Multi-institutional dosimetric delivery assessment of intracranial stereotactic radiosurgery on different treatment platforms

Alexis Dimitriadis; Yatman Tsang; Russell A S Thomas; Antony L Palmer; David Eaton; Jonathan Lee; Rushil Patel; Ileana Silvestre Patallo; Clare Gouldstone; Julia A D Snaith; Karen J Kirkby; Andrew Nisbet; Catharine H Clark

doi:10.1016/j.radonc.2020.05.024

Multi-institutional dosimetric delivery assessment of intracranial stereotactic radiosurgery on different treatment platforms

Radiother Oncol. 2020 Jun:147:153-161. doi: 10.1016/j.radonc.2020.05.024. Epub 2020 May 20.

Affiliations

¹ Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, UK; Radiation Dosimetry Group, National Physical Laboratory, Teddington, UK; Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK. Electronic address: alex@physicsconsulting.co.uk.
² Radiotherapy Trials Quality Assurance Group, Mount Vernon Hospital, London, UK.
³ Radiation Dosimetry Group, National Physical Laboratory, Teddington, UK.
⁴ Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, UK; Medical Physics Department, Portsmouth Hospitals NHS Trust, Portsmouth, UK.
⁵ The Christie NHS Foundation Trust, Manchester, UK; Institute of Cancer Sciences, University of Manchester, UK.
⁶ Radiation Dosimetry Group, National Physical Laboratory, Teddington, UK; University College London, UK.
⁷ Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, UK; Radiation Dosimetry Group, National Physical Laboratory, Teddington, UK; Radiotherapy Trials Quality Assurance Group, Mount Vernon Hospital, London, UK; Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK.

PMID: 32445860
DOI: 10.1016/j.radonc.2020.05.024

Abstract

Background and purpose: Assessment of dosimetric accuracy of radiosurgery on different treatment platforms.

Material and methods: Thirty-three single fraction treatment plans were assessed at thirty centres using an anthropomorphic head phantom with target and brainstem structures. The target being a single irregular shaped target, ~8 cc, 10 mm from the brainstem. The phantom was "immobilised", scanned, planned and treated following the local protocols. EBT-XD films and alanine pellets were used to measure absolute dose, inside both the target and the brainstem, and compared with TPS predicted dose distributions.

Results: PTV alanine measurements from gantry-based linacs showed a median percentage difference to the TPS of 0.65%. Cyberknife (CK) had the highest median difference of 2.3% in comparison to the other platforms. GammaKnife (GK) showed the smallest median of 0.3%. Similar trends were observed in the OAR with alanine measurements showing median percentage differences of1.1%, 2.0% and 0.4%, for gantry-based linacs, CK and GK respectively. All platforms showed comparable gamma passing rates between axial and sagittal films.

Conclusions: This comparison has highlighted the dosimetric variation between measured and TPS calculated dose for each delivery platform. The results suggest that clinically acceptable agreement with the predicted dose distributions is achievable by all treatment delivery systems.

Keywords: Alanine; Anthropomorphic phantom; Audit; Dosimetry; Radiochromic film; Radiosurgery.

Publication types

Multicenter Study
Research Support, Non-U.S. Gov't

MeSH terms

Humans
Particle Accelerators
Phantoms, Imaging
Radiometry
Radiosurgery*
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted