Author, as appears in the article.: May L; Hardcastle N; Hernandez V; Saez J; Rosenfeld A; Poder J
Department: Ciències Mèdiques Bàsiques
URV's Author/s: Hernandez Masgrau, Victor
Keywords: Radiotherapy, intensity-modulated Radiotherapy planning, computer-assisted Radiotherapy dosage Radiosurgery Radiometry Plan robustness Plan complexity Organs at risk Linear accelerator-based radiotherapy Intra-cranial stereotactic radiosurgery Humans Delivery errors Brain neoplasms
Abstract: BackgroundThe use of modulated techniques for intra-cranial stereotactic radiosurgery (SRS) results in highly modulated fields with small apertures, which may be susceptible to uncertainties in the delivery device.PurposeThis study aimed to quantify the impact of simulated delivery errors on treatment plan dosimetry and how this is affected by treatment planning system (TPS), plan geometry, delivery technique, and plan complexity. A beam modelling error was also included as context to the dose uncertainties due to treatment delivery errors.MethodsDelivery errors were assessed for multiple-target brain SRS plans obtained through the Trans-Tasman Radiation Oncology Group (TROG) international treatment planning challenge (2018). The challenge dataset consisted of five intra-cranial targets, each with a prescription of 20 Gy. Of the final dataset of 54 plans, 51 were created using the volumetric modulated arc therapy (VMAT) technique and three used intensity modulated arc therapy (IMRT). Thirty-five plans were from the Varian Eclipse TPS, 17 from Elekta Monaco TPS, and one plan each from RayStation and Philips Pinnacle TPS. The errors introduced included: monitor unit calibration errors, multi-leaf collimator (MLC) bank offset, single MLC leaf offset, couch rotations, and collimator rotations. Dosimetric leaf gap (DLG) error was also included as a beam modelling error. Dose to targets was assessed via dose covering 98% of planning target volume (PTV) (D98%), dose covering 2% of PTV (D2%), and dose covering 99% of gross tumor volume (GTV) (D99%). Dose to organs at risk (OARs) was assessed using the volume of normal brain receiving 12 Gy (V12Gy), mean dose to normal brain, and maximum dose covering 0.03cc brainstem (D0.03cc). Plan complexity was also assessed via edge metric, modulation complexity score (MCS), mean MLC gap, mean MLC speed, and plan modulation (PM).ResultsPTV D98% showed high robustness on average to most errors with the exception of a bank shift of 1.0 mm and large rotational errors ≥1.0° for either the couch or collimator. However, in some cases, errors close to or within generally accepted machine tolerances resulted in clinically relevant impacts. The greatest impact upon normal brain V12Gy, mean dose to normal brain, and D0.03cc brainstem was found for DLG error in alignment with other recent studies. All delivery errors had on average a minimal impact across these parameters. Comparing plans from the Monaco TPS and the Eclipse TPS, showed a lesser increase to V12Gy, mean dose to normal brain, and D0.03cc brainstem for Monaco plans (p < 0.01) when DLG error was simulated. Monaco plans also correlated to lower plan complexity. Using Spearman's correlation coefficient (r) a strong negative correlation (r ≤ -0.8) was found between the mean MLC gap and dose to OARs for DLG errors.ConclusionsReducing MLC complexity and using larger mean MLC gaps is recommended to improve plan robustness and reduce sensitivity to delivery and modelling errors. For cases in which the calculated dose distribution or dose indices are close to the clinically acceptable limits, this is especially important.
Thematic Areas: Radiology, nuclear medicine and imaging Radiology, nuclear medicine & medical imaging Medicine (miscellaneous) Medicina ii Medicina i Interdisciplinar General medicine Engenharias iv Engenharias ii Ciências biológicas iii Ciências biológicas ii Ciências biológicas i Ciência da computação Biotecnología Biophysics Astronomia / física Antropologia / arqueologia
licence for use: https://creativecommons.org/licenses/by/3.0/es/
Author's mail: victor.hernandez@urv.cat
Author identifier: 0000-0003-3770-8486
Record's date: 2024-09-07
Papper version: info:eu-repo/semantics/publishedVersion
Link to the original source: https://aapm.onlinelibrary.wiley.com/doi/10.1002/mp.16907
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Papper original source: Medical Physics. 51 (2): 910-921
APA: May L; Hardcastle N; Hernandez V; Saez J; Rosenfeld A; Poder J (2024). Multi-institutional investigation into the robustness of intra-cranial multi-target stereotactic radiosurgery plans to delivery errors.. Medical Physics, 51(2), 910-921. DOI: 10.1002/mp.16907
Article's DOI: 10.1002/mp.16907
Entity: Universitat Rovira i Virgili
Journal publication year: 2024
Publication Type: Journal Publications
Repositori URV