Klinge, Thomas;
(2022)
Biologically effective dose (BED) treatment planning for Gamma Knife Radiosurgery.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Gamma Knife (GK) radiosurgery treats brain lesions through multiple targeted radiation exposures of varying duration and spatial distribution. Clinical radiosurgery treatment planning only considers the total amount of delivered radiation. A biologically effective dose (BED) model allows quantifying the damage induced in a tissue due to radiation exposure while accounting for cellular repair. With this thesis work, we explore the potential and feasibility of using the more complex BED formulation to generate biologically-aware treatment plans. To this end, we quantify the impact of changes in the temporal domain of treatment delivery (i.e. beam-off periods, order of delivery), which need to be considered at the treatment planning stage to avoid undesirable BED variations. The delivery sequence alone can incur variations in marginal BED by up to 14%. Consideration of treatment delivery timing and sequence creates a nonconvex nonlinear treatment planning problem that is too computationally expensive to solve in a time-sensitive clinical setting. We develop multiple optimisation techniques to identify the most suitable one for a clinical workflow. While a convex underestimator approach provides slightly improved solutions, it requires several orders of magnitude more computational resources than local optimisation approaches that reach similar performance in terms of plan quality. In consultation with our clinical collaborators, we devise a BED treatment planning workflow that further reduces the possible planning times by combining pre-computation of candidate solutions with interactive exploration and refinement of the final treatment plans. To evaluate this workflow, we develop a prototype treatment planning framework. We show that BED optimisation removes the time dependence and further increases plan quality. The results of the proof-of-concept workflow demonstrate the feasibility of a future clinical application of BED planning in GK radiosurgery.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Biologically effective dose (BED) treatment planning for Gamma Knife Radiosurgery |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10158520 |
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