Positron Emission Tomography Imaging of Tumor Apoptosis with a Caspase-Sensitive Nano-Aggregation Tracer [ 18 F]C-SNAT.

Cellular apoptosis is an important criterion for evaluating the efficacy of cancer therapies. We have developed a new small molecule probe ([18 F]C-SNAT) for positron emission tomography (PET) imaging of apoptosis. [18 F]C-SNAT, when activated by caspase-3 and glutathione reduction, undergoes intramolecular cyclization followed by self-assembly to form nano-aggregates in apoptotic cells. This unique mechanism creates preferential retention of gamma radiation signals in targeted cells and thus enables the detection of apoptosis using PET, a sensitive and clinically practical technique. This protocol describes the chemical synthesis, radiolabeling and PET imaging of apoptosis using this probe.