title: Combined stereotactic biopsy and stepping-source interstitial irradiation of glioblastoma multiforme.
abstract: Patients diagnosed with glioblastoma multiforme receiving stereotactic biopsy only either due to tumor localization or impaired clinical status face a devastating prognosis with very short survival times. One strategy to provide an initial cytoreductive and palliative therapy at the time of the stereotactic biopsy is interstitial irradiation through the pre-defined trajectory of the biopsy channel. We designed a novel treatment planning system and evaluated the treatment potential of a fixed-source and a stepping-source algorithm for interstitial radiosurgery on non-spherical glioblastoma in direct adjacency to risk structures. Using both setups, we show that radiation doses delivered to 100% of the gross tumor volume shifts from sub-therapeutic (10-12 Gy) to sterilizing single doses (25-30 Gy) when using the stepping source algorithm due to improved sparing of organs-at-risk. Specifically, the maximum doses at the brain stem were 100% of the PTV dose when a fixed central source and 38% when a stepping-source algorithm was used. We also demonstrated precision of intracranial target points and stability of superficial and deep trajectories using both a phantom and a body donor study. Our setup now for the first time provides a basis for a clinical proof-of-concept trial and may widen palliation options for patients with limited life expectancy that should not undergo time-consuming therapies.
authors.affiliation: Department of Neurosurgery, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Brehmer
authors.affiliation: Experimental Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Christian V
authors.initials: CV
authors.lastname: Guthier
authors.affiliation: Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Clausen
authors.affiliation: Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Schneider
authors.affiliation: Department of Neurosurgery, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Dirk-Michael
authors.initials: DM
authors.lastname: Schulte
authors.affiliation: Carl Zeiss Meditec AG, Oberkochen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Benker
authors.affiliation: Department of Orthopedic and Trauma Surgery, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Frederic
authors.initials: F
authors.lastname: Bludau
authors.affiliation: Medical Radiation Physics/Radiation Protection, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Glatting
authors.affiliation: Department of Pathology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Marx
authors.affiliation: Department of Neurosurgery, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Schmiedek
authors.affiliation: Experimental Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hesser
authors.affiliation: Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Frederik
authors.initials: F
authors.lastname: Wenz
authors.affiliation: Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany - frank.giordano@umm.de.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Giordano
mesh_terms: D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005909:Glioblastoma / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D011878:Radiotherapy / Q000379:methods*; D013238:Stereotaxic Techniques