Authors: R. Sharma, A. Sharma
Affilation: University of North Carolina, United States
Pages: 202 - 205
Keywords: hypoxia, nitroimidazole, MRI/PET, nanobullets
2-Nitroimidazole is radiosensitizer and serves as imaging contrast agent by 19F- and 31P MR methods. Despite the success of mesonidazole and SR-4554 compounds, very little is known of its hepato-cytotoxicity if it can be potential hypoxia imaging marker and non-toxic drug. Author established the low oxygen, low energy metabolic ratio and gluconeogenesis in nitroimidazole induced hepatocytes and Kupffer cells leading to apoptosis. Several new nanoparticles of nitroimidazole have emerged: nitroimidazole CI-1010, alginate-, silver- nanobullets as nanoparticles in imaging applications. Emerging 18F/19F double labeling techniques further give hope of MRI/PET imaging by using 18F/19F-FETNIM (erythronitroimidazole). Present art exists: 1. 18F/19F -1[2 fluoro-ethoxy-methyl- or -1[2 fluoro-hydroxymethyl-ethoxy-methyl-2- nitroimidazole can be choice of hypoxia MRI/PET imaging contrast agents. 2. availability of HyoxyprobeTM and KU-2285 has enhanced the sensitivity of hypoxia quantitation. 3. copper labeled diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) selectively bind to hypoxic tumor cells. Cu-ATSM PET can be modality to image tumor hypoxia and contribute to the PET signal. 4. Improved compartment modeling analysis separates tumor tissue time-activity of nanoparticle signal into intravascular and extravascular components. 5. the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI), blood oxygen level dependent (BOLD) and FLOOD T2* imaging, and the measurement of lactate by MR methods serve as hypoxia surrogates and provide the pO2 status of the tumor. The fusion of NMR and PET images generates stereotactic marker template of tissue. In conclusion, nanoparticle enhanced multimodal MRI/PET diagnostic sensitivity serves hypoxia events better.
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