Magnetic Resonance Image Guided Radiation Therapy for External Beam Accelerated Partial-Breast Irradiation: Evaluation of Delivered Dose and Intrafractional Cavity Motion

Acharya, Sahaja; Fischer‐Valuck, Benjamin W.; Mazur, Thomas R.; Curcuru, Austen; Sona, Karl; Kashani, Rojano; Green, Olga; Ochoa, Laura; Mutic, Sasa; Zoberi, Imran; Li, H. Harold; Thomas, Maria

doi:10.1016/j.ijrobp.2016.08.006

Cited by 77 publications

(98 citation statements)

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“…Additionally, the PTV margins chosen for this study were conservative, at 0.5 cm from the GTV, an expansion that was selected to match that of typical CT-guided SBRT, in order to avoid excessive departures from standard-ofcare SBRT practice in this first application of SMART. However, given the soft tissue visualization improvements of MR-IGRT, reduced PTV margin size has now been applied in select MR-guided scenarios and is of ongoing interest in future studies [35].…”

Section: Discussionmentioning

confidence: 99%

Phase I trial of stereotactic MR-guided online adaptive radiation therapy (SMART) for the treatment of oligometastatic or unresectable primary malignancies of the abdomen

Henke

Kashani

Robinson

et al. 2018

Radiotherapy and Oncology

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Section: Discussionmentioning

confidence: 99%

Phase I trial of stereotactic MR-guided online adaptive radiation therapy (SMART) for the treatment of oligometastatic or unresectable primary malignancies of the abdomen

Henke

Kashani

Robinson

et al. 2018

Radiotherapy and Oncology

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355

353

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“…According to their results, the mean difference between planned and delivered dose was within 1 %. [26] Similarly, another group used MRI with two time scales (2D and 3D MRI) showing a median deviation of about 2 vs. 2.2 mm. [27] MR-imaging during RT represents an elegant and promising approach to track target volumes in real time, especially in soft tissues including breast.…”

Section: Discussionmentioning

confidence: 99%

Real-time intra-fraction motion management in breast cancer radiotherapy: analysis of 2028 treatment sessions

et al. 2018

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BackgroundIntra-fraction motion represents a crucial issue in the era of precise radiotherapy in several settings, including breast irradiation. To date, only few data exist on real-time measured intra-fraction motion in breast cancer patients. Continuous surface imaging using visible light offers the capability to monitor patient movements in three-dimensional space without any additional radiation exposure. The aim of the present study was to quantify the uncertainties of possible intra-fractional motion during breast radiotherapy.Material and methodsOne hundred and four consecutive patients that underwent postoperative radiotherapy following breast conserving surgery or mastectomy were prospectively evaluated during 2028 treatment sessions. During each treatment session the patients’ motion was continuously measured using the Catalyst™ optical surface scanner (C-RAD AB, Sweden) and compared to a reference scan acquired at the beginning of each session. The Catalyst system works through an optical surface imaging with light emitting diode (LED) light and reprojection captured by a charge coupled device (CCD) camera, which provide target position control during treatment delivery with a motion detection accuracy of 0.5 mm. For 3D surface reconstruction, the system uses a non-rigid body algorithm to calculate the distance between the surface and the isocentre and using the principle of optical triangulation. Three-dimensional deviations and relative position differences during the whole treatment fraction were calculated by the system and analyzed statistically.ResultsOverall, the maximum magnitude of the deviation vector showed a mean change of 1.93 mm ± 1.14 mm (standard deviation [SD]) (95%-confidence interval: [0.48–4.65] mm) and a median change of 1.63 mm during dose application (beam-on time only). Along the lateral and longitudinal axis changes were quite similar (0.18 mm ± 1.06 mm vs. 0.17 mm ± 1.32 mm), on the vertical axis the mean change was 0.68 mm ± 1.53 mm. The mean treatment session time was 154 ± 53 (SD) seconds and the mean beam-on time only was 55 ± 16 s. According to Friedman’s test differences in the distributions of the three possible directions (lateral, longitudinal and vertical) were significant (p < 0.01), in post-hoc analysis there were no similarities between any two of the three directions.ConclusionThe optical surface imaging system is an accurate and easy tool for real-time motion management in breast cancer radiotherapy. Intra-fraction motion was reported within five millimeters in all directions. Thus, intra-fraction motion in our series of 2028 treatment sessions seems to be of minor clinical relevance in postoperative radiotherapy of breast cancer.

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“…Moreover, pre- and post-treatment acquisitions cannot capture intra-fractional breast motion. Real-time magnetic resonance image (MRI) has also been reported to track breast motion [ 21 , 22 ], though MRI can provide superior soft-tissue contrast of the tumor bed, the reported studies are merely focused on intra-fractional motion using 2D MRI images with limited resolution (e.g. 3.5 mm × 3.5 mm in [ 21 ]).…”

Section: Discussionmentioning

confidence: 99%

“…Real-time magnetic resonance image (MRI) has also been reported to track breast motion [ 21 , 22 ], though MRI can provide superior soft-tissue contrast of the tumor bed, the reported studies are merely focused on intra-fractional motion using 2D MRI images with limited resolution (e.g. 3.5 mm × 3.5 mm in [ 21 ]). In contrast, the near real-time fiducial positions logged by the Cyberknife kV imaging system offer complete data set on breast target geometric changes during the course of treatment, allowing a comprehensive study of breast target geometric errors.…”

Section: Discussionmentioning

confidence: 99%

Comprehensive target geometric errors and margin assessment in stereotactic partial breast irradiation

et al. 2017

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BackgroundRecently developed stereotactic partial breast irradiation (S-PBI) allows delivery of a high biologically potent dose to the target while sparing adjacent critical organs and normal tissue. With S-PBI tumoricidal doses, accurate and precise dose delivery is critical to achieve high treatment quality. This study is to investigate both rigid and non-rigid components of target geometric error and their corresponding margins in S-PBI and identify correlated clinical factors.MethodsForty-three early-stage breast cancer patients with implanted gold fiducial markers were enrolled in the study. Fiducial positions recorded on the orthogonal kV images on a Cyberknife system during treatment were used to estimate intra-fraction errors and composite errors (including intra-fraction errors and residual errors after patient setup). Both rigid and non-rigid components of intra-fraction and composite errors were analyzed and used to estimate rigid and non-rigid margins, respectively. Univariate and multivariate linear regressions were conducted to evaluate correlations between clinical factors and errors.ResultsFor the study group, the intra-fraction rigid and non-rigid errors are 2.0 ± 0.6 mm and 0.3 ± 0.2 mm, respectively. The composite rigid and non-rigid errors are 2.3 ± 0.5 mm and 1.3 ± 0.8 mm, respectively. The rigid margins in the left-right, anterior-posterior, and superior-inferior directions are estimated as 2.1, 2.4, and 2.3 mm, respectively. The estimated non-rigid margin, assumed to be isotropic, is 1.7 mm. The outer breast quadrants are more susceptible to composite errors occurrence than the inner breast quadrants. The target to chest wall distance is the clinical factor correlated with target geometric errors.ConclusionsThis is the first comprehensive analysis of breast target geometric rigid and non-rigid errors in S-PBI. Upon the estimation, the non-rigid margin is comparable to rigid margin, and therefore should be included in planning target volume as it cannot be accounted for by the Cyberknife system. Treatment margins selection also need to consider the impact of relevant clinical factor.Electronic supplementary materialThe online version of this article (10.1186/s13014-017-0889-6) contains supplementary material, which is available to authorized users.

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Magnetic Resonance Image Guided Radiation Therapy for External Beam Accelerated Partial-Breast Irradiation: Evaluation of Delivered Dose and Intrafractional Cavity Motion

Cited by 77 publications

References 25 publications

Phase I trial of stereotactic MR-guided online adaptive radiation therapy (SMART) for the treatment of oligometastatic or unresectable primary malignancies of the abdomen

Phase I trial of stereotactic MR-guided online adaptive radiation therapy (SMART) for the treatment of oligometastatic or unresectable primary malignancies of the abdomen

Real-time intra-fraction motion management in breast cancer radiotherapy: analysis of 2028 treatment sessions

Comprehensive target geometric errors and margin assessment in stereotactic partial breast irradiation

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