Abstract

Apoptosis is an organized and fundamental energy dependent cell death process that is triggered by an internal or external signal. The possible triggers include anti-hormonal therapy, immune reaction, radiation exposure, chemotherapy, DNA damage or an abandonment of the growth factor. The process involves a contraction of cytoplasm, protein cleavage, membrane blebbing, cutting of the intracellular components and formation of apoptotic bodies. Normal apoptosis plays key role in homeostasis, regulation of the immune system, embryogenesis, hormone dependent atrophy and normal cell turnover. However, any abnormalities in the process of cell death can be a factor in many medical conditions including neurodegenerative disease, cancer development, viral or toxin induced hepatitis, bone marrow or organ transplant rejection, HIV, diabetes, or cardiovascular disease. Moreover many anti-cancer and therapeutic drugs are designed on the basis of the apoptotic cell death mechanism, and their efficiency can be estimated by monitoring the ongoing apoptosis rate in the targeted organ. Hence, molecular imaging of apoptosis using single positron emission computed tomography or positron emission tomography can offer an early detection of disease, monitoring the staging of disease, an assessment of efficacy of the treatment process and the development of novel drugs to initiate or inhibit apoptosis