The impact of respiratory gating on lung dosimetry in stereotactic body radiotherapy for lung cancer

Jang, Seong Soon; Huh, Gil Ja; Park, Suk Young; Yang, Po Song; Cho, Eun Youn

doi:10.1016/j.ejmp.2014.05.005

Cited by 34 publications

(30 citation statements)

References 28 publications

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“…Despite a longer delivery time, the dosimetric benefits of RG have been well established in the treatment of tumors that are affected by respiratory motion [17,18]. The reduced margins allowed by RG make it possible to safely escalate tumor doses without increasing the risk of normal tissue complications or to better protect normal tissues at conventional doses [19,20].…”

Section: Discussionmentioning

confidence: 99%

Are fiducial markers useful surrogates when using respiratory gating to reduce motion of gastroesophageal junction tumors?

Liu

Huguet

et al. 2016

Acta Oncologica

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Background Radiation therapy (RT) is an integral component of the management of gastroesophageal junction (GEJ) tumors. We evaluated the use of implanted radiopaque fiducials as tumor surrogates to allow for more focal delivery of RT to these mobile tumors when using respiratory gating (RG) to reduce motion. Material and methods We analyzed four-dimensional computed tomography scans of 20 GEJ patients treated with RG and assessed correlation between tumor and implanted fiducial motion over the whole respiratory cycle and within a clinically realistic gate around end-exhalation. We evaluated fiducial motion concordance in 11 patients with multiple fiducials. Results Gating reduced anterior-posterior (AP) and superior-inferior (SI) mean tumor and fiducial motions by over 50%. Fiducials and primary tumor motions were moderately correlated: R2 for AP and SI linear fits to the entire group were 0.54 and 0.68, respectively, but the correlation had strong interpatient variation. For all patients with multiple fiducials, relative in-gate displacements were below 3 mm; results were similar for eight of 11 patients over the whole cycle. Conclusion Implanted fiducial and gross tumor volume (GTV) motions correlate well but the correlation is patient-specific and may be dependent on the location of the fiducials with respect to the GTV.

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Section: Discussionmentioning

confidence: 99%

Are fiducial markers useful surrogates when using respiratory gating to reduce motion of gastroesophageal junction tumors?

Liu

Huguet

et al. 2016

Acta Oncologica

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“…The AAPM Task Group 765 presented the following summation on review of the literature; “The amount a lung tumor moves during breathing varies widely…There are no general patterns of respiratory behavior that can be assumed for a particular patient prior to observation and treatment”. Many of the reviewed studies6, 7, 8, 9, 10, 11, 12, 13 had focused on quantifying the magnitude of such tumor motion, showing variations as great as 34 mm, 22 mm, and 12 mm in the cranio‐caudal, anterior‐posterior, and lateral directions respectively, in some patients 14. Traditional planning methods provide suitable coverage of mobile Gross Tumour Volumes (GTV) by creation of Internal Target Volumes (ITV) which encompasses the GTV through its respiratory motion.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

“…In the majority of these solutions the objective is to minimize the ITV volume, and thus the PTV volume. Whilst some of the systems, as individual or combined solutions, are showing promising results in reduction in irradiated volumes and healthy tissue doses,14, 23, 28, 38 they provide a solution to only one half of the motion induced problem.…”

Section: Introductionmentioning

confidence: 99%

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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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“…Real-time four-dimensional radiotherapy, which includes beam gating [5][6][7] and beam tracking [8,9], has been realized in photon therapy to mitigate the dosimetric impacts of target motion. Gating [10][11][12] and tracking techniques [13,14] using external surrogates have also been reported in particle therapy.…”

Section: Introductionmentioning

confidence: 99%

Optimization and evaluation of multiple gating beam delivery in a synchrotron-based proton beam scanning system using a real-time imaging technique

et al. 2016

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(Naoki Miyamoto) Purpose:To find the optimum parameter of a new beam control function installed in a synchrotron-based proton therapy system. Methods:A function enabling multiple gated irradiation in the flat top phase has been installed in a real-time-image gated proton beam therapy (RGPT) system. This function is realized by a waiting timer that monitors the elapsed time from the last gate-off signal in the flat top phase. The gated irradiation efficiency depends on the timer value, T w . To find the optimum T w value, gated irradiation efficiency was evaluated for each configurable T w value. 271 gate signal data sets from 58 patients were used for the simulation. Results:The highest mean efficiency 0.52 was obtained in T W = 0.2 s. The irradiation efficiency was approximately 21% higher than at T W = 0 s, which corresponds to ordinary synchrotron operation. The irradiation efficiency was improved in 154 (57%) of the 271 cases. The irradiation efficiency was reduced in 117 cases because the T W value was insufficient or the function introduced an unutilized wait time for the next gate-on signal in the flat top phase. In the actual treatment of a patient with a hepatic tumor at T w = 0.2 s, 4.48 GyE irradiation was completed within 250 s. In contrast, the treatment time of ordinary synchrotron operation was estimated to be 420 s. Conclusions:The results suggest that the multiple gated-irradiation function has potential to improve the gated irradiation efficiency and to reduce the treatment time.

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The impact of respiratory gating on lung dosimetry in stereotactic body radiotherapy for lung cancer

Cited by 34 publications

References 28 publications

Are fiducial markers useful surrogates when using respiratory gating to reduce motion of gastroesophageal junction tumors?

Are fiducial markers useful surrogates when using respiratory gating to reduce motion of gastroesophageal junction tumors?

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

Optimization and evaluation of multiple gating beam delivery in a synchrotron-based proton beam scanning system using a real-time imaging technique

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