Table 1.
Patient characteristics and target volumes.
Fig 1.
Radiation therapy plan and dose volume histogram.
(A) Sagittal computed tomography image of a dog with a stage IV sinonasal tumor with marked intracranial invasion with gross tumor volume (GTV) shown in pink and radiation dose with isodose lines of the IMRT plan in color. (B) Comparison of the dose volume histograms of target volumes (GTV pink, CTV light pink, PTV red) and organs at risk (left cornea orange, right cornea yellow, left eye dark green, right eye light green, lacrimal glands darker yellow, brain blue) between fixed-field IMRT (squares) and VMAT (triangles) plan of the dog depicted in A. The aspired dose volume constraints for eyes (D60<15 Gy) and cornea (D2<35.4 Gy) are depicted with a white X.
Table 2.
Mean relative doses for target volumes.
Fig 2.
Mean constraint dose to organs at risk.
Mean constraint dose to (A) 60% of the eye, (B) the lacrimal glands and (C) the dose to 2% of the corneae in the respective organ at risk in the high and lower dose region for each IMRT and VMAT treatment plans, respectively (for individual P-values see Table 3). IMRT: Intensity modulated radiation therapy; VMAT: Volumetric modulated arc therapy.
Table 3.
Organ at risk volume and actual constraint dose per plan.
Fig 3.
Mean monitor units and delivery time.
Monitor units and delivery time of fixed-field IMRT versus VMAT plans: (A) The mean number of monitor units was significantly higher for fixed-field IMRT (2446.0 (±1015.5)) versus VMAT plans (1033.2 (±107.8)) (p<0.01). (B) The median delivery time for fixed-field IMRT plans (6.16 minutes, IQR 2.2) was significantly longer compared to VMAT plans (2.63 minutes, IQR 0.25) (p<0.01). IMRT: Intensity modulated radiation therapy; VMAT: Volumetric modulated arc therapy.