PET scanning, or positron emission tomography, has shown potential for diagnosing patients with dementia, which is currently challenging.PET scanning is a medical imaging instrument that is able to detect metabolic changes in the body. It works by detecting gamma rays that are given off by a radioactive molecule or substance which the patient will have been given. Dependent on what the scan is for, you can get different tracer molecules to detect different metabolic processes. The most common, typically used for cancers, is fluorodeoxyglucose because it monitors glucose uptake which is altered in cancers.
Many patients living with dementia may not have a diagnosis due to the variety and severity of the different diseases that cause dementia. The range of technology available in different NHS trusts around the country can also hinder diagnoses. PET scanning may be the answer. Many of the metabolic processes altered in common types of dementia are known and therefore PET markers have been developed that can distinguish between normal brain and abnormal brain metabolic processes. For example, the most common disease causing dementia, Alzheimer’s disease (around 60-70% of dementia) is associated with decreased brain activity and therefore lower metabolism of sugar. In these cases the fluorodeoxyglucose ‘marker’ can be utilised to assess the patient.
Our understanding of the types of dementia is advancing and with it comes new treatment opportunities. However, in the majority of dementia the disease process has been happening for many years before patients may even notice they have anything wrong. This is a huge obstacle for drug development, as reversing severe brain damage, not resulting from dementia, is extremely difficult, rarely successful and impossible to completely reverse and dementia has an additional level of complexity. However, using PET to diagnose people earlier and monitor their disease progress you could not only provide tailored management for these patients but could also lead to a deeper understanding of disease progression. This additional knowledge and patient contact could accelerate drug development and clinical trial participation. However, PET scans are very expensive and other scans may provide a similar understanding at a fraction of a cost.