Dose response curves for the induction of DNA DSBs after58Fe ion irradiation in human M059K andM059J cells. Results earlier generated  with X-rays are depicted as gray symbols for comparison; theyare similar to results generated in parallel to the 58Feirradiations but for limited number of doses in the range of interest(not shown). (A) Human M059K cells were embedded in agaroseblocks and were exposed to different doses of 1 GeV accelerated58Fe ions. Induction of DSBs was assayed by asymmetricfield inversion gel electrophoresis (AFIGE), a pulsed-field gelelectrophoresis method. Irradiated agarose blocks were processedimmediately after irradiation using either HTL or LTL. Gels were scannedin a Fluor Imager and the fraction of DNA released from the wells intothe lane (FDR) was determined for different radiation doses. Datarepresent the calculated average and standard deviation from 4determinations (agarose blocks) in one experiment. (B) M059Jcells embedded in agarose blocks were irradiated and analyzed asdescribed above. Data represent the calculated average and standarddeviation from 4 determinations in one experiment.