The impact of microbeams in radiation biology

Cellular micro-irradiation is now recognised as a powerful technique for understanding how ionising radiation interacts with living cells and tissues. Charged-particle microbeams are uniquely capable of delivering single, or counted multiple particles to selected sub-cellular targets. This capability is particularly useful for studying the risks associated with environmental exposures to alpha -particle emitting isotopes (such as radon) where exposed cells within the body are unlikely to receive more than one particle traversal. Microbeam methods are also seen as highly appropriate for studying the so-called 'bystander effect' (where unirradiated cells respond to signals transmitted by irradiated neighbours). Using the Gray Laboratory microbeam, we have been able to demonstrate a significant increase in the levels of cell death and DNA damage in a population of cells after irradiating just a few cells within a population, Also, by targeting the cell cytoplasm, we have shown that intra-cellular signalling between the cytoplasm and nucleus can cause DNA damage, showing that direct DNA damage is not required to observe radiation induced effect in cells. (C) 2001 Elsevier Science B.V. All rights reserved.