is performed. This takes approximately 20 minutes. You may remain fully clothed, with only large metal items removed.

Scan Preparation

• No fasting is required for this scan.
• 500 mL of water in the hour leading up to your appointment is recommended.
• Wear comfortable clothing and avoid jewellery or large metal items.
• Please advise our team if you will require a carer or support person to accompany you.

Important – Out-of-Pocket Cost for Amyloid PET/CT

Amyloid PET/CT is not currently covered by Medicare and is not eligible for a Medicare rebate. This means there will be an out-of-pocket cost for this examination. Please contact our SAHMRI clinic directly for current pricing information prior to booking. We recommend discussing the clinical value of this scan with your referring specialist before proceeding, so you can make an informed decision about whether it is right for your circumstances.