The Role of Molecular Structure and its Implications for Electron- and Positron-based Diagnosis and Therapy

Chief Supervisor
Dr. Suzanne Smith, ANSTO
Supervisors
Professor Stephen Buckman (Australian National University)
Dr. James Sullivan (Australian National University)
Centre Nodes
ANSTO
ANU

Standard X-ray therapy and Proton therapy beams work in a similar fashion in treating cancer. Proton therapy beams have an advantage as they can be deposited in tissue or cancer more accurately, and this can result in a significant reduction in dose to neighbouring healthy tissue. There is also a reduction in the side effects and in the potential for recurrence of cancer. Like X-ray beams, energized particles, such as protons, electrons or positrons, pass near an orbiting electron in an atom or molecule, and can eject the electron from its orbit. This ionization process changes the character of the atom or molecule in which it resides. However, like the interaction of high-energy radiation (α, β, γ, or heavy ions) with living cells, this does not always lead directly to DNA strand breaks.

This project will investigate the effect of molecular structure on the potential damage to DNA by electron interactions. It will also study the role of the molecular structure of the carrier molecules used in the delivery of radioactive positron emitters for PET imaging. It will involve the use, or synthesis, of a range of biomolecules for investigation by electron and positron impact spectroscopy. The goal is to enhance the effectiveness of the various beam therapies through an understanding of the fundamental processes, and to gain a thorough understanding of the processes which underpin the application of PET radiopharmaceuticals for diagnosis and therapy of cancer.

The project is a collaboration between the ANU and ANSTO. The student will need to be willing to travel between ANSTO, Sydney and ANU, Canberra. The student will be expected to work within a diverse team of chemists, radiochemists, physicists, mathematicians and biologists. They will need to have an interest in physics and or chemistry, radiation therapy and a willingness to handle radioactive materials in a safe and professional environment.

Selected reading:

www.proton-therapy.org/howit.htm

PET Imaging of dose distribution in proton-beam cancer therapy. Nuclear Technology and Radiation Protection (2005) 20(1), 23-26.

S. Denifl et al, Electron Attachment to 5-Chloro Uracil. J Chem. Physics 118(9) (2003) 4107 - 4114.

F Martin et al, DNA Strand Break Induced by 0-4 eV Electrons: The role of shape resonances. Phys. Rev. Lett. 93(6) (2004) 068101-4

A. M. Scheer et al, Bond Breaking and Temporary Anion States in Uracil and Halouracils: Implications for the DNA Bases. Phys. Rev. Lett. 92(6) (2004) 068102-1-4.

G. Hanel et al, Electron Attachment to Uracil: Effective Destructive at Subexcitation Energies. Phys. Rev. Lett. 90(18) (2003) 188104-1-4.