Dosimetric comparison of Gamma Knife® IconTM and linear accelerator-based fractionated stereotactic radiotherapy (FSRT) plans for the re-irradiation of large (>14 cm3) recurrent glioblastomas

Matthew E Schelin; Haisong Liu; Ayesha Ali; Wenyin Shi; Yan Yu; Karen E Mooney

Dosimetric comparison of Gamma Knife® Icon^TM and linear accelerator-based fractionated stereotactic radiotherapy (FSRT) plans for the re-irradiation of large (>14 cm³) recurrent glioblastomas

J Radiosurg SBRT. 2021;7(3):233-243.

Authors

Matthew E Schelin¹, Haisong Liu¹, Ayesha Ali¹, Wenyin Shi¹, Yan Yu¹, Karen E Mooney¹

Affiliation

¹ Department of Radiation Oncology, Thomas Jefferson University, Bodine Center for Radiation Therapy, 111 S. 11th Street, Philadelphia, PA 19107, USA.

PMID: 33898087
PMCID: PMC8055238

Abstract

Our objective is to investigate dosimetric differences between clinically deliverable Gamma Knife^® (GK) Icon™ and linac-based FSRT plans on the basis of normal brain dose sparing for large (>14 cm³) recurrent glioblastomas (GBM). Sixteen patients with large, recurrent GBM were treated using re-irradiation via linac-based FSRT, 35 Gy in 10 fractions. For each patient, a new GK FSRT plan was created in Leksell GammaPlan^® V11 (LGP). To maintain clinical deliverability, the LGP optimization included a planning goal of treatment time <20 minutes per fraction. Dosimetric comparison of coverage and normal brain dose between the linac and GK treatment plans was performed in MIM. The GK FSRT plans had significantly (p < 0.05) lower mean normal brain dose values (-8.85%), mean values of normal brain V20 (-32.4%) and V12 (-25.9%), and a lower mean V4 (-10.0%). GK FSRT plans have the potential to reduce the risk of radiation-related toxicities.

Keywords: Gamma Knife Icon; fractionated stereotactic radiotherapy; glioblastoma; recurrence.