A tabletop micro X-ray beam irradiation system has been developed to research biological radiation effects on living cells. The micro beam system is composed of a micro focus X-ray tube, a capillary for X-ray guide, an inverted microscope and others.A beam profile was measured by the knife-edge method and the focused beam size was proved to be 12μm in diameter. The micro dosimetric characteristics of the single cell irradiation was investigated by a photon-electron transport simulation.The maximum dose rate for a targeting cell was estimated to be 0.05Gy/s.
In a preliminary experiment, a normal human fibroblasts cell grown on a radiophotoluminescent glass plate was irradiated by the microbeam. After the irradiation, the targeting cell was stained with anti-γ-H2AX antibody to visualize the effects on DNA double strand breaks.In fluorescence microscopy, foci in the nucleus corresponding to the radiation damage and the X-ray beam spot were simultaneously observed at the position of the targeting cell.
