APTAMER LABELED WITH F-19 NUCLEUS FOR TARGETED MOLECULAR IMAGING BY MRI

摘要

Magnetic Resonance Imaging, usually based on 1H as the magnetic nucleus, is an important diagnostic technique that is commonly used in hospitals for the diagnosis of disease. MRI allows for the non- invasive imaging of soft tissue with a superb spatial resolution. Magnetic Resonance Imaging based on 19F instead of 1H opens up new diagnostic possibilities. The 19F nucleus has a high gyromagnetic ratio (40 MHz/T) and a natural isotopic abundance ratio of 100%. In the human body, 19F containing structures are exclusively present in the form of solid salts in e.g. teeth and bones. As a consequence, the J2 relaxation times of the endogenous 19F atoms are extremely short and the MR signal is hardly detectable, in other words, the lack of endogenous,19F-based structures with relatively high transverse relaxation times assures a very low background MR signal. Therefore, exogenous 19F-based MRI contrast agents allow for "hot spot" imaging in a way similar to other techniques such as PET (positron emission tomography). As a useful extension of its diagnostic use, MRI is also proposed for the monitoring of the delivery of bio-active agents such as therapeutic or diagnostic agents. I.e., MRI can not only be used for treatment planning, but also to control local drug delivery under image guidance.