## 3 Results  
Table 2 summarizes the results of CT image analysis. As compared with metallic ports, RFID ports tremendously decreased the distortion on CT images, with the exception of point D (axilla). In point E (LAD), the average HU difference for the reference values of the RFID and metallic ports were \(-2.86\) (\(p=0.059\)) and \(-15.16\) (\(p=0.005\)), respectively. In addition, both ports showed statistically significant average HU differences for the reference values in points A, B, and C on the chest wall. Table 3 summarizes the results of the dosimetric parameters for PTVs and OARs between the RFID and metallic ports. Dose distributions for the RFID and metallic ports in the axial view are shown in Figure 4. The volumes of PTV\({}_{\text{RFID}}\) and PTV\({}_{\text{magnet}}\) were 921.65 cm\({}^{3}\) and 951.9 cm\({}^{3}\), respectively. The optimization algorithm was balanced for the PTV coverage, and planned PTV coverage for both the metallic and RFID ports was acceptable. The percentage differences between HI, CI, QOC, and V95 of the PTV for both ports narrowly ranged from 0 to 2.19. However, V\({}_{\text{107}}\) of the PTV was 71.70% for RFID ports and 80.80% for metallic ports, indicating a percentage difference of 11.93. The V\({}_{\text{5 Gy}}\), V\({}_{\text{10 Gy}}\), V\({}_{\text{15 Gy}}\), V\({}_{\text{20 Gy}}\), V\({}_{\text{30 Gy}}\), and D\({}_{\text{mean}}\) values of the heart in the RFID ports were lower than those in the metallic ports. Specifically, the percentage differences between the RFID and metallic ports was 25.97 (22.91% vs. 29.75%) for V\({}_{\text{5 Gy}}\), 54.66 (6.54% vs. 11.46%) for V\({}_{\text{10 Gy}}\), 56.84 (2.77% vs. 4.97%) for V\({}_{\text{15 Gy}}\), 65.70 (1.39% vs. 2.75%) for V\({}_{\text{20 Gy}}\), 98.90 (0.23% vs. 0.68%) for V\({}_{\text{30 Gy}}\), and 18.66 (4.08 Gy vs. 4.92 Gy) for D\({}_{\text{mean}}\). Similarly, the V\({}_{\text{5 Gy}}\), V\({}_{\text{15 Gy}}\), V\({}_{\text{20 Gy}}\), V\({}_{\text{30 Gy}}\), and D\({}_{\text{mean}}\) values of the ipsilateral lung in the RFID port were also lower than those in the metallic port. For the ipsilateral lung, the percentage differences between the RFID and metallic ports was 7.41 (36.08% vs. 38.86%) for V\({}_{\text{5 Gy}}\), 13.63 (12.85% vs. 14.73%) for V\({}_{\text{15 Gy}}\), 14.47 (7.50% vs. 8.67%) for V\({}_{\text{20 Gy}}\), 23.16 (1.87% vs. 2.36%) for V\({}_{\text{30 Gy}}\), and 7.62 (6.94 Gy vs. 7.62 Gy) for D\({}_{\text{mean}}\). Our results showed that higher V\({}_{\text{DGy}}\) values were \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline \multirow{2}{*}{**Points of the Reference ROIs**} & \multicolumn{3}{c}{**RFID Port**} & \multicolumn{3}{c}{**Metallic Port**} \\ \cline{2-7}  & **Averaged HU** & **Averaged HU** & **Averaged HU** & **Averaged HU** & **Averaged HU** & **_p-Value_ \\ \hline A (central chest wall) & \(-2.73\) & \(-18.33\) & 0.043 & \(118.57\) & \(-139.63\) & 0.007 \\ B (medial chest wall) & \(-19.36\) & \(8.17\) & 0.028 & \(-34.62\) & 23.43 & 0.017 \\ C (lateral chest wall) & \(-37.36\) & \(14.93\) & 0.028 & \(-74.37\) & 51.94 & 0.005 \\ D (axilla) & \(-0.92\) & \(-15.14\) & 0.005 & \(-12.32\) & \(-3.74\) & 0.169 \\ E (left anterior descending artery) & \(32.41\) & \(-2.86\) & 0.059 & \(44.71\) & \(-15.16\) & 0.005 \\ \hline \hline \end{tabular} ROI, region of interest; RFID, radio frequency identification device; HU, Hounsfield unit.  
\end{table} 
Table 2: Comparison of Hounsfield units. associated with greater percentage differences in the heart and ipsilateral lung. Dose-volume histogram for PTV and OARs in RT plans of both RFID port and metallic port are shown in Figure 5.  
Figure 4: The dose distributions for the radio frequency identification ports and metallic ports in axial view. The isodose lines correspond to 110% (red), 105% (pink), 100% (yellow), 95% (orange), 90% (green), 85% (cyan), 80% (blue), 70% (light green), 50% (brown), 30% (dark green), and 15% isodose (dark blue). (**a**) RFID port; (**b**) metallic port.