A multi-center output factor intercomparison to uncover systematic inaccuracies in small field dosimetry

Clemente, Stefania; Masi, Laura; Fiandra, C.; Cagni, E.; Villaggi, E.; Esposito, Marco; Giglioli, F.R.; Marino, C.; Strigari, Lidia; Garibaldi, Cristina; Stasi, M.; Mancosu, P.; Russo, S.

doi:10.1016/j.phro.2018.03.007

Cited by 10 publications

(4 citation statements)

References 21 publications

(46 reference statements)

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“…Twenty‐four papers/reviews/letters have been published on top 50% ranking Radiation Oncology journals in 2014–2019 period, 18–40 with authors list selected according to Vancouver recommendations. In detail, 15 full papers 19–23,28–32,34–36,38,40 . 5 reviews, 18,27,33,37,41 1 editorial, 25 and 3 letters to the editor 24,26,39 were published.…”

Section: Resultsmentioning

confidence: 99%

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Lean Thinking to manage a national working group on physics aspects of Stereotactic Body Radiation Therapy

Mancosu

Russo

Antonucci³

et al. 2021

Medical Physics

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To report how the adoption of a Lean Thinking mindset in the management of a national working group (WG) on the physics of stereotactic body radiation therapy (SBRT) contributed to achieve SBRT standardization objectives. Methods: Vision for the WG has been established as fragmentation reduction and process harmonization enhancement in SBRT for Italian centers. Two main research themes of the technical aspects of SBRT emerged as areas with major standardization improvement needs, small field dosimetry and SBRT planning comparisons, to be investigated through multi-institutional studies. The management of the WG leveraged on the Lean concept of fostering self-organization in a non-hierarchical environment. Four progressive involvement levels were defined for each study. No specific "scientific" preexperience was required to propose and coordinate a project, just requiring a voluntary commitment. People engagement was measured in terms of number of published articles. The standardization goals have been conducted through a simplified "5S" (Sort, Set in Order, Shine, Standardize, and Sustain) methodology, first considering a phase of awareness (the first three "S"), then identifying and implementing standardization actions (the last two "S"). Results: Since the beginning, 157 medical physicists joined the AIFM/SBRT-WG. Twenty-four papers/reviews/letters have been published in the period 2014-2019 on major radiation oncology journals, authored by >100 physicists (>50% working in small hospitals). Six over 12 first authors worked in peripheral/small hospitals, with no prior publication as first author. These studies contributed to the awareness and standardization phases for both small-field dosimetry and planning. In particular, errors in small-field measurements in 8% of centers were detected thanks to a generalized output factor curve in function of the effective field size created by averaging data available from different Linacs. Furthermore, planner's experience in SBRT was correlated with dosimetric parameters in the awareness phase; while sharing median dose volume histograms (DVHs) reduced variability among centers while keeping the same level of plan complexity. Finally, all the dosimetric parameters statistically significant to the planner experience during the awareness phase, were no longer significantly different in the standardization phase. Conclusions: The experience of our SBRT-WG has shown how a Lean Thinking mindset could foster the SBRT procedure standardization and spread the physics of SBRT knowledge, enhancing personal growth. Our expectation is to inspire other scientific societies that have to deal with fragmented contexts or pursue processes harmonization through Lean principles.

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Section: Resultsmentioning

confidence: 99%

“…In detail, 15 full papers. [19][20][21][22][23][28][29][30][31][32][34][35][36]38,40 5 reviews, 18,27,33,37,41 1 editorial, 25 and 3 letters to the editor 24,26,39 were published. A total of more than 100 medical physicists were authors of at least one article, showing high level of members' engagement.…”

Section: B Engagement Metricsmentioning

confidence: 99%

Lean Thinking to manage a national working group on physics aspects of Stereotactic Body Radiation Therapy

Mancosu

Russo

Antonucci³

et al. 2021

Medical Physics

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“…This has been recently addressed by the publication of the IAEA code of practice [41] but the accurate modelling of small fields and how the correct detector is used to collect the commissioning data is still challenging. Several groups [11,12,21] conducted national and multi-national audits respectively, of calculated small field output factors by comparing with standardised data published by the IROC-Houston QA center at MD Anderson [22,23,42] and found that not all centres were modelling these fields well. The audits found that the deviations increased with decreasing field size and the treatment planning system commonly overestimated in comparison with the reference data.…”

Section: Advanced Techniquesmentioning

confidence: 99%

“…Dosimetry audit is a key component in quality management programmes in radiotherapy, playing an important role in the safe implementation of new treatment modalities and techniques [1][2][3][4]. National and large scale audits provide data which can help to create, sustain and increase standards as well as have the potential to identify issues which may cause harm to patients, thus improving both quality and safety [1,[4][5][6][7][8][9][10][11][12][13]. They can also help to reduce variability in dose delivered to the patient both nationally, internationally and within multi-institutional trials [3,[13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

The role of dosimetry audit in achieving high quality radiotherapy

Clark

Jornet

Muren

2018

Physics and Imaging in Radiation Oncology

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A multi-detector comparison to determine convergence of measured relative output factors for small field dosimetry

Chi,

Toan,

Hill

2023

Phys Eng Sci Med

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Purpose: Good clinical practice in small field dosimetry relies on using multiple detectors for the determination of relative output factors (ROFs). The TRS-483 Code of Practice (CoP) provides recommended output correction factors, k, for a range of detectors and beam energies as used in small field dosimetry. In this work, the convergence of the ROFs for 6MV x-ray beams with and without flattening-filters were investigated under a different combinations of beam collimation and published detector correction factors.Method: Three IBA detectors SFD, PFD and CC04 were used to measure ROFs on a TrueBeam STx linear accelerator with small fields collimated by the high definition MLC which has 2.5 mm and 5.0 mm wide leaves. Two configurations were used for the collimators being 1) fixed-jaws at 10 × 10 cm 2 and 2) with a 2 mm offset from the MLC edge, in line with the recommended geometry from IROC-H as part of their auditing program and published dataset. The k factors for the three detectors were taken from the TRS483 CoP and other published works. Results:The standard deviation in measured ROFs between detectors under 6MV-WFF beam are 1.4% and 1.9% while these under 6MV-FFF beam are 2.3% and 2.4% in MLC field with fixed-jaw and with 2 mm jaws-offset, respectively. The relative difference in averaged ROFs of three reference detectors from corresponding IROC-H dataset are 2.0% and 3.1% under 6MV-WFF beam while they are 2.4% and 3.2% under 6MV-FFF beam at the smallest available field size 2 × 2 cm 2 . For smaller field sizes, the uncertainty in averaged ROFs of three reference detectors from corresponding results of from 2 mm jaws-offset setting by Akino and Dufreneix showed the largest difference are 6.6% and 6.2% under 6MV-WFF beam while they are 3.4% and 3.6% under 6MV-WFF beam at smallest field size 0.5 × 0.5 cm 2 . Conclusion:The corresponding datasets provided by TRS-483 and IROC-H are generic and may not statistically large enough with 6MV-FFF and also MLC field with 2 mm jaws-offset setting, so that clinical users should use at least three different types of small field detector in measurements. The IROC-H dataset is not available for field size smaller than 2 × 2 cm 2 so that user should carefully check with other publications with the same setting.

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A multi-center output factor intercomparison to uncover systematic inaccuracies in small field dosimetry

Cited by 10 publications

References 21 publications

Lean Thinking to manage a national working group on physics aspects of Stereotactic Body Radiation Therapy

Lean Thinking to manage a national working group on physics aspects of Stereotactic Body Radiation Therapy

The role of dosimetry audit in achieving high quality radiotherapy

A multi-detector comparison to determine convergence of measured relative output factors for small field dosimetry

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