Carbon-ion dose distributions with a single beam angle for (a) ungated and (b) gated irradiation. Planning dose distribution and treatment dose simulations with 1 × PCR, 4 × PCR, and 8 × PCR. In the supine position, the beam angle was set to 340 degrees. The respiratory cycle was 4.2 sec. Yellow lines demonstrate the CTV (patient no. 7). Green arrows show beam direction. In Figure 1(a), white arrow shows the dose degradation in the CTV. Dose assessment metrics for all 14 cases as a function of the number of rescannings. Beam angle was 340 degrees. D95, Dmax, and Dmin for (c) ungated and (d) gated strategies. The homogeneity index (HI) is for (e) ungated and (f) gated strategies.