Abstract
We examined the DNA double strand break (DSB)/chromosome repair in human cells irradiated with high LET radiation. Normal human fibroblasts (HFLIII) were irradiated with carbon ion, neon ion, and iron ion radiation. After 0, 0.5, 1, 2, 6, 24 hours, the DSB repair process was monitored with the G1-type premature chromosome condensation (PCC) technique. Fluorescence in situ hybridization (FISH) was also performed with the PCC samples (24hours after irradiation). Although cells were exposed to identical LET (70keV/μm) as carbon ions, the repair process of cells irradiated with neon ions was slower than with carbon ions. The remaining number of fragments for neon irradiation was much lower than with iron ions (LET: 200keV/μm). After 24 hours from irradiation with neon ions, cells had almost repaired similar to cells irradiated with X-ray and carbon ions but cells irradiated with iron ions had unrepairable or difficult DSB. FISH assays are ongoing. Our results with G1 PCC indicate that different ions that have equal LET values can imply different repair process.
