Visualization of heavy ion tracks by labeling 3'-OH termini of induced DNA strand breaks.

African green monkey kidney cells, CV-1, were irradiated with Carbon ions (LET: 735 keV/µm Argon ions (LET: 3,000 keV/µm) to visualize ion tracks through the cell nucleus by labeling the 3'-OH termini result of DNA strand breaks. The 3'-OH termini of DNA were labeled with BrdU-triphosphate catalyzed by TdT. This method of TUNEL (TdT-mediated dUTP Nick End labeling) is based on the specific binding of TdT to 3'-OH termini of DNA.

A new method for the simultaneous detection of mammalian cells and ion tracks on a surface of CR-39.

The geometric locations of ion traversals in mammalian cells constitute important information in the study of heavy ion-induced biological effects. We employed a contact microscopy technique, which was developed for boron imaging in boron neutron capture therapy to the irradiation mammalian cells by low-energy heavy ions. This method enables the simultaneous visualization of mammalian cells as a relief on a plastic track detector, CR-39, and the etch pits which indicate the positions of ion traversals.

Number of Fe ion traversals through a cell nucleus for mammalian cell inactivation near the bragg peak.

HeLa and CHO-K1 cells were irradiated with Fe ions (1.14 MeV/nucleon) near the Bragg peak to determine how many ion traversals through a cell nucleus are necessary to induce cell inactivation. The ion traversals through a cell nucleus were visualized by immunostaining the phosphorylated histone H2AX (gamma-H2AX), as an indicator of DNA double strand breaks (DSBs), to confirm that DSBs are actually induced along every Fe ion traversal through the nucleus.