Auger Emitter Based Radiotherapy- A Possible New Treatment for Cancer

Cancer is a major cause of mortality worldwide (1). A large fraction of cancer patients undergo external radiotherapy, delivering a lethal dose of radiation to the patient’s tumour(s). The main problem with this approach is the collateral damage caused to healthy, surrounding tissue and the side effects, which result. Auger emitters decay by internal conversion (IC) or electron capture (EC) producing a number of Auger cascade electrons (5-8 electrons per decay). These electrons are so low in energy that their range in tissue is in the order of nm-μm. Due to this short range Auger emitters may be able to kill only the target cell while sparing the surrounding healthy tissue. In addition due to the multiple electrons released during the decay these emitters are more likely to produce at cluster of complex DNA damage which are considered to be much more harmful to the cell than dispersed DNA damage produced by Low-LET radiation used in current radiotherapy (2-3) Considerable efforts have been made in the past twenty years to develop Auger emitter-based radiotherapy However, previous studies lack precise measurement of RBE, which is the fundamental factor defining the relationship between local radiation dose and biological damage done for the given Auger emitter, thereby brought the development to a halt. We believe we have the techniques to quantify the biological damage done for a given Auger emitter and thereby pushing the development of Auger emitterbased radiotherapy into reality (4-10).