IMRT national audit in Portugal

Santos, T.; Lopes, Maria do Carmo; Gershkevitsh, E.; Vinagre, F.L.R.; Faria, David; Carita, L.; Pontes, M.; Vieira, Sandra; Poli, E.; Faustino, S.; Ribeiro, F.A.; Trindade, Mauro; Ponte, Fernanda; Marcelino, Carlos; Batista, Cláudio; Oliveira, Susana Cristina; Figueira, R.C.S.; Lencart, Joana; Diaz, Ester Gallego; Jacob, K.; Brás, Susana; Pirraco, R.; Iżewska, J.

doi:10.1016/j.ejmp.2019.08.013

Cited by 6 publications

(4 citation statements)

References 34 publications

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“…To summarize the information given by all complexity metrics, a global plan complexity score (nPCS) was calculated, following the methodology proposed by Santos et al 25 in the context of a national IMRT audit. 28 The nPCS combines the multiple metrics into a single numerical score, allowing for the comparison of the relative complexity of the entire set of plans. Based on the nPCS values, the head and neck plans confirmed to be the most complex, followed by the prostate and the stereotactic brain ones.…”

Section: Discussionmentioning

confidence: 99%

“…8,9 Bresciani et al, 8 using 384 HT plans of multiple treatment sites, found no strong correlations between some of these factors and the results of pretreatment QA verification. Binny et al 9 have used multiple statistical process control methods on a set of head and neck (28), pelvic (19) and brain (23) plans, to define lower and upper limits for planning parameters, like the modulation factor, gantry period, and couch speed, based on acceptable pretreatment QA results. The established ranges were specific to each treatment site and contributed to improve the treatment efficiency at their institution.…”

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confidence: 99%

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On the complexity of helical tomotherapy treatment plans

Santos

Ventura

Mateus

et al. 2020

J Applied Clin Med Phys

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Purpose Multiple metrics are proposed to characterize and compare the complexity of helical tomotherapy (HT) plans created for different treatment sites. Methods A cohort composed of 208 HT plans from head and neck (105), prostate (51) and brain (52) tumor sites was considered. For each plan, 14 complexity metrics were calculated. Those metrics evaluate the percentage of leaves with small opening times or approaching the projection duration, the percentage of closed leaves, the amount of tongue‐and‐groove effect, and the overall modulation of the planned sinogram. To enable data visualization, an approach based on principal component analysis was followed to reduce the dataset dimensionality. This allowed the calculation of a global plan complexity score. The correlation between plan complexity and pretreatment verification results using the Spearman’s rank correlation coefficients was investigated. Results According to the global score, the most complex plans were the head and neck tumor cases, followed by the prostate and brain lesions irradiated with stereotactic technique. For almost all individual metrics, head and neck plans confirmed to be the plans with the highest complexity. Nevertheless, prostate cases had the highest percentage of leaves with an opening time approaching the projection duration, whereas the stereotactic brain plans had the highest percentage of closed leaves per projection. Significant correlations between some of the metrics and the pretreatment verification results were identified for the stereotactic brain group. Conclusions The proposed metrics and the global score demonstrated to be useful to characterize and quantify the complexity of HT plans of different treatment sites. The reported differences inter‐ and intra‐group may be valuable to guide the planning process aiming at reducing uncertainties and harmonize planning strategies.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

On the complexity of helical tomotherapy treatment plans

Santos

Ventura

Mateus

et al. 2020

J Applied Clin Med Phys

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“…Although, on average, IC results were in agreement, systematic shifts were noted for the IC_PTV_7000 and IC_SpinalCord points, which also contributed to the establishment of the tolerance levels. It is expected that they will be further verified in future national studies and might be adjusted if necessary [31].…”

Section: Discussionmentioning

confidence: 99%

IAEA methodology for on-site end-to-end IMRT/VMAT audits: an international pilot study

et al. 2019

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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 implementation.

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“…To fulfill the QA needs of advanced radiotherapy treatment techniques a higher level of radiotherapy postal dosimetry audit is required, moving the IAEA to adapt its TLD postal dose audit to include the non-reference conditions that focus on greater targeted radiation. As herein, some countries have established their own national dose audit, for both reference and non-reference conditions, use being made of various passive dosimeters [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%