Clinical implementations of 4D pencil beam scanned particle therapy: Report on the 4D treatment planning workshop 2016 and 2017

Trnková, Petra; Knäusl, B.; Actis, O.; Bert, Christoph; Biegun, A.; Boehlen, T.T.; Furtado, Hugo; McClelland, Jamie R.; Mori, Shinichiro; Rinaldi, I.; Ruciński, Antoni; Knopf, Antje

doi:10.1016/j.ejmp.2018.10.002

Cited by 35 publications

(31 citation statements)

References 127 publications

(120 reference statements)

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“…Second, we did not consider the intrafractional changes, such as tumor respiratory motion during treatment, which also affected the dose distribution [25]. A 4D treatment plan based on daily 4DCT or real-time tumor tracking is a promising method to reduce these uncertainties, which have been recently discussed in particle RT [26][27][28]; moreover, the DIR method has its own uncertainties, although the dose warping errors are generally less than 3% [29,30]. Furthermore, a larger margin may be required to compensate for the interfractional deviations in BM while employing a scanning pencil beam technology; consequently, the effects induced by the changes in the WEL may be greater than those observed in the present study.…”

Section: Discussionmentioning

confidence: 99%

Dose assessment for patients with stage I non-small cell lung cancer receiving passive scattering carbon-ion radiotherapy using daily computed tomographic images: A prospective study

Kubota

Kubo

et al. 2020

Radiotherapy and Oncology

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a b s t r a c tBackground and purpose: This study aimed to assess dose distributions for stage I non-small cell lung cancer (NSCLC) with passive scattering carbon-ion radiotherapy (C-ion RT) using daily computed tomography (CT) images. Materials and methods: We enrolled 10 patients with stage I NSCLC and acquired a total of 40 prefractional CT image series under the same settings as the planning CT images. These CT images were registered with planning CT images for dose evaluation using both bone matching (BM) and tumor matching (TM). Using deformable image registration, we generated accumulated doses. Moreover, the volumetric dose parameters were compared in terms of tumor coverage and lung exposure and statistical analyses were performed. Results: Overall, 25% of 40 fractional dose distributions were unacceptable with BM, compared with 2.5% with TM (P < 0.001). Using BM, three patients' accumulated dose distributions were unacceptable; however, all were satisfactory with TM (P < 0.001). No differences were observed in water-equivalent path length (WEL). The required margins in patients with poor dose distribution were 5.9 and 4.4 mm for BM and TM, respectively. Conclusions: This study establishes that CT image-based TM is robust compared with conventional BM for both daily and accumulated dose distributions. The effects of changes in WEL seem to be limited. Hence, daily CT alignment is recommended for patients with stage I NSCLC receiving C-ion RT. Ó 2020 The Author(s). Published by Elsevier B.V. Radiotherapy and Oncology 144 (2020) 224-230 This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).For over two decades now, carbon-ion radiotherapy (C-ion RT) has been used for the treatment of early-stage non-small cell lung cancer (NSCLC) [1]. Compared with stereotactic body radiotherapy, which has exhibited promising outcomes for inoperable earlystage NSCLC [2], C-ion RT facilitates delivering a higher dose to the target with extremely low lung toxicity because of its fine dose concentration [3,4]. These advantages make C-ion RT a good treatment option for patients with NSCLC. However, C-ion RT is highly sensitive to anatomical changes that merit focus, especially for mobile tumors. Dose degradation caused by tumor movement is regarded as one of the potential factors for local recurrence in patients with NSCLC [5,6].The gated computed tomography (CT) and four-dimensional CT (4DCT) have been routinely used to manage the tumor motion [7]. The effects of respiratory motion are limited when an appropriate internal margin is applied [8]. However, the interfractional anatomical changes are the main source of the dose degradation in C-ion RT. Most published studies focus on their effects on the particle dose in a conventional treatment schedule (5-6 weeks) for patients with lung cancer using limited CT scans or 2D imaging technology [6,[9][10][11]. However, very few studies report hypofractionated C-ion RT. Recently, tumor displacement and changes in water-equival...

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Section: Discussionmentioning

confidence: 99%

Dose assessment for patients with stage I non-small cell lung cancer receiving passive scattering carbon-ion radiotherapy using daily computed tomographic images: A prospective study

Kubota

Kubo

et al. 2020

Radiotherapy and Oncology

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“…The XCAT phantom uses diaphragm position to calculate its deformations, but many systems for breathing monitoring use a surrogate signal, such as chest wall deflection. Although the correlation of the (external) surrogate and tumor/diaphragm motion may vary from patient to patient and even fraction to fraction, 31 the XCAT phantom allows a convenient way to analyze, for example, Medical Physics, 0 (0), xxxx the impact of location of an external surrogate for an average patient.…”

Section: Discussionmentioning

confidence: 99%

Technical Note: Investigating interplay effects in pencil beam scanning proton therapy with a 4D XCAT phantom within the RayStation treatment planning system

et al. 2021

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Pencil beam scanning (PBS) for moving targets is known to be impacted by interplay effects. Four-dimensional computed tomography (4DCT)-based motion evaluation is crucial for understanding interplay and developing mitigation strategies. Availability of high-quality 4DCTs with variable breathing traces is limited. Purpose of this work is the development of a framework for interplay analysis using 4D-XCAT phantoms in conjunction with time-resolved irradiation patterns in a commercial treatment planning system (TPS). Four-dimensional dynamically accumulated dose distributions (4DDDs) are simulated in an in-silico study for a PBS liver treatment. Methods: An XCAT phantom with 50 phases, varying linearly in amplitude each by 1 mm, was combined with the RayStation TPS (7.99.10). Deformable registration was used with time-resolved dose calculation, mapping XCAT phases to motion signals. To illustrate the applicability of the method a two-field liver irradiation plan was used. A variety sin 4 type motion signals, varying in amplitude (1-20 mm), period (1.6-5.2 s) and phase (0-2π) were applied. Either single variable variations or random combinations were selected. The interplay effect within a clinical target (5 cm diameter) was characterized in terms of homogeneity index (HI5), with and without five paintings. In total 2092 scenarios were analyzed within RayStation. Results: A framework is presented for interplay research, allowing for flexibility in determining motion management techniques, increasing reproducibility, and enabling comparisons of different methods. A case study showed the interplay effect was correlated with amplitude and strongly affected by the starting phase, leading to large variance. The average of all scenarios (single fraction) resulted in HI5 of 0.31 (AE0.11), while introduction of five times layered repainting reduced this to 0.11(AE0.03). Conclusion: The developed framework, which uses the XCAT phantom and RayStation, allows detailed analysis of motion in context of PBS with comparable results to clinical cases. Flexibility in

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“…However, in the abdominal region, organ motion significantly affects treatment quality and can cause severe consequences in terms of accuracy in dose delivery. Thus, several strategies were proposed to mitigate respiratory motion or correlate the patient respiratory pattern to treatment planning and delivery …”

Section: Introductionmentioning

confidence: 99%

“…Thus, several strategies were proposed to mitigate respiratory motion or correlate the patient respiratory pattern to treatment planning and delivery. [8][9][10][11] For respiratory moving targets, the motion information is integrated in the treatment planning process by means of respiratory-correlated four-dimensional (4D) imaging, with 4D computed tomography (4DCT) being the current clinical standard. 12 The main limitation of using 4DCT as imaging modality for treatment planning is that this technique depicts an "average" respiratory cycle, being representative of the imaged anatomy only within the time interval of the imaging acquisition.…”

Section: Introductionmentioning

confidence: 99%

Virtual 4DCT from 4DMRI for the management of respiratory motion in carbon ion therapy of abdominal tumors

et al. 2020

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Purpose To evaluate a method for generating virtual four‐dimensional computed tomography (4DCT) from four‐dimensional magnetic resonance imaging (4DMRI) data in carbon ion radiotherapy with pencil beam scanning for abdominal tumors. Methods Deformable image registration is used to: (a) register each respiratory phase of the 4DMRI to the end‐exhale MRI; (b) register the reference end‐exhale CT to the end‐exhale MRI volume; (c) generate the virtual 4DCT by warping the registered CT according to the obtained deformation fields. A respiratory‐gated carbon ion treatment plan is optimized on the planning 4DCT and the corresponding dose distribution is recalculated on the virtual 4DCT. The method was validated on a digital anthropomorphic phantom and tested on eight patients (18 acquisitions). For the phantom, a ground truth dataset was available to assess the method performances from the geometrical and dosimetric standpoints. For the patients, the virtual 4DCT was compared with the planning 4DCT. Results In the phantom, the method exhibits a geometrical accuracy within the voxel size and Dose Volume Histograms deviations up to 3.3% for target V95% (mean dose difference ≤ 0.2% of the prescription dose, gamma pass rate > 98%). For patients, the virtual and the planning 4DCTs show good agreement at end‐exhale (3% median D95% difference), whereas other respiratory phases exhibit moderate motion variability with consequent dose discrepancies, confirming the need for motion mitigation strategies during treatment. Conclusions The virtual 4DCT approach is feasible to evaluate treatment plan robustness against intra‐ and interfraction motion in carbon ion therapy delivered at the abdominal site.

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Clinical implementations of 4D pencil beam scanned particle therapy: Report on the 4D treatment planning workshop 2016 and 2017

Cited by 35 publications

References 127 publications

Dose assessment for patients with stage I non-small cell lung cancer receiving passive scattering carbon-ion radiotherapy using daily computed tomographic images: A prospective study

Dose assessment for patients with stage I non-small cell lung cancer receiving passive scattering carbon-ion radiotherapy using daily computed tomographic images: A prospective study

Technical Note: Investigating interplay effects in pencil beam scanning proton therapy with a 4D XCAT phantom within the RayStation treatment planning system

Virtual 4DCT from 4DMRI for the management of respiratory motion in carbon ion therapy of abdominal tumors

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