Mark Hill

Everybody is exposed to ionising radiation throughout his or her lives, either from natural sources, most notably radon gas, or artificial sources, such as medical exposures. Ionising radiation can cause malignant diseases in people exposed to it and inherited defects in later generations. However, exposure to radiation can also be beneficial and is widely used in medicine for both diagnosis (diagnostic radiology and nuclear medicine) and in the treatment of cancer (radiotherapy). Increased understanding of the mechanisms of radiation damage and response is important, not only to improve the assessment of the risk associated with exposure but also in optimising cancer treatment. Additionally the benefit of any medical examination using ionizing radiation has to be weighed up against the inherent risk associated with an exposure. Exposure to ionising radiation produces a great diversity of chemical, biochemical, cellular, tissue and whole body responses. The subsequent response not only depends on the amount of energy deposited by radiation but on the pattern of energy deposition along individual radiation tracks along with the temporal and spatial distribution of these tracks. The main emphasis of the research is to assess and formulate mechanisms linking the temporal and spatial pattern of energy deposition events on the scale of DNA, cells and tissues to subsequent biological response (including DNA damage and repair, chromosome, aberration formation, cell death, transformation, genomic instability and cellular signalling). This is then interpreted in the context of risk associated with low level exposures or radiotherapy where new treatment procedures such as the use of proton or ion therapy or radio-labelled ligands rely on the track structure properties of these radiations to lead to therapeutic gain (killing the cancer cells while minimising damage in normal tissues).   Schematic of alpha-particle track interacting with DNA, producing clustered damage       Localization of repair proteins (RAD51) to damage in a cell nucleus following alpha-particle traversal       The group facilitates radiation work across the Institute by providing a range of radiation resources and expertise. Irradiation facilities include high and low dose rate gamma-rays, pulsed linac, diagnostic and orthovoltage x-rays, a range of monoenergetic ultrasoft x-rays and an alpha-particle irradiator.

Appointments 2008 Head of Radiation Biophysics, Gray Institute for Radiation Oncology & Biology, University of Oxford 2001 - 2008 Head of Biophysics Group, MRC Radiation & Genome Stability Unit, 2002 Visiting Fellow at Reading University 1995 - 2001 Non clinical post-doctoral scientist, MRC Radiation & Genome Stability Unit 1994 - 1995 Non clinical post-doctoral scientist, MRC Radiobiology Unit 1991 - 1994 Post doctoral research assistant, Dept. of Physics, Queen Mary & Westfield College, University of London