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Nuclear medicine for better diagnosis and treatment of Alzheimer's
Alzheimer's is the most common form of dementia and is relatively prevalent, especially in the elderly. However, both the causes of the disease and the underlying mechanisms remain relatively unclear. New nuclear medical imaging methods could make a significant contribution to solving this problem, reports the German Society for Nuclear Medicine.
The neurodegenerative diseases will be a main topic at the joint annual meeting of the German, Austrian and Swiss Nuclear Medicine Societies at the end of April in Dresden. Because new nuclear medicine methods of molecular imaging can help to "objectively record the changes in the brain and thus better understand the development of these diseases and hopefully treat them successfully in a next step," according to the DGN.
The protein deposits in the brains of Alzheimer's patients can be visualized with the help of nuclear medicine, which can also contribute to a better understanding of the causes of disease and the development of new therapeutic approaches. (Image: Juan Gärtner / fotolia.com) Neurodegenerative diseases particularly feared
Dementia is a particularly dreaded complaint given the associated decline in mental abilities and loss of personality traits. They are among the so-called neurodegenerative diseases such as Parkinson's disease, with Parkinson's speech but mainly in neurodegenerative movement disorders, while dementia mainly affects the cognitive abilities.
Difficulties in diagnosis and therapy
Both complaints (Parkinson's and dementia) "are neurodegenerative diseases, more specifically those that lead to loss of function and nerve cell failure," explains the DGN. At the same time, these diseases are particularly difficult to diagnose and treat, which is partly because neurodegenerative diseases begin to spread in the brain many years to decades before the first tangible symptoms. However, by compensating mechanisms, the brain is able to absorb the failures to a certain extent and therefore the process goes unnoticed for a long time, explains the DGN. Correspondingly late often a diagnosis is made.
Detect changes in the brain and better understand the causes of the disease
Even after the onset of the first symptoms, a reliable diagnosis of the cause of the disease is often impossible, "because their appearance varies and thus no reliable conclusions on the underlying changes in the brain allows," said the DGN. "New nuclear medicine methods of molecular imaging can now help to objectively record the changes in the brain and thus better understand the development of these diseases and, hopefully, treat them successfully in a next step," reports the association.
Protein deposits in the brain are critically important
So far, a reliable detection of diseased protein deposits in the brain was only possible through the analysis of brain tissue under the microscope, so that a reliable diagnosis of the disease was excluded during the lifetime of the patient, reports the DGN. Two forms of abnormal protein deposits in the brain are considered typical of Alzheimer's disease: the so-called amyloid plaques in the intercellular space of the brain and other deposits of the so-called tau protein (neurofibrils or "tangles") in the Nervenzellen.Welche effect, the protein deposits have so far not known, but it is assumed that they are causally related to the disease, according to the DGN.
Visualization of abnormalities in the brain
The early forms of the glued protein fragments presumably affect the function of the synapses - the nerve transmission sites - and thus of the nerve cells as a whole, reports the DGN. By means of new nuclear-medical, imaging procedures, a visualization of the relevant abnormalities in the brain will become possible even in living people. The successes by means of the so-called positron emission tomography (PET). "In this highly sensitive imaging method, changes in the molecular order of magnitude are made visible in humans through the use of so-called tracers - low-radioactivity-labeled trace substances", explain the experts.
So-called tracers make the protein deposits visible
First of all, to prepare the PET, the patient is injected with a small amount of the tracer substance into a brachial vein so that it spreads throughout the body and then specifically connects with the pathological protein deposits in the brain, reports the DGN. The distribution of the tracer in the body can then be "represented by the radioactive radiation emanating from him by means of a special, highly sensitive PET camera." The procedure for the person examined with no pain or other inconvenience.
Basis for the development of new therapeutic approaches
In the meantime, numerous tracers have been developed for neurodegenerative diseases and, for example, they have been able to detect the amyloid deposits in this way for some time, reports the DGN. An Alzheimer's disease could thus be detected or excluded very early, the latter plays an important role especially in patients with mild impairment of their mental capacity. Likewise, the process of amyloid imaging is of great importance with regard to the development of new therapeutic approaches against Alzheimer's and their subsequent success monitoring. Only recently are also tracers available that allow imaging of tau deposits. However, the tau tracers are currently being tested and are not yet routinely used, according to the DGN. (Fp)