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Table 2 Summary of daily volumetric and positional data

From: Per-fraction positional and dosimetric performance of prone breast tangential radiotherapy on Halcyon™ linear accelerator assessed with daily rapid kilo-voltage cone beam computed tomography: a single-institution pilot study

Variable Value, median (range) Mean ± Stdev
Contour volumes [cc]   
 Breast PTV Vol 1095.20 (654.20–1343.70) 1040.21 ± 218.26
 Breast PTV Eval Vol 899.90 (540.70–1149.80) 852.00 ± 196.96
Daily couch shift [cm]   
 LAT 0.07 (− 2.26 to 2.28) 0.05 ± 0.92
 LNG  − 0.13 (− 2.10 to 1.35)  − 0.12 ± 0.70
 VRT  − 0.14 (− 2.20 to 1.93)  − 0.13 ± 0.63
 MAG 1.08 (0.27–2.78) 1.19 ± 0.57
PTV Eval residual shift [cm]   
 LAT  − 0.04 (− 0.35 to 0.32)  − 0.03 ± 0.12
 LNG 0.07 (− 0.38 to 0.47) 0.05 ± 0.19
 VRT 0.06 (− 0.32 to 0.43) 0.05 ± 0.13
 MAG 0.25 (0.05–0.49) 0.26 ± 0.10
BODY V95% residual shift [cm]   
 LAT  − 0.01 (− 0.60 to 0.46)  − 0.03 ± 0.22
 LNG  − 0.04 (− 0.53 to 0.66)  − 0.04 ± 0.18
 VRT 0.05 (− 0.58 to 0.43) 0.03 ± 0.16
 MAG 0.27 (0.04–0.80) 0.30 ± 0.15
Daily SSD [cm]   
 Lateral beam 85.45 (80.80–95.70) 86.24 ± 3.91
 Medial beam 102.75 (94.70–104.80) 102.00 ± 2.82
 Lateral beam deviation from planned 0.10 (− 2.10 to 1.30) 0.08 ± 0.58
 Medial beam deviation from planned 0.10 (− 0.50 to 1.30) 0.18 ± 0.42
Target contour DSC   
 Breast PTV Eval 0.93 (0.88–0.97) 0.93 ± 0.02
 BODY V95% 0.92 (0.88–0.96) 0.92 ± 0.02
Patient weight [%]   
 Deviation from planned/simulation  − 0.48 (− 6.50 to 4.71)  − 0.64 ± 2.69
  1. cc, centimeter cubed (cm3); PTV Eval, planning treatment volume for evaluation; LAT, lateral; VRT, vertical; LNG, longitudinal; MAG, magnitude; SSD, source-to-surface distance; DSC, dice similarity coefficient; Stdev, standard deviation