National Synchrotron Light Source Symposium

The concept of Photon Activation Therapy (PAT) as a cancer treatment was developed by the late Ralph G. Fairchild et al. at BNL in the early 1980’s. The Translational Radiotherapy Research Group at Ben Gurion University carries out studies relevant to PAT, both in vivo and in vitro, that validate its potential to increase the effective radiation dose to malignant tumors while sparing surrounding normal tissues. In our studies, PAT exploits the emission of low energy, short range Auger electrons from a platinum (Pt) atom, complexed to tumor cell DNA, to split the DNA into fragments rendering its repair enzymes incapable of recognizing the template. Auger electron emission is achieved by inducing a photoelectric effect in the Pt using monoenergetic photons whose energies lie at, or slightly above, the K or L absorption edge of the Pt/DNA complex. The vehicle responsible for transporting and binding Pt to tumor cell DNA is a porphyrin molecule (PtTMPyP4). The K and L absorption edges of Pt are activated by synchrotron radiation or 103 Pd brachytherapy seeds, respectively. An aim of this seminar is to demonstrate the versatility of synchrotron radiation with respect to medical and biological mechanisms. It will address issues pertinent to the implementation of successful PAT such as the ability of porphyrin molecules to transport and bind high Z atoms to tumor cell DNA; the use of medical beam lines at synchrotron facilities to provide monoenergetic photons and elicit Auger emission; the potential application of synchrotron radiation to identify intracellular mechanisms of molecular transport (X-ray miocroscopy and Infra-red spectroscopy); and the demonstration of the clinical potential of PAT as a treatment for prostate, breast, head and neck, and brain tumors.