Table 4. Comparative planning studies in thoracic tumours.
| Paper [ref] VMAT commercial system | Number of patients | Stage and dose | Comparison | PTV | OAR | MU per fraction | Treatment time per fraction |
| McGrath et al [120] | 21 | Stage Ia NSCLC SBRT 48 Gy in 12 fractions | 3D-CRT (7−10 non-coplanar) vs VMAT (single partial arc) | VMAT better than 3D-CRT for conformity at 80% and 50% isodose levels. No difference in homogeneity | VMAT better than 3D-CRT at sparing lung (V20 Gy, V12.5 Gy, V10 Gy, V5 Gy). No significant difference in mean dose to other OARs | VMAT, 2360; 3D-CRT, 2235 | VMAT reduced treatment time by 37−63% compared with 3D-CRT |
| Ong et al [121] Rapidarc | 18 | Stage I NSCLC SBRT 54Gy in 3 fractions 55Gy in 5 fractions 60Gy in 8 fractions | 3D-CRT non-coplanar (10F) vs DCA vs IMRT (9−10F coplanar), SW vs VMAT (DA) | VMAT better than 3D-CRT, DCA and IMRT for conformity at 80% and 60% isodose levels | VMAT – higher lung doses (V20Gy,V5Gy) compared with 3D-CRT (no significant difference with IMRT). VMAT − better sparing of chest wall (V45Gy, V30Gy, V20Gy) compared to 3D-CRT, DCA and IMRT | VMAT,1800−4320; 3D-CRT, 1343−3222; DCA, 1402−3364; IMRT, 3338−8010 | VMAT, 3.9−10.5 min; 3D-CRT, 11.6 min; IMRT, 12 min |
| Holt et al [122] SmartArc | 27 | Stage I/IIa NSCLC SBRT 54Gy in 3 fractions | Coplanar IMRT (9F) vs non-coplanar IMRT (12−16F) vs VMAT (DA) | Similar PTV coverage VMAT better than coplanar IMRT but inferior to non-coplanar IMRT for conformity at 50% isodose level. Non-coplanar IMRT better than coplanar IMRT for conformity at 75% and 50% isodose levels | VMAT inferior to non-coplanar IMRT for lung V20Gy, spinal cord (Dmax), oesophagus (Dmax) and chest wall V30Gy. VMAT and non-coplanar IMRT better than coplanar IMRT for lung V20Gy, spinal cord and oesophageal Dmax | VMAT, 3428; coplanar IMRT, 3335; non-coplanar IMRT, 3313 | VMAT, 6.5 min; Coplanar IMRT, 17 min; non-coplanar IMRT, 23.7 min |
| Brock et al [123] | 5 | Stage I NSCLC SBRT 60Gy in 8 fractions | Coplanar and non-coplanar CRT (3F, 5F, 7F, 9F) vs VMAT | Non-coplanar and VMAT better than co-planar for PTV coverage | Non-coplanar CRT better than coplanar CRT for lung V11Gy (no significant difference for V20Gy). VMAT slightly higher V11Gy and lower V20Gy compared with non-coplanar CRT (not statistically significant) | VMAT, 2.13 min; non-coplanar (5F), 12.67 min; (7F), 7.75 min | |
| Rao et al [61] SmartArc | 6 (of 18) | Not specified | IMRT (7F,SS) vs VMAT (SA) vs HT | Similar PTV coverage, homogeneity | IMRT – slightly lower lung mean dose and V20Gy (not statistically significant) | VMAT, 476; IMRT, 569 | VMAT, 2.1 min; IMRT, 7.9 min; HT, 5.4 min |
| Scorsetti [128] RapidArc | 6 | Mesothelioma | IMRT (9F,SW) vs VMAT (DA) | Similar PTV coverage | VMAT better than IMRT at sparing some OAR (contralateral lung V20Gy, kidney D1%, heart mean dose, liver mean dose) | VMAT, 734; IMRT, 2195 | VMAT, 3.7 min; IMRT, 13.4 min |
VMAT, volumetric modulated arc therapy; PTV, planning target volume; OAR, organs at risk; MU, monitor units; NSCLC, non small cell lung cancer; SBRT, stereotactic body radiotherapy; Gy, Gray; 3D-CRT, three-dimensional conformal radiotherapy; V20Gy, volume receiving ≥20Gy; V12.5Gy, volume receiving ≥12.5Gy; V10Gy, volume receiving ≥10Gy, V5Gy, volume receiving ≥5Gy; DCA, dynamic conformal arcs; IMRT, intensity modulated radiotherapy; V45Gy, volume receiving ≥45Gy; V30Gy, volume receiving ≥30Gy;3F, three field; 5F, five field; 7F, seven field; 9F, nine field; 12F, twelve field, 16F, sixteen field; SW, sliding window; SS, step-and-shoot; SA, single arc; DA, double arc; Dmax, maximum dose; V11Gy, volume receiving ≥11Gy; HT, helical tomotherapy; D1%, dose to 1% of volume.