Robotic real-time translational and rotational head motion correction during frameless stereotactic radiosurgery

Liu, Xinmin; Belcher, AH; Grelewicz, Z; Wiersma, R

doi:10.1118/1.4919279

Cited by 8 publications

(9 citation statements)

References 19 publications

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“…The mechanical positioning accuracy of this system was less than that of other similar robotic applications, such as those presented by Liu 12 or Ostyn 11 . For example, our previously introduced system had a positioning error of 0.4 ± 0.3 mm error, compared to the 0.7 ± 0.3 mm of the system in this work.…”

Section: Resultsmentioning

confidence: 75%

“…One of the main challenges in the design of a fully radiotherapy-compatible robotic system is to make it as compact as possible, while still maintaining a meaningful range of control motions. Previous systems 12–14 that aim to adjust the head and neck positions have taken the form of an exertion of the couch top. The idea is to put all metal mechanical components placed below the patient’s head or as a separate accessory placed between the couch top and patient head.…”

Section: Resultsmentioning

confidence: 99%

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Radiotherapy-Compatible Robotic System for Multi-Landmark Positioning in Head and Neck Cancer Treatments

Ostyn

Wang

Kim

et al. 2019

Sci Rep

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The spine flexibility creates one of the most significant challenges to proper positioning in radiation therapy of head and neck cancers. Even though existing immobilization techniques can reduce the positioning uncertainty, residual errors (2–3 mm along the cervical spine) cannot be mitigated by single translation-based approaches. Here, we introduce a fully radiotherapy-compatible electro-mechanical robotic system, capable of positioning a patient’s head with submillimeter accuracy in clinically acceptable spatial constraints. Key mechanical components, designed by finite element analysis, are fabricated with 3D printing and a cyclic loading test of the printed materials captures a great mechanical robustness. Measured attenuation of most printed components is lower than analytic estimations and radiographic imaging shows no visible artifacts, implying full radio-compatibility. The new system evaluates the positioning accuracy with an anthropomorphic skeletal phantom and optical tracking system, which shows a minimal residual error (0.7 ± 0.3 mm). This device also offers an accurate assessment of the post correction error of aligning individual regions when the head and body are individually positioned. Collectively, the radiotherapy-compatible robotic system enables multi-landmark setup to align the head and body independently and accurately for radiation treatment, which will significantly reduce the need for large margins in the lower neck.

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Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Radiotherapy-Compatible Robotic System for Multi-Landmark Positioning in Head and Neck Cancer Treatments

Ostyn

Wang

Kim

et al. 2019

Sci Rep

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“…To maintain dynamic behavior of systems in the face of perturbations and other uncertainties, a robust control for parallel robotic platforms was investigated and compared with a widely used PID approach using extensive computer simulations [29]. For robotic SRS based head motion with angular stabilization, a decoupling control method for a 4D (xyz+pitch) robot was investigated [30, 31].…”

Section: Introductionmentioning

confidence: 99%

Optimization based trajectory planning for real-time 6DoF robotic patient motion compensation systems

Liu

Wiersma

2019

PLoS ONE

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PurposeRobotic stabilization of a therapeutic radiation beam with respect to a dynamically moving tumor target can be accomplished either by moving the radiation source, the patient, or both. As the treatment beam is on during this process, the primary goal is to minimize exposure of normal tissue to radiation as much as possible when moving the target back to the desired position. Due to the complex mechanical structure of 6 degree-of-freedom (6DoF) robots, it is not intuitive as to what 6 dimensional (6D) correction trajectory is optimal in achieving such a goal. With proportional-integrative-derivative (PID) and other controls, the potential exists that the controller may generate a trajectory that is highly curved, slow, or suboptimal in that it leads to unnecessary exposure of healthy tissue to radiation. This work investigates a novel feedback planning method that takes into account a robot’s mechanical joint structure, patient safety tolerances, and other system constraints, and performs real-time optimization to search the entire 6D trajectory space in each time cycle so it can respond with an optimal 6D correction trajectory.MethodsComputer simulations were created for two 6DoF robotic patient support systems: a Stewart-Gough platform for moving a patient’s head in frameless maskless stereotactic radiosurgery, and a linear accelerator treatment table for moving a patient in prostate cancer radiation therapy. Motion planning was formulated as an optimization problem and solved at real-time speeds using the L-BFGS algorithm. Three planning methods were investigated, moving the platform as fast as possible (platform-D), moving the target along a straight-line (target-S), and moving the target based on the fastest descent of position error (target-D). Both synthetic motion and prior recorded human motion were used as input data and output results were analyzed.ResultsFor randomly generated 6D step-like and sinusoidal synthetic input motion, target-D planning demonstrated the smallest net trajectory error in all cases. On average, optimal planning was found to have a 45% smaller target trajectory error than platform-D control, and a 44% smaller target trajectory error than target-S planning. For patient head motion compensation, only target-D planning was able to maintain a ≤0.5mm and ≤0.5deg clinical tolerance objective for 100% of the treatment time. For prostate motion, both target-S planning and target-D planning outperformed platform-D control.ConclusionsA general 6D target trajectory optimization framework for robotic patient motion compensation systems was investigated. The method was found to be flexible as it allows control over various performance requirements such as mechanical limits, velocities, acceleration, or other system control objectives.

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“…A wide variety of methods have been proposed for directly addressing such intrafractional motion. Among the most advanced, is the use of real-time patient motion compensation, where prior works include the use of a robotic arm to move a compact LINAC in sync with a tumor (Adler Jr, Chang, Murphy, Doty, Geis & Hancock 1997) Liu, Belcher, Grelewicz & Wiersma 2015, Belcher, Liu, Grelewicz, Kamil & Wiersma 2017. However, these methods typically employ a static treatment plan, and do not dynamically adapt this plan to real-time changes in patient anatomy.…”

Section: Introductionmentioning

confidence: 99%

A conceptual study on real-time adaptive radiation therapy optimization through ultra-fast beamlet control

Wiersma

Liu

2019

Biomed. Phys. Eng. Express

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A central problem in the field of radiation therapy (RT) is how to optimally deliver dose to a patient in a way that fully accounts for anatomical position changes over time. As current RT is a static process, where beam intensities are calculated before the start of treatment, anatomical deviations can result in poor dose conformity. To overcome these limitations, we present a simulation study on a fully dynamic real-time adaptive radiation therapy (RT-ART) optimization approach that uses ultra-fast beamlet control to dynamically adapt to patient motion in real-time. A virtual RT-ART machine was simulated with a rapidly rotating linear accelerator (LINAC) source (60 RPM) and a binary 1D multi-leaf collimator (MLC) operating at 100 Hz. If the real-time tracked target motion exceeded a predefined threshold, a time dependent objective function was solved using fast optimization methods to calculate arXiv:1811.03665v3 [physics.med-ph] 1 Sep 2019

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Robotic real-time translational and rotational head motion correction during frameless stereotactic radiosurgery

Cited by 8 publications

References 19 publications

Radiotherapy-Compatible Robotic System for Multi-Landmark Positioning in Head and Neck Cancer Treatments

Radiotherapy-Compatible Robotic System for Multi-Landmark Positioning in Head and Neck Cancer Treatments

Optimization based trajectory planning for real-time 6DoF robotic patient motion compensation systems

A conceptual study on real-time adaptive radiation therapy optimization through ultra-fast beamlet control

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