Electromagnetic guided couch and multileaf collimator tracking on a TrueBeam accelerator

Hansen, Rune; Ravkilde, T.; Worm, E.; Toftegaard, J.; Grau, Cai; Maček, Kristijan; Poulsen, Per Rugaard

doi:10.1118/1.4946815

Cited by 42 publications

(75 citation statements)

References 21 publications

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“…The evaluation over the whole measurement volume showed very high 2%/2 mm GAI with a mean of 99.7% with tracking, compared to 81.8% without tracking. Slightly better results were found by Hansen et al with a 2%/2 mm gamma failure rate of 0.0% and 0.1% for couch tracking of a low‐ and a high‐modulated prostate plan with a similar measurement setup. The excellent outcome of their study perhaps originated in the employed dose concept.…”

Section: Discussionmentioning

confidence: 71%

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Validation of dynamic treatment-couch tracking for prostate SBRT

et al. 2017

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Section: Discussionmentioning

confidence: 71%

“…This gives an approximation on the error for the dose measurements. Hansen et al also reported reduced measurement reproducibility. They found for the 1%/1 mm gamma failure rate a mean of 1.8% under Calypso operation, versus 0.0% failure without operation.…”

Section: Discussionmentioning

confidence: 99%

Validation of dynamic treatment-couch tracking for prostate SBRT

et al. 2017

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“…Additionally, the couch motion is limited by acceleration speed, and therefore might have problems mitigating steep motion gradients. Hansen et al [22] reported RMSE for the use of a fast Kalman filter, as it was applied in this work. A reduction in RMSE from 2.45 mm down to 0.85 mm was observed for lung motion curves when couch tracking was applied.…”

Section: Discussionmentioning

confidence: 99%

“…For gating and tracking treatments, Calypso transponders (Varian Medical System, Palo Alto, CA) were inserted into the tumor, monitoring its motion in real-time. The tracking system latency, which includes the time needed for position detection, signal processing and final repositioning of the couch, was reported for the same couch tracking system to be in the range of 187 to 246 ms for sine motion patterns with periods from 8 to 2 seconds, if no motion prediction algorithm is used [22]. To mitigate the influence of the system latency, a fast Kalman prediction filter was applied to the input signal and the predicted tumor position was used for the application of tracking treatments.…”

Section: Treatment Deliverymentioning

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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“…Another approach to reducing the impact is to minimize the motion itself by incorporating compression belts27 to restrict diaphragm contraction and expansion, implementing breath hold techniques23, 28, 29, 30 or gating the treatment by restricting delivery to particular components of the breathing cycle 14, 20, 25, 31, 32. Recent works from several research groups have also investigated the tracking of tumor by dynamic correction of MLC positions 33, 34, 35, 36, 37. In the majority of these solutions the objective is to minimize the ITV volume, and thus the PTV volume.…”

Section: Introductionmentioning

confidence: 99%

Robust optimization of VMAT for lung cancer: Dosimetric implications of motion compensation techniques

Archibald-Heeren

Byrne

et al. 2017

J Applied Clin Med Phys

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In inverse planning of lung radiotherapy, techniques are required to ensure dose coverage of target disease in the presence of tumor motion as a result of respiration. A range of published techniques for mitigating motion effects were compared for dose stability across 5 breath cycles of ±2 cm. Techniques included planning target volume (PTV) expansions, internal target volumes with (OITV) and without tissue override (ITV), average dataset scans (ADS), and mini‐max robust optimization. Volumetric arc therapy plans were created on a thorax phantom and verified with chamber and film measurements. Dose stability was compared by DVH analysis in calculations across all geometries. The lung override technique resulted in a substantial lack of dose coverage (−10%) to the tumor in the presence of large motion. PTV, ITV and ADS techniques resulted in substantial (up to 25%) maximum dose increases where solid tissue travelled into low density optimized regions. The results highlight the need for care in optimization of highly heterogeneous where density variations may occur with motion. Robust optimization was shown to provide greater stability in both maximum (<3%) and minimum dose variations (<2%) over all other techniques.

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Electromagnetic guided couch and multileaf collimator tracking on a TrueBeam accelerator

Cited by 42 publications

References 21 publications

Validation of dynamic treatment-couch tracking for prostate SBRT

Validation of dynamic treatment-couch tracking for prostate SBRT

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

Robust optimization of VMAT for lung cancer: Dosimetric implications of motion compensation techniques

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