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Table 6 Techniques of IMRT delivery ± comparison with 2D/3D techniques

From: Intensity modulated radiotherapy for sinonasal malignancies with a focus on optic pathway preservation

Ref.

Techniques

Dose prescribed

ON/OC dose constraints

Findings

Adams [30]

IMRT vs. 2D/3D RT

64 Gy/32 frx

Contra-lateral ON Dmax ≤ 60 Gy

On average, IMRT decreased the Dmax to the contralateral ON when compared with 2D & 3D RT(56.4 Gy vs. 65.7 Gy & 64.2 Gy), and minimized volume receiving <95% prescribed dose (8.5% vs. 15.1% & 14.7%)

Lee [31]

Static IMRT vs. 3D CRT

70 Gy/35 frx

Dmax ≤ 60 Gy

IMRT improved PTV coverage by the dose prescribed in general (93.0 ± 2.2% vs. 89.0 ± 4.8%, p = 0.005), no benefit in OAR sparing.

O’Daniel [32]

Modulator IMRT vs. 3D CRT

60-66 Gy/30–33 frx

Dmax ≤ 54 Gy

35% minimal transmission IMRT decreased Dmax to the ON/OC (p < 0.05), and is comparable to static IMRT in ON/OC sparing

Huang [33]

15 beam IMRT; Sequential tomotherapy (MIMic); 5-field 3D CRT; 3-field 2D RT

Minimal dose of 60 Gy to CTV & 70 Gy to GTV

Dmax ≤ 54 Gy

IMRT achieved better GTV coverage & sparing of OC when compared to 2D & 3D RT

Mock [34]

Passive scanning PT; IMRT; 3D CRT; 2D RT

60-70 Gy to the PTV

≤ 50 Gy to ON/OC

Not significantly different, 3D CRT & IMRT achieved better OAR sparing than 2D RT. PT decreased OAR mean dose by > 60% when compared to 3D CRT & IMRT.

Pacholke [35]

6-7 beam coplanar IMRT; 3 field; 4 field

70.2 Gy/39 frx to PTV

Case dependent

IMRT did not demonstrate any clear advantage over conventional 4 field plans.

Claus [36]

4-11 beam IMRT, 5/9 beam setups were coplanar

70 Gy/35 frx

≤ 60 Gy

Increased beam & segment number and non-coplanar setup may lead to improved PTV dose coverage and improved OAR sparing in selected cases.

Wang [37]

9 beam coplanar IMRT; 5 beam non-coplanar/coplanar IMRT

63 Gy/35 frx to PTV

Dmax < 50 Gy

Target dose better, mean dose to both ON & Dmax to the contralateral ON was significantly lower with the 5 beam approach.

Serre [38]

5 beam coplanar IMRT; 5 beam non-coplanar IMRT

n/a

Dmax < 55 Gy

No obvious difference in OAR sparing & target dose coverage was found

Sheng [39]

7 beam non-coplanar IMRT vs. HT

50 Gy/25 frx

n/a

Comparable PTV dose coverage & OAR sparing, although better sparing of ipsilateral eye & lens

Chen [40]

9-11 beam coplanar IMRT vs. HT

70 Gy/35 frx

Dmax: 54 Gy

HT reduced Dmax to OC, ipsilateral ON & retina; improved target dose homogeneity

Tsien [41]

9 beam coplanar IMRT vs. 3D CRT

70 Gy/35 frx

Dmax ≤ 60 Gy

Clinical decision to spare the contralateral ON only can lead to improved PTV dose coverage and improved TCP when compared to bilateral ON sparing IMRT and 3D CRT.

  1. ON optic nerve, OC optic chiasm, PTV planning target volume, OAR organs at risk, PT proton therapy, HT helical tomotherapy, frx fraction.