Rx 650

X-rays: Cells were plated in T25 flasks 24 h before irradiation and subsequently irradiated with X-rays, which were generated using an X-ray machine (FAXITRON RX-650, Faxitron Bioptics, LLC, Tucson, AZ, USA) operated at 50 kVp. The dose rate was approximately 0.5 Gy/min. All of the irradiations were carried out at room temperature.
Carbon ions: Most of the irradiations were performed with a carbon ion beam of 165 MeV/u in the heavy ion therapy terminal of the Heavy Ion Research Facility in Lanzhou (HIRFL) at the Institute of Modern Physics (IMP), Chinese Academy of Sciences. Some experiments were conducted with a carbon ion beam of 290 MeV/u in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), Japan. Asynchronously growing cells were seeded in T25 flasks 24 h prior to exposure to carbon ions. The dose-averaged LET of the carbon ion beams on the cell samples was adjusted to 13, 30 or 75 keV/μm according to our experimental requirements. All of the irradiations were carried out at room temperature, and the control groups were sham-irradiated.

The cells were irradiated with 200 kV X-ray via RX-650 (Faxitron Bioptics, Tucson, AZ, USA) at a dose rate of 0.7 Gy/min without a filter under both normoxic and hypoxic conditions in the hypoxic chamber described below.

Human renal carcinoma 786-O cells were cultured in RPMI-1640 media (GIBCO, NY, USA) supplemented with 10% fetal bovine serum (Hyclone, MA, USA) at 37°C and 5% CO₂. Irradiation was carried out by laboratory X-ray source (RX-650, Faxitron Bioptics, USA) [27 (link)]. The dose rate was 0.8 Gy/min (100 keV, 5 mA). Cells were seeded into 12-well plates and grown to <70% confluence at the time of irradiation.

Cells were irradiated with X-rays, which were generated from an X-ray machine (FAXITRON RX-650, Faxitron Bioptics, LLC., Tucson, USA) operated at 50 kVp energy. The dose rate during irradiation was about 0.5 Gy/min. All irradiations were performed at room temperature.