Functional image-guided dose escalation in gliomas using of state-of-the-art photon vs. proton therapy

Acta Oncol. 2017 Jun;56(6):826-831. doi: 10.1080/0284186X.2017.1285498. Epub 2017 Feb 28.


Background: Recurrences of glioma are usually local, suggesting the need for higher tumor dose. We investigated the boundaries for dose escalation of an 18F-fluoro-ethyl-tyrosine positron emission tomography defined target by intensity-modulated photon therapy (IMRT), volumetric modulated arc therapy (VMAT) and intensity-modulated proton therapy (IMPT).

Materials and methods: Standard dose (60 Gy) and dose-escalated plans were calculated for seven patients using IMRT, VMAT and IMPT. The achieved boost dose, the dose to the organs at risk (OAR), the dose homogeneity (defined as overdose volume, ODV) and the ratio of the 30 Gy isodose curve and the boost volume (R30) were compared. The risk of radionecrosis was estimated using the ratio of the dose volume histograms of the brain (range 30-60 Gy).

Results: The mean boost dose was 77.1 Gy for IMRT, 79.2 Gy for VMAT and 85.1 GyE for IMPT. Compared with the standard plan, the ODV was unchanged and the R30 increased (17%) for IMRT. For VMAT, the ODV decreased (7%) and the R30 was unchanged whereas IMPT substantially decreased ODV (61%), R30 (22%), OAR doses as well as the risk of radionecrosis.

Conclusions: Dose escalation can be achieved with IMRT, VMAT and IMPT while respecting normal tissue constraints, yet with IMPT being most favorable.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Brain Neoplasms / diagnostic imaging
  • Brain Neoplasms / pathology
  • Brain Neoplasms / radiotherapy*
  • Female
  • Glioma / diagnostic imaging
  • Glioma / pathology
  • Glioma / radiotherapy*
  • Humans
  • Image Processing, Computer-Assisted / methods
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / diagnostic imaging
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / radiotherapy*
  • Organs at Risk / radiation effects
  • Photons / therapeutic use*
  • Positron-Emission Tomography
  • Proton Therapy*
  • Radiotherapy Dosage
  • Radiotherapy Planning, Computer-Assisted / methods*
  • Radiotherapy, Image-Guided / methods*
  • Radiotherapy, Intensity-Modulated / methods