Recent advances in apoptosis imaging using radionuclide-labeled tracers

Apoptosis or programmed cell death is an important form of cell death. Apoptosis is involved in numerous human pathological conditions, such as neurodegenerative diseases, ischemic damage, autoimmune disorders, and many types of cancer. Visualization of apoptosis is enormously beneficial in clinical diagnosis, development of new therapies, and therapeutic evaluation. The traditional methods of apoptosis detection include optical microscopy, TdT-mediated-dUTP nick end labeling analysis, and flow cytometry. However, these invasive techniques restrict the conduct of follow-up studies. Apoptosis imaging in living subjects has contributed to nondestructive observation and in understanding the biological process of apoptosis. The developments in PET and SPECT technologies, including the synthesis of targeted radionuclide tracers, led nuclear medicine into a new era of molecular imaging. The development and application of PET and SPECT as apoptosis imaging probes rendered the non-invasive detection of apoptosis in vivo a reality. This article reviewed the recent advances in apoptosis imaging using radionuclide-labeled tracers. Key words: Apoptosis; Molecular probes; Radionuclide imaging; Positron-emission tomography; Tomography, emission-computed, single-photon