A pre-treatment quality assurance survey on 384 patients treated with helical intensity-modulated radiotherapy

Bresciani, S.; Miranti, A.; Dia, A. Di; Maggio, A.; Bracco, Christian; Poli, Matteo Umberto; Spirito, Davide Di; Gabriele, P.; Stasi, M.

doi:10.1016/j.radonc.2015.12.021

Cited by 9 publications

(12 citation statements)

References 9 publications

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“…TPS dose calculation (beam modeling, MLC modeling, commissioning inaccuracies) and MLC performance are also some potential sources of errors.The impact of HT plan parameters on the pretreatment QA results has already been investigated by other authors 2,8,9. Westerly et al,2 for instance, found that plans with a mean LOT below 100 ms, that is, using predominantly small leaf open times, were more likely to present significant deviations (>3%) between the calculated and the measured doses, in an analysis of six plans treated in a Tomotherapy Hi-Art II system.…”

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confidence: 93%

“…2,7 More comprehensive studies for different treatment sites, including a wider set of TPS reported parameters, such as the couch travel, couch speed, number of gantry rotations, gantry period and treatment time, have been carried out. 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.…”

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confidence: 99%

“…Westerly et al,2 for instance, found that plans with a mean LOT below 100 ms, that is, using predominantly small leaf open times, were more likely to present significant deviations (>3%) between the calculated and the measured doses, in an analysis of six plans treated in a Tomotherapy Hi-Art II system. Bresciani et al8 have taken a pool of 384 HT plans to investigate if there were any treatment sites and/or plan parameters more likely to lead to poorer verification results. A wide variety of treatment sites were included, such as gynecological, head and neck, breast, lung, rectum, but no significant differences were noticed.…”

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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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confidence: 93%

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confidence: 99%

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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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“…The results here reportedly outperformed those obtained with different versions of tomotherapy machines and the same 3D dosimeter (ArcCHECK™) in terms of GP%. We measured systematically higher mean values with respect to Bresciani [7], Binny [9] and Yue [10]: 99.2% (SD 1.3%) vs 96.1% (SD 4.4%), 95.9%(SD 2.9%) and 97.5% (SD 2.7%), respectively.…”

Section: Discussionmentioning

confidence: 68%

“…In this work, we assessed the performances of the TomoTherapy® platform coupled with a new dedicated TPS in terms of the gamma index passing rate measured with a 3D dosimeter, extending the analysis of previous works on earlier versions of TomoTherapy® and associated TPS [7,8]. The entire scope of work was performed following AAPM TG-218 recommendations.…”

Section: Discussionmentioning

confidence: 99%

Analysis of Clinical Patient-Specific Pre-Treatment Quality Assurance with the New Helical TomoTherapy® Platform, following the AAPM TG-218 Report

Fusella

Cavinato

Germani

et al. 2021

Preprint

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Purpose: This study presents patient-specific quality assurance (QA) results from the first 395 clinical cases for the new helical TomoTherapy® platform (Radixact) coupled with dedicated Precision TPS.Methods: The passing rate of the Gamma Index (GP%) of 395 helical QA of patient-specific Tomotherapy, acquired with ArcCHECK, is presented, analysed and correlated to various parameters of the plan. Following TG-218 recommendations, the clinic specific action limit (ALcs) and tolerance limit (TLcs) were calculated for our clinic and monitored during the analysed period.Results: the mean values (± 1 standard deviation) of GP% (3% / 2mm) (both global and local normalization) are: 97.6% and 90.9%, respectively. The proposed ALcs and TLcs, after a period of two years’ process monitoring are 89.4% and 91.1% respectively.Conclusions: The phantom measurements closely match the planned dose distributions, demonstrating that the calculation accuracy of the new Precision TPS and the delivery accuracy of the Radixact unit are adequate, with respect to international guidelines and reports. Furthermore, a first correlation with the planning parameters was made. Action and tolerance limits have been set for the new Radixact Linac.

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Quantitative assessment of helical tomotherapy plans complexity

Cavinato

Fusella

Paiusco

et al. 2022

J Applied Clin Med Phys

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Purpose An unnecessary amount of complexity in radiotherapy plans affects the efficiency of the treatments, increasing the uncertainty of dose deposition and its susceptibility to anatomical changes or setup errors. To date, tools for quantitatively assessing the complexity of tomotherapy plans are still limited. In this study, new metrics were developed to characterize different aspects of helical tomotherapy (HT) plans, and their actual effectiveness was investigated. Methods The complexity of 464 HT plans delivered on a Radixact platform was evaluated. A new set of metrics was devised to assess beam geometry, leaf opening time (LOT) variability, and modulation over space and time. Sixty‐five complexity metrics were extracted from the dataset using the newly in‐house developed software library TCoMX: 29 metrics already proposed in the literature and 36 newly developed metrics. Their reciprocal relation is discussed. Their effectiveness was evaluated through correlation analyses with patient‐specific quality assurance (PSQA) results. Results An inverse linear relation was found between the average number of closed leaves and the average number of MLC openings and closures as well as between the choice of the modulation factor and the discontinuity of the field, suggesting some intrinsic link between the LOT distribution and the geometrical complexity of the MLC openings. The newly proposed metrics were at least as correlated as the existing ones to the PSQA results. Metrics describing the geometrical complexity of the MLC openings showed the strongest connection to the PSQA results. Significant correlations were found between at least one of the new metrics and the γ index passing rate for six out of seven groups of plans considered. Conclusion The new metrics proposed were shown to be effective to characterize more comprehensively the complexity of HT plans. A software library for their automatic extraction is described and made available.

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A pre-treatment quality assurance survey on 384 patients treated with helical intensity-modulated radiotherapy

Cited by 9 publications

References 9 publications

On the complexity of helical tomotherapy treatment plans

On the complexity of helical tomotherapy treatment plans

Analysis of Clinical Patient-Specific Pre-Treatment Quality Assurance with the New Helical TomoTherapy® Platform, following the AAPM TG-218 Report

Quantitative assessment of helical tomotherapy plans complexity

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