Molecular imaging
The term molecular imaging (English: molecular imaging ) the exploration of physiological processes and the diagnosis of diseases at the molecular level by means of imaging techniques in real-time in vivo are summarized.
With the findings of biochemical research and molecular biology, it is in principle possible to return certain diseases to molecular abnormalities. For example, Alzheimer's disease is attributed to the deposition of ( macro - ) molecular plaque in the brain of the patient. The aim of molecular imaging is to detect this molecular signatures of disease and used for medical diagnosis. Ideally, therefore can diagnose and treat diseases before the onset of the first symptoms. In Alzheimer's disease is the deposition of plaques shows years before the clinical symptoms.
Molecular imaging, as well as the theranostic concept, part of a paradigm shift in the existing health care system, which should lead from the current " health " with features curative measures to a prophylactic, preventive health services. In order for the preservation of health and not their restoration is placed at the center of medical care.
The principle of molecular imaging
A signaling molecule, or a transport molecule, atom or particles (for example, a nanoparticle ) is coupled, which is also connected to a " targeting unit ". The latter can be determined, for example, ligands such as antibodies or fragments thereof, aptamers, single peptide sequences, or oligonucleotides. These ligands are specific molecular markers for certain diseases. After the key - lock principle they bind with very high selectivity at the diseased tissue and result in an enrichment of the bound to them, signaling molecules. The turn can be detected and isolated from the outside by means of imaging techniques.
Imaging molecules
The most advanced and established the molecular imaging with radionuclides. The decay of radioactive isotopes can be used with imaging, scintigraphy, positron emission tomography (PET) or SPECT ( single photon emission computed tomography ) can be detected with high sensitivity and very low doses in the picomolar range ( see main article: Nuclear Medicine ).
The main disadvantages of imaging with radionuclides are, in addition to the high cost of these procedures, especially the radiation exposure for the patient. They prevent these methods can be used, for example routine diagnosis or for permanent monitoring of therapy. For the realization of the concept of molecular imaging is therefore currently working on a variety of other diagnostic procedures. These primarily include magnetic resonance imaging, ultrasonography ( ultrasound imaging by ) and optical methods ( usually by means of fluorescence).
Targeted depending on which imaging molecules, ie to be detected, both cellular structures and functions can be visualized. An example of the functional molecular imaging is the imaging of apoptosis.