## 3 Results
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Modality**} & **Motion** & **Dose in** & **Dose in** & **RMS Homo-** & **GPR** & **GPR** & **Irradiation** \\  & **Pattern** & **ROI1** & **ROI2** & **geneity (\%)** & **3\%/3 mm (\%)** & **3\%/2 mm (\%)** & **Time (s)** \\ \hline Stationary & NA \({}^{\star}\) & 1.00 \(\pm\) 0.04 & 0.10 \(\pm\) 0.01 & 96.3 \(\pm\) 0.2 & 98.1 \(\pm\) 0.6 & 95.2 \(\pm\) 1.0 & 167 \(\pm\) 2 \\ \hline \multirow{4}{*}{Free breathing} & 2 mm-0\% & 0.99 \(\pm\) 0.04 & 0.10 \(\pm\) 0.01 & 95.6 \(\pm\) 0.5 & 96 \(\pm\) 3 & 91 \(\pm\) 4 & 167 \(\pm\) 2 \\  & 6 mm-0\% & 0.99 \(\pm\) 0.04 & 0.11 \(\pm\) 0.01 & 92.6 \(\pm\) 0.7 & 90 \(\pm\) 2 & 83 \(\pm\) 1 & \\  & 12 mm-0\% & 0.99 \(\pm\) 0.04 & 0.14 \(\pm\) 0.02 & 87.9 \(\pm\) 1.2 & 83 \(\pm\) 4 & 68 \(\pm\) 3 & \\  & 20 mm-0\% & 0.94 \(\pm\) 0.03 & 0.22 \(\pm\) 0.03 & 84.1 \(\pm\) 3.1 & 61 \(\pm\) 8 & 49 \(\pm\) 8 & \\ \hline \multirow{4}{*}{Rescanning} & 2 mm-10\% & 1.02 \(\pm\) 0.04 & 0.11 \(\pm\) 0.01 & 95.9 \(\pm\) 0.5 & 96 \(\pm\) 3 & 91 \(\pm\) 3 & 369 \(\pm\) 2 \\  & 6 mm-10\% & 1.00 \(\pm\) 0.04 & 0.13 \(\pm\) 0.02 & 95.7 \(\pm\) 0.5 & 92 \(\pm\) 3 & 86 \(\pm\) 3 & \\  & 12 mm-10\% & 1.02 \(\pm\) 0.04 & 0.20 \(\pm\) 0.03 & 95.2 \(\pm\) 0.5 & 93 \(\pm\) 3 & 83 \(\pm\) 4 & \\  & 20 mm-10\% & 1.00 \(\pm\) 0.04 & 0.28 \(\pm\) 0.04 & 91.4 \(\pm\) 0.8 & 74 \(\pm\) 6 & 59 \(\pm\) 6 & \\ \hline \multirow{4}{*}{DIBH} & 1 s-1 mm & 1.00 \(\pm\) 0.04 & 0.11 \(\pm\) 0.02 & 95.9 \(\pm\) 0.3 & 96 \(\pm\) 2 & 91 \(\pm\) 3 & \\  & 2 s-2 mm & 0.99 \(\pm\) 0.04 & 0.12 \(\pm\) 0.02 & 93.8 \(\pm\) 0.8 & 91 \(\pm\) 5 & 84 \(\pm\) 5 & 340 \(\pm\) 6 \\ \cline{1-1}  & 3 s-3 mm & 0.96 \(\pm\) 0.04 & 0.12 \(\pm\) 0.02 & 92.9 \(\pm\) 0.9 & 88 \(\pm\) 7 & 79 \(\pm\) 8 & \\ \hline \multirow{2}{*}{Gating} & 12 mm-0\% & 0.99 \(\pm\) 0.03 & 0.11 \(\pm\) 0.01 & 95.9 \(\pm\) 0.4 & 97 \(\pm\) 2 & 91 \(\pm\) 3 & 209 \(\pm\) 9 \\  & 12 mm-10\% & 0.99 \(\pm\) 0.04 & 0.10 \(\pm\) 0.01 & 95.7 \(\pm\) 0.4 & 93 \(\pm\) 3 & 84 \(\pm\) 5 & 208 \(\pm\) 7 \\ \hline \end{tabular} \({}^{\star}\) Not available.  
\end{table} 
Table 1: Summary of quantitative results for dose distributions obtained using moving film irradiated with different beam delivery modalities. All data are presented as mean \(\pm\) SD. Abbreviations: SD = standard deviation; DIBH = deep inspiration breath-hold; ROI = region of interest; RMS = root mean square; and GPR = gamma passing rate. Figure 5: An example of the dose distributions (beam’s eye view) with the worst case GPR measured by (**a**) the stationary and moving films irradiated with different perpendicular motion patterns using different beam delivery modalities: (**b–e**) FB irradiation without motion mitigation, (**f–h**) FB irradiation with rescanning, (**i,j**) DIBH irradiation, and (**k,l**) respiratory-gated irradiation. The color maps are labeled as “Modality [Motion pattern]”. The black color indicates out of range. Abbreviations: GPR = gamma passing rate; FB = free breathing; Resc = rescanning; and DIBH = deep inspiration breath-hold. The DIBH technique was more effective than rescanning in minimizing the interplay effect in terms of dose metrics. It provided an average \(D_{\text{ROI2}}\) of 0.12 for all the motion patterns used, while the \(D_{\text{ROI2}}\) with rescanning was up to 0.28. In addition, the DIBH technique resulted in a higher \(H_{RMS}\) and \(GPR_{3\%/2\text{mm}}\) of at least 93% and 79%, respectively, compared to 91% and 59% with rescanning on average (Table 1). The random inter-BH variation caused similar dosimetric effects as the systematic regular FB motion. These effects were manifested as hot and cold spots and slight dose blurring along the direction of motion (Figures 5j and 6j). The \(D_{\text{ROI1}}\) decreased by an average of 4% when the inter-BH variation was increased to 3 mm (\(p\) = 0.02).