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Purpose: Plan complexity and robustness are two essential aspects of treatment plan quality but there is a great variability in their management in clinical practice. This study reports the results of the 2020 ESTRO survey on plan complexity and robustness to identify needs and guide future discussions and con-sensus.Methods: A survey was distributed online to ESTRO members. Plan complexity was defined as the mod-ulation of machine parameters and increased uncertainty in dose calculation and delivery. Robustness was defined as a dose distribution's sensitivity towards errors stemming from treatment uncertainties, patient setup, or anatomical changes.Results: A total of 126 radiotherapy centres from 33 countries participated, 95 of them (75%) from Europe and Central Asia. The majority controlled and evaluated plan complexity using monitor units (56 centres) and aperture shapes (38 centres). To control robustness, 98 (97% of question responses) photon and 5 (50%) proton centres used PTV margins for plan optimization while 75 (94%) and 5 (50%), respectively, used margins for plan evaluation. Seventeen (21%) photon and 8 (80%) proton centres used robust opti-misation, while 10 (13%) and 8 (80%), respectively, used robust evaluation. Primary uncertainties consid-ered were patient setup (photons and protons) and range calculation uncertainties (protons). Participants expressed the need for improved commercial tools to control and evaluate plan complexity and robust-ness.Conclusion: Clinical implementation of methods to control and evaluate plan complexity and robustness is very heterogeneous. Better tools are needed to manage complexity and robustness in treatment plan-ning systems. International guidelines may promote harmonization.(c) 2022 The Authors. Published by Elsevier

Purpose: to determine how ESTRO can collaborate with Radiation Oncology National Societies (NS) according to its mission and values, and to define the new roadmap to strengthen the NS network role in the forthcoming years. Materials and methods: the ESTRO NS committee launched a survey addressed to all European National Societies, available online from June 5th to October 30th 2018. Questions were divided into three main sections: 1. general information about NS; 2. relevant activities (to understand the landscape of each NS context of action); 3. relevant needs (to understand how ESTRO can support the NS). Eighty-nine European NS were invited to participate. Respondents were asked to rank ESTRO milestones in order of importance, indicating the level of priority to their society. Results: a total of 64 out of 89 NS (72%) from 32 European countries completed the questionnaire. The majority of NS ranked “Optimal patient care to cure cancer and to reduce treatment-related toxicity” as the highest level of priority. This aligns well with the ESTRO vision 2030 “Optimal health for all together.” NS also indicated a high need for more consensus guidelines and exchange of best practices, access to high quality accredited education, implementation of the ESTRO School Core Curriculum at the national level, and defining quality indicators and standard in Radiation Oncology, improved communication and increased channelling of information. Conclusion: The results of this survey will be used to strengthen the relations between ESTRO and European NS to promote and develop initiatives to improve cancer care.

Plan evaluation is a key step in the radiotherapy treatment workflow. Central to this step is the assessment of treatment plan quality. Hence, it is important to agree on what we mean by plan quality and to be fully aware of which parameters it depends on. We understand plan quality in radiotherapy as the clinical suitability of the delivered dose distribution that can be realistically expected from a treatment plan. Plan quality is commonly assessed by evaluating the dose distribution calculated by the treatment planning system (TPS). Evaluating the 3D dose distribution is not easy, however; it is hard to fully evaluate its spatial characteristics and we still lack the knowledge for personalising the prediction of the clinical outcome based on individual patient characteristics. This advocates for standardisation and systematic collection of clinical data and outcomes after radiotherapy. Additionally, the calculated dose distribution is not exactly the dose delivered to the patient due to uncertainties in the dose calculation and the treatment delivery, including variations in the patient set-up and anatomy. Consequently, plan quality also depends on the robustness and complexity of the treatment plan. We believe that future work and consensus on the best metrics for quality indices are required. Better tools are needed in TPSs for the evaluation of dose distributions, for the robust evaluation and optimisation of treatment plans, and for controlling and reporting plan complexity. Implementation of such tools and a better understanding of these concepts will facilitate the handling of these characteristics in clinical practice and be helpful to increase the overall quality of treatment plans in radiotherapy. (C) 2020 The Authors. Published by Elsevier B.V.

Background: The IAEA has developed and tested an on-site, end-to-end IMRT/VMAT dosimetry audit methodology for head and neck cases using an anthropomorphic phantom. The audit methodology is described, and the results of the international pilot testing are presented. Material and methods: The audit utilizes a specially designed, commercially available anthropomorphic phantom capable of accommodating a small volume ion chamber (IC) in four locations (three in planning target volumes (PTVs) and one in an organ at risk (OAR)) and a Gafchromic film in a coronal plane for the absorbed dose to water and two-dimensional dose distribution measurements, respectively. The audit consists of a pre-visit and on-site phases. The pre-visit phase is carried out remotely and includes a treatment planning task and a set of computational exercises. The on-site phase aims at comparing the treatment planning system (TPS) calculations with measurements in the anthropomorphic phantom following an end-to-end approach. Two main aspects were tested in the pilot study: feasibility of the planning constraints and the accuracy of IC and film results in comparison with TPS calculations. Treatment plan quality was scored from 0 to 100. Results: Forty-two treatment plans were submitted by 14 institutions from 10 countries, with 79% of them having a plan quality score over 90. Seventeen sets of IC measurement results were collected, and the average measured to calculated dose ratio was 0.988 +/- 0.016 for PTVs and 1.020 +/- 0.029 for OAR. For 13 film measurement results, the average gamma passing rate was 94.1% using criteria of 3%/3 mm, 20% threshold and global gamma. Conclusions: The audit methodology was proved to be feasible and ready to be adopted by national dosimetry audit networks for local impl

With new radiotherapy techniques, treatment delivery is becoming more complex and accordingly, these treatment techniques require dosimetry audits to test advanced aspects of the delivery to ensure best practice and safe patient treatment.This review of novel methodologies for dosimetry audits for advanced radiotherapy techniques includes recent developments and future techniques to be applied in dosimetry audits. Phantom-based methods (i.e. phantom-detector combinations) including independent audit equipment and local measurement equipment as well as phantom-less methods (i.e. portal dosimetry, transmission detectors and log files) are presented and discussed. Methodologies for both conventional linear accelerator (linacs) and new types of delivery units, i.e. Tomotherapy, stereotactic devices and MR-linacs, are reviewed.Novel dosimetry audit techniques such as portal dosimetry or log file evaluation have the potential to allow parallel auditing (i.e. performing an audit at multiple institutions at the same time), automation of data analysis and evaluation of multiple steps of the radiotherapy treatment chain. These methods could also significantly reduce the time needed for audit and increase the information gained. However, to maximise the potential, further development and harmonisation of dosimetry audit techniques are required before these novel methodologies can be applied.

Background and purpose: It is known that intensity-modulated radiotherapy plans that are highly complex might be less accurate in dose calculation and treatment delivery. Multiple complexity metrics have been proposed, but the relationships between them have not been thoroughly investigated. This study investigated these relationships in multi-institutional comparisons of treatment plans, where plans from multiple treatment planning systems (TPSs) are typically evaluated.Materials and methods: A program was developed to compute several complexity indices and provide analysis of dynamic plan parameters. This in-house software was used to analyse plans from a recent multi-institutional audit. Additionally, 100 clinical volumetric modulated arc therapy (VMAT) plans from two institutions using different TPSs were analysed.Results: All plans produced satisfactory pre-treatment verification results and, hence, complexity metrics could not be used to predict plans failing QA. Regarding the relationship among complexity indices, some very strong correlations were found (r > 0.9 with p < 0.01). However, some relevant discrepancies between complexity indices were obtained, even with negative correlation coefficients (r similar to-0.6) which were expected to be positive. These discrepancies could be explained because each complexity index focused on different features of the plan and different TPSs prioritised modulation of different plan parameters.Conclusions: Some complexity indices provided similar information and can be considered equivalent. However, indices that focused on different plan parameters yielded different results and it was unclear which complexity index should be used. Careful consideration should be given to the use of complexity metrics in multi-institutional

Purpose: The aim of this study was to evaluate the suitability of several detectors for the determination of absorbed dose in bone.; Methods: Three types of ultrathin LiF-based thermoluminescent dosimeters (TLDs) two LiF:Mg,Cu,P-based (MCP-Ns and TLD-2000F) and a Li-7-enriched LiF:Mg,Ti-based (MTS-7s)-as well as EBT2 Gafchromic films were used to measure percentage depth-dose distributions (PDDs) in a water-equivalent phantom with a bone-equivalent heterogeneity for 6 and 18 MV and a set of field sizes ranging from 5 x 5 cm(2) to 20 x 20 cm(2). MCP-Ns, TLD-2000F, MTS-7s, and EBT2 have active layers of 50, 20, 50, and 30 mu m, respectively. Monte Carlo (MC) dose calculations (PENELOPE code) were used as the reference and helped to understand the experimental results and to evaluate the potential perturbation of the fluence in bone caused by the presence of the detectors. The energy dependence and linearity of the TLDs' response was evaluated.; Results: TLDs exhibited flat energy responses (within 2.5%) and linearity with dose (within 1.1%) within the range of interest for the selected beams. The results revealed that all considered detectors perturb the electron fluence with respect to the energy inside the bone-equivalent material. MCP-Ns and MTS-7s underestimated the absorbed dose in bone by 4%-5%. EBT2 exhibited comparable accuracy to MTS-7s and MCP-Ns. TLD-2000F was able to determine the dose within 2% accuracy. No dependence on the beam energy or field size was observed. The MC calculations glowed that a 50 mu m thick detector can provide reliable dose estimations in bone regardless of whether it is made of LiF, water or EBT's active layer material.; Conclusions: TLD-2000F was found to be suitable for providing reliable absorbed dose measurements in the presence of bone for high-energy x-ray beams. 2014 American Association of Physicists in Medicine., Postprint (published version)