Abstract
We confirmed the effect of ion recombination using a parallel-plate ionization chamber: dose monitor for clinical use and the Advanced Markus chamber. A 290 MeV/u carbon-ion beam was irradiated using the continuous spot-scanning method in a field size of 5 cm by 5 cm with 2 mm spacing. We tested three beam intensities (1.35 × 108, 2.69 × 109, and 4.03 × 109 particle per second (pps)) at two linear energy transfers (12 keV/μm and 200 keV/μm). The charge (Q) was measured by changing the voltage of the Advanced Markus chamber and that of the dose monitor. Then, Boag’s method was used to calculate the saturated charge (Qsat). For the Advanced Markus chamber, 300 V is a sufficient potential to collect charge. For the dose monitor, Qsat/Q at 2500 V was 1.024 for 4.03 × 109 pps, indicating that the general recombination correction cannot be ignored when high dose rate treatment is performed using a carbon-ion scanning beam.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have