Investigation of a novel algorithm for true 4D-VMAT planning with comparison to tracked, gated and static delivery

Chin, E; Otto, Karl F.

doi:10.1118/1.3578608

Cited by 30 publications

(30 citation statements)

References 56 publications

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“…Our findings for the lung patient are consistent with their findings, which showed only slight reductions of dose to avoidance volumes for lung and liver patients using 4D-optimized photon beam tracking instead of photon beam gating. Similar to Chin and Otto (2011), we observed, in a phantom study, 4D optimization has a large ability to spare an avoidance volume near a moving target. In comparison with the approach of Graeff et al (in press), our method was similar in how we calculated the 4D dose contribution to each voxel from each ion pencil beam for each motion state and included these in 4D optimization.…”

Section: Discussionsupporting

confidence: 80%

“…Nohadani et al (2010) reported another 4D optimization approach for photon therapy that improved dose coverage compared to beam gating for lung cancer patients and reduced dose to healthy lung and was also more robust to irregular breathing than beam gating. Chin and Otto (2011) further demonstrated in phantom studies that 4D optimization can be applied to volumetric modulated arc therapy to spare avoidance volumes near a moving target. These studies suggest that the added degree of freedom, namely time, facilitates the optimization process and yields improved target dose coverage and to spare avoidance volumes near a moving target.…”

Section: Introductionmentioning

confidence: 96%

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4D optimization of scanned ion beam tracking therapy for moving tumors

et al. 2014

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Motion mitigation strategies are needed to fully realize the theoretical advantages of scanned ion beam therapy for patients with moving tumors. The purpose of this study was to determine whether a new four-dimensional (4D) optimization approach for scanned-ion-beam tracking could reduce dose to avoidance volumes near a moving target while maintaining target dose coverage, compared to an existing 3D-optimized beam tracking approach. We tested these approaches computationally using a simple 4D geometrical phantom and a complex anatomic phantom, that is, a 4D computed tomogram of the thorax of a lung cancer patient. We also validated our findings using measurements of carbon-ion beams with a motorized film phantom. Relative to 3D-optimized beam tracking, 4D-optimized beam tracking reduced the maximum predicted dose to avoidance volumes by 53% in the simple phantom and by 13% in the thorax phantom. 4D-optimized beam tracking provided similar target dose homogeneity in the simple phantom (standard deviation of target dose was 0.4% versus 0.3%) and dramatically superior homogeneity in the thorax phantom (D5-D95 was 1.9% versus 38.7%). Measurements demonstrated that delivery of 4D-optimized beam tracking was technically feasible and confirmed a 42% decrease in maximum film exposure in the avoidance region compared with 3D-optimized beam tracking. In conclusion, we found that 4D-optimized beam tracking can reduce the maximum dose to avoidance volumes near a moving target while maintaining target dose coverage, compared with 3D-optimized beam tracking.

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Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 96%

4D optimization of scanned ion beam tracking therapy for moving tumors

et al. 2014

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“…These effects additionally could be reduced by gating the treatment to a steady tumor position or tracking the moving tumor. Planning studies [14,15,8,16] and phantom studies [17,18] for comparisons between motion-management techniques have been performed previously. Planning studies are generally based on four-dimensional computed tomography data sets (4DCT), which provide patient-specific data for the dose calculation, but neglect actual capabilities of the delivery systems and are prone to motion artifacts [19].…”

Section: Introductionmentioning

confidence: 99%

Respiratory motion-management in stereotactic body radiation therapy for lung cancer – A dosimetric comparison in an anthropomorphic lung phantom (LuCa)

Ehrbar

Perrin

Peroni

et al. 2016

Radiotherapy and Oncology

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BACKGROUND AND PURPOSE The objective of this study was to compare the latest respiratory motion-management strategies, namely the internal-target-volume (ITV) concept, the midventilation (MidV) principle, respiratory gating and dynamic couch tracking. MATERIALS AND METH-ODS An anthropomorphic, deformable and dynamic lung phantom was used for the dosimetric validation of these techniques. Stereotactic treatments were adapted to match the techniques and five distinct respiration patterns, and delivered to the phantom while radiographic film measurements were taken inside the tumor. To report on tumor coverage, these dose distributions were used to calculate mean doses (Dmean), changes in homogeneity indices (ΔH2-98), gamma agreement, and areas covered by the planned minimum dose (A>Dmin). RESULTS All techniques achieved good tumor coverage (A>Dmin>99.0%) and minor changes in Dmean (±3.2%). Gating and tracking strategies showed superior results in gamma agreement and ΔH2-98 compared to ITV and MidV concepts, which seem to be more influenced by the interplay and the gradient effect. For lung, heart and spinal cord, significant dose differences between the four techniques were found (p<0.05), with lowest doses for gating and tracking strategies. CONCLUSION Active motion-management techniques, such as gating or tracking, showed superior tumor dose coverage and better organ dose sparing than the passive techniques based on tumor margins. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1016/j.radonc.2016.10.011 This article is protected by copyright. All rights reserved. AbstractBackground and Purpose: The objective of this study was to compare the latest respiratory motion-management strategies, namely the internal-target-volume (ITV) concept, the mid-ventilation (MidV) principle, respiratory gating and dynamic couch tracking. Materials and Methods: An anthropomorphic, deformable and dynamic lung phantom was used for the dosimetric validation of these techniques. Stereotactic treatments were adapted to match the techniques and five distinct respiration patterns, and delivered to the phantom while radiographic film measurements were taken inside the tumor. To report on tumor coverage, these dose distributions were used to calculate mean doses (Dmean), changes in homogeneity indices (ΔH 2-98 ), gamma agreement, and areas covered by the planned minimum dose (A >Dmin ).Results: All techniques achieved good tumor coverage (A >Dmin >99.0%) and minor changes in D mean (±3.2%). Gating and tracking strategies showed superior results in gamma agreement and ΔH 2-98 compared to ITV and MidV concepts, which seem to be more influenced by the interplay and the gradient effect. For lung, heart and spinal cord, significant dose differences between the four techniques were found (p<0.05), with l...

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“…Such evidence tells us that if the relative distance of the PTV and OAR is considered when the apertures are morphed, OAR sparing may be improved. By using rigidly moving phantoms, Chin et al has studied and demonstrated the importance of considering the relative distance of PTV and OAR in 4D planning (Chin et al 2011). However, similar study has not been conducted for real patients with 4D CT, therefore, should be pending for the future.…”

Section: Discussionmentioning

confidence: 99%

“…The pattern of rigid motion simplified the registration matrix, and therefore the 4D-dose calculation. Another approach was proposed by Chin et al , which extended the Otto’s algorithm for 3D-IMAT to be used for 4D-IMAT planning (Otto 2008, Chin et al 2011). In their 4D algorithm, time-correlated beam samples were progressively added during optimization throughout the full range of a single arc.…”

Section: Introductionmentioning

confidence: 99%

Planning 4D intensity-modulated arc therapy for tumor tracking with a multileaf collimator

et al. 2017

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This study introduces a practical four-dimensional (4D) planning scheme of IMAT using 4D computed tomography (4D CT) for planning tumor tracking with dynamic multileaf beam collimation. We assume that patients can breathe regularly, i.e., the same way as during 4D CT with an unchanged period and amplitude, and that the start of 4D-IMAT delivery can be synchronized with a designated respiratory phase. Each control point of the IMAT-delivery process can be associated with an image set of 4D CT at a specified respiratory phase. Target is contoured at each respiratory phase without a motion-induced margin. A 3D-IMAT plan is first optimized on a reference-phase image set of 4D CT. Then, based on the projections of the planning target volume (PTV) in the beam’s eye view (BEV) at different respiratory phases, a 4D-IMAT plan is generated by transforming the segments of the optimized 3D plan by using a direct aperture deformation (DAD) method. Compensation for both translational and deformable tumor motion is accomplished, and the smooth delivery of the transformed plan is ensured by forcing connectivity between adjacent angles (control points). It is envisioned that the resultant plans can be delivered accurately using the dose rate regulated tracking (DRRT) method which handles breathing irregularities (Yi et al 2008). This planning process is straightforward and only adds a small step to current clinical 3D planning practice. Our 4D planning scheme was tested on three cases to evaluate dosimetric benefits. The created 4D-IMAT plans showed similar dose distributions as compared with the 3D-IMAT plans on a single static phase, indicating that our method is capable of eliminating the dosimetric effects of breathing induced target motion. Compared to the 3D-IMAT plans with large treatment margins encompassing respiratory motion, our 4D-IMAT plans reduced radiation doses to surrounding normal organs and tissues.

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Investigation of a novel algorithm for true 4D-VMAT planning with comparison to tracked, gated and static delivery

Abstract: Our investigation demonstrated that the 4D-VMAT system has the potential to improve radiation therapy of periodically moving tumors over 3D-VMAT, gating or tracking methods.

Cited by 30 publications

References 56 publications

4D optimization of scanned ion beam tracking therapy for moving tumors

4D optimization of scanned ion beam tracking therapy for moving tumors

Respiratory motion-management in stereotactic body radiation therapy for lung cancer – A dosimetric comparison in an anthropomorphic lung phantom (LuCa)

Planning 4D intensity-modulated arc therapy for tumor tracking with a multileaf collimator

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