Background: The purpose of this study was to investigate the feasibility and dosimetric characteristics of dose painting for non-enhancing low-grade gliomas (NE-LGGs) guided by three-dimensional arterial spin labeling (3D-ASL) perfusion magnetic resonance imaging.Methods: Eighteen patients with NE-LGGs were enrolled. 3D-ASL, T2 fluid attenuated inversion recovery (T2 FLAIR) and contrast-enhanced T1-weight magnetic resonance images were obtained. The gross tumor volume (GTV) was delineated on

more »

... T2 FLAIR. The hyper-perfusion region of the GTV (GTV-ASL) was determined by 3D-ASL, and the GTV-SUB was obtained by subtracting the GTV-ASL from the GTV. The planning target volume (PTV), PTV-ASL and PTV-SUB were developed by expanding the external margins of the GTV, GTV-ASL and GTV-SUB, respectively. Three plans were established for each patient: in plan 1, the traditional homogeneous prescription dose to the PTV was 45-60 Gy; in plan 2 and plan 3, the dose to the PTV-ASL increased by 10-20% based on plan 1, without the maximum dose constraint to the PTV-ASL in plan 3. The dosimetric differences among the three plans were compared.Results: Compared with plan 1, the dose to 2% (D2%), 98% (D98%) and 50% (Dmean) of PTV-ASL volumes increased by 14.67%, 16.17% and 14.31% in plan 2 and 19.84%, 15.52% and 14.27% in plan 3, respectively (P < 0.05); the D2% of the PTV, PTV-SUB increased by 11.89% and 8.34% in plan 2, 15.89% and 8.49% in plan 3, respectively (P< 0.05). The PTV coverages were comparable among the three plans (P > 0.05). In Plan 2 and plan 3, the conformity indexs decreased by 18.60% and 12.79%; while the homogeneity indexs increased by 1.43 and 2 times (P<0.05). Compared with plan 1, the D0.1cc of brain stem and Dmax of optic chiasma slightly increased in plan 2 and plan 3, but the absolute doses met the dose constraint. The other organs at risk were similar among the three plans (P > 0.05).Conclusions: The sub-volume with hyper-perfusion for NE-LGG radiotherapy can be segmented based on the perfusion difference guided by 3D-ASL. And the radiation dose to the hyper-perfusion area increased safely by 10-20% through dose painting.