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Table 2 Planning target volume homogeneity, conformity, dosimetry and organ at risk doses in non-coplanar versus coplanar IMRT plans

From: The treatment of extensive scalp lesions using coplanar and non-coplanar photon IMRT: a single institution experience

No.1 Planarity2 HI3 CI [95%]4 CI [98%]4 PTV coverage5 PTV Dmax6Gy (%) PTV Dmin Gy (%) Max. air gap mm Bolus size mm Treatment duration7mean min Dose gradient Gy/mm Mean brain dose Gy (%) Max. brain stem dose Gy (%) Max. optic chiasm dose Gy (%) Max. optic nerve dose8Gy (%) Mean lens dose8Gy (%) Max brain dose Gy (%)
1 coplanar .25 .66 .54 .83 38.3 9 8 8 15 1.05 13.3 23.5 11.2 14.3 (47.8), 4.7 (15.6), 30.4
(127.7) (30) (44.3) (78.3) (37.4) 11.3 (37.7) 5.9 (19.7) (101.3)
non-coplanar .17 .69 .65 .88 34.8 20.8 8 8 n/a .92 15.2 20.5 5.3 9 (30), 7.6 (25.3), 31.1
(115.9) (82.7) (50.8) (68.2) (17.7) 8.3 (27.7) 8.4 (28) (103.6)
2 coplanar .21 .45 .42 .84 34.9 23.7 8 7 16 .7 14.4 16.5 7.5 10.6 (35.2), 4 (13.2), 31.7
(116.4) (79) (47.9) (55.1) (24.9) 10.9 (36.3) 4.1 (11.9) (105.7)
non-coplanar .15 .56 .47 .88 33.8 24.4 8 7 n/a .8 14.5 12.5 3.2 13.4 (44.7), 4.8 (16.1), 32.2
(112.8) (81.3) (48.2) (41.6) (10.7) 11.4 (38) 5.2 (17.3) (107.4)
3 non-coplanar .17 .47 .42 .88 56.9 40.4 5 8 18 1.25 21.4 17.5 7.7 20.8 (41.6), 7.5 (14.9 ), 53.5
(113.8) (80.8) (42.8) (35.1) (15.5) 21.8 (43.6) 7.8 (15.6) (107)
coplanar .18 .54 .45 .86 57.8 41.5 5 8 n/a 1.59 23.2 15.8 14.2 18.3 (36.6), 5.8 (11.6), 53.6
(115.6) (83) (46.3) (31.6) (28.4) 17.6 (35.1) 5.9 (11.7) (107.2)
4 non-coplanar .12 .49 .45 .96 58.5 42.3 3 5 19 1.17 23 3.7 4.4 24.8 (49.5), 6.7 (10.3), 52.5
(116.9) (84.6) (46) (7.4) (8.8) 23.5 (46.9) 5.9 (11.9) (105)
coplanar .14 .59 .51 .92 55.1 40 3 5 n/a 1.42 24.8 10 9.1 20.5 (41), 6.5 (12.9), 54.5
       (110.3) (80)      (49.7) (20) (18.2) 19.6 (39.3) 7.6 (15.2) (109.1)
  1. 1patient number 2the upper line refers to the originally executed treatment plan and the lower line to the additionally calculated corresponding plan using opposite planarity for direct comparison 3homogeneity index according to ICRU 83 4conformity index according to Paddick et al. referring to 95% and 98% isodose 5ratio of V95 and corresponding PTV 6dose hot spot 7per session in originally carried out treatmemt plans 8right, left.