Carbon-ion dose distributions with four beam angles for (a) ungated and (b) gated irradiation. Planning dose distribution and accumulated dose simulations with 1 × PCR, 4 × PCR, and 8 × PCR. In the supine position, the beam angle was set to 20, 70, 110, and 340 degrees. The respiratory cycle was 4.2 sec. Yellow lines demonstrate the CTV (patient no. 7). Green arrows show beam direction. Dose assessment metrics for all 14 cases as a function of the number of rescannings. D95, Dmax, and Dmin for (c) ungated and (d) gated strategies. The homogeneity index (HI) is for (e) ungated and (f) gated strategies.