The aim of JRP SIB06 BioQuaRT was to develop measurement and simulation techniques for determining the physical properties of ionising particle track structure on different length scales, and to investigate at the cellular level how these track structure characteristics correlate with the biological effects of radiation. The relevant length scales range from about 2 nm (diameter of the DNA double helix) to about 10 µm (diameter of the cell nucleus).

The JRP SIB06 BioQuaRT addressed the following objectives:

• Development of micro-calorimeters for the direct measurement of energy transfer (lineal energy) for different particles and energies. These were used to assess whether corrections were needed when obtaining lineal energy spectra obtained from conventional microdosimeters that measure ionisation.

• Further development of measurement techniques for particle track structure at different length scales down to the nanometer range. This allowed us to perform a multi-scale characterisation of the radiation qualities used in therapy and the measurement of relevant radiobiological effects within this JRP SIB06 BioQuaRT

• Investigation of the indirect effects of radiation, which is in addition to the direct ionisation damage caused by the production of reactive molecules close to the DNA. The JRP consortium built a prototype system to determine the spatial distribution of biologically relevant reactive species and the relative yield of their production in different ion beams

• The expertise of the JRP partners and their different simulation tools for micro- and nanometric track structure properties were combined to develop a multi-scale model relating the characteristics of track structure to the biological consequences of radiation interaction.
  

Biological reference data and benchmarks for the multi-scale model were created by performing radiobiological assays in cultured tissue cells to quantify the induction of initial DNA damage as well as late effects such as the misrepair of double strand breaks. Well-characterised single ion microbeams of protons, alpha and ¹²C-ions were used to cover a range of relevant radiation qualities.