Motion management during IMAT treatment of mobile lung tumors—A comparison of MLC tracking and gated delivery

Falk, Marianne; Pommer, Tobias; Keall, Paul J.; Korreman, S.; Persson, Gitte Fredberg; Poulsen, Per Rugaard; Rosenschöld, Per Munck af

doi:10.1118/1.4896024

Cited by 20 publications

(22 citation statements)

References 45 publications

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“…Dynamic multi-leaf collimator (MLC) tracking for a standard gantry-based linac has recently been used clinically for the first time, 40 although not for lung cancer but prostate cancer treatment. MLC tracking for lung cancer is still in development.…”

Section: Motion Trackingmentioning

confidence: 99%

Image-guided radiotherapy and motion management in lung cancer

Korreman¹

2015

BJR

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In this review, image guidance and motion management in radiotherapy for lung cancer is discussed. Motion characteristics of lung tumours and image guidance techniques to obtain motion information are elaborated. Possibilities for management of image guidance and motion in the various steps of the treatment chain are explained, including imaging techniques and beam delivery techniques. Clinical studies using different motion management techniques are reviewed, and finally future directions for image guidance and motion management are outlined.

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Section: Motion Trackingmentioning

confidence: 99%

Image-guided radiotherapy and motion management in lung cancer

Korreman¹

2015

BJR

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“…So far, performance studies on motion management have employed geometrical, rigid motion phantoms whose main advantage is motion reproducibility, neglecting human anatomy. Falk et al [17] used a Delta 4 phantom (ScandiDos, Sweden) mounted on a motion platform to measure delivery performance of gating and tracking strategies. Menten et al [18] simply used films within solid water, mounted on a motion platform, to compare accuracy of different tracking strategies.…”

Section: Discussionmentioning

confidence: 99%

“…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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“…Falk and colleagues28 recently reported on the delivery efficiency of motion‐tracking plan. They pointed out an increased treatment time could potentially increase the risk of systematic drifts of the tumor position.…”

Section: Discussionmentioning

confidence: 99%

“…Tumor motion tracking is a recent development toward improving dose delivery quality. Compared with the common techniques of motion management such as respiratory gating and forced shallow breathing, motion‐tracking technique provides shorter treatment delivery time and requires less patient co‐operation and causes less patient discomfort 27, 28, 29…”

Section: Introductionmentioning

confidence: 99%

Effects of collimator angle, couch angle, and starting phase on motion‐tracking dynamic conformal arc therapy (4D DCAT)

Yao

Podgorsak

et al. 2017

J Applied Clin Med Phys

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PurposeThe aim of this study was to find an optimized configuration of collimator angle, couch angle, and starting tracking phase to improve the delivery performance in terms of MLC position errors, maximal MLC leaf speed, and total beam‐on time of DCAT plans with motion tracking (4D DCAT).Method and materialsNontracking conformal arc plans were first created based on a single phase (maximal exhalation phase) of a respiratory motion phantom with a spherical target. An ideal model was used to simulate the target motion in superior‐inferior (SI), anterior‐posterior (AP), and left‐right (LR) dimensions. The motion was decomposed to the MLC leaf position coordinates for motion compensation and generating 4D DCAT plans. The plans were studied with collimator angle ranged from 0° to 90°; couch angle ranged from 350°(−10°) to 10°; and starting tracking phases at maximal inhalation (θ=π/2) and exhalation (θ=0) phases. Plan performance score (PPS) evaluates the plan complexity including the variability in MLC leaf positions, degree of irregularity in field shape and area. PPS ranges from 0 to 1, where low PPS indicates a plan with high complexity. The 4D DCAT plans with the maximal and the minimal PPS were selected and delivered on a Varian TrueBeam linear accelerator. Gafchromic‐EBT3 dosimetry films were used to measure the dose delivered to the target in the phantom. Gamma analysis for film measurements with 90% passing rate threshold using 3%/3 mm criteria and trajectory log files were analyzed for plan delivery accuracy evaluation.ResultsThe maximal PPS of all the plans was 0.554, achieved with collimator angle at 87°, couch angle at 350°, and starting phase at maximal inhalation (θ=π/2). The maximal MLC leaf speed, MLC leaf errors, total leaf travel distance, and beam‐on time were 20 mm/s, 0.39 ± 0.16 mm, 1385 cm, and 157 s, respectively. The starting phase, whether at maximal inhalation or exhalation had a relatively small contribution to PPS (0.01 ± 0.05).ConclusionsBy selecting collimator angle, couch angle, and starting tracking phase, 4D DCAT plans with the maximal PPS demonstrated less MLC leaf position errors, lower maximal MLC leaf speed, and shorter beam‐on time which improved the performance of 4D motion‐tracking DCAT delivery.

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Motion management during IMAT treatment of mobile lung tumors—A comparison of MLC tracking and gated delivery

Cited by 20 publications

References 45 publications

Image-guided radiotherapy and motion management in lung cancer

Image-guided radiotherapy and motion management in lung cancer

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

Effects of collimator angle, couch angle, and starting phase on motion‐tracking dynamic conformal arc therapy (4D DCAT)

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