핵의학적 세포증식 영상 (Nuclear Imaging of Cellular Proliferation) |
Author |
여정석, |
Jeong Seok Yeo, M.D. |
Affiliation |
울산대학교 의과대학 서울아산병원 핵의학과 Department of Nuclear Medicine, Asan Medical Center University of Ulsan College of Medicine, Seoul, Korea |
Abstract |
Tumor cell proliferation is considered to be a useful prognostic indicator of tumor aggressiveness and tumor
response to therapy, but in vitro measurement of individual proliferation is complex and tedious work. PET
imaging provides a noninvasive approach to measure tumor growth rate in situ. Early approaches have used
18F-FDG or methionine to monitor proliferation status. These 2 tracers detect changes in glucose and amino acid
metabolism, respectively, and therefore provide only an indirect measure of proliferation status. More recent
studies have focused on DNA synthesis itself as a marker of cell proliferation. Cell lines and tissues with a high
proliferation rate require high rates of DNA synthesis. [11C]Thymidine was the first radiotracer for noninvasive
imaging of tumor proliferation. The short half-life of 11C and rapid metabolism of [11C]thymidine in vivo make the
radiotracer less suitable for routine use. Halogenated thymidine analogs such as 5-iodo-2-deoxyuridine (IUdR) can
be successfully used as cell proliferation markers for in vitro studies because these compounds are rapidly
incorporated into newly synthesized DNA. IUdR has been evaluated as a potential in vivo tracer in nuclear
medicine, but the image quality and the calculation of proliferation rates are impaired by its rapid in vivo
degradation. Hence, the thymidine analog 3'-deoxy-3'-18F-fluorothymidine (FLT) was recently introduced as a stable
proliferation marker with a suitable nuclide half-life and stable in vivo. [18F]FLT is phosphorylated to
3-fluorothymidine monophosphate by thymidine kinase 1 and reflects thymidine kinase 1 activity in proliferating
cell. [18F]FLT PET is feasible in clincal use and well correlates with cellular proliferation. Choline is a precursor for
the biosynthesis of phospholipids (in particular, phosphatidylcholine), which is the essential component of all
eukaryotic cell membranes and [11C]choline, which is a new marker for cellular proliferation. (Korean J Nucl Med 38(2):198-204, 2004) |
Keyword |
Cell proliferation, PET, Nucleoside, FLT, Choline |
Full text Article |
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