FMISO

FMISO

Mechanism of FMISO accumulation in hypoxic tissues

FMISO (Fluoromisonidazole) is a radiopharmaceutical used in positron emission tomography (PET) imaging to detect hypoxia in tissues. Hypoxia, a condition characterized by low oxygen levels, is a common feature of many tumors and can influence the effectiveness of radiotherapy and chemotherapy.

Chemical Structure

FMISO is a nitroimidazole compound labeled with the radioactive isotope fluorine-18. The chemical structure of FMISO allows it to selectively accumulate in hypoxic cells, making it a valuable tool for imaging and assessing tumor hypoxia.

Mechanism of Action

FMISO is taken up by cells and undergoes a series of reduction reactions. In the presence of normal oxygen levels, FMISO is re-oxidized and diffuses out of the cell. However, in hypoxic conditions, FMISO is reduced to reactive intermediates that bind to intracellular macromolecules, leading to its accumulation in hypoxic tissues. This property allows FMISO to serve as a marker for hypoxia in PET imaging.

Clinical Applications

FMISO PET imaging is used in the evaluation of various cancers, including head and neck cancer, lung cancer, and glioblastoma. By identifying hypoxic regions within tumors, FMISO imaging can help in planning treatment strategies and assessing the prognosis of cancer patients.

Advantages and Limitations

FMISO offers several advantages in hypoxia imaging, including its specificity for hypoxic tissues and the ability to provide quantitative data on oxygenation levels. However, its use is limited by the need for specialized PET imaging facilities and the short half-life of fluorine-18, which requires rapid synthesis and imaging.

Related Pages

• Positron emission tomography
• Hypoxia (medical)
• Radiopharmaceutical
• Tumor
• Radiotherapy