Lung SBRT with the CyberKnife® System

Real-time respiration tracking for unmatched precision

The revolutionary Synchrony® Respiratory Tracking System powers radically precise, highly effective non-surgical treatments for lung cancer regardless of the tumor complexity and location.

CyberKnife central lung

Precise robotic treatment as individual as every patient

The CyberKnife System combines advanced robotic treatment and sophisticated respiratory motion tracking technology to dynamically align the treatment beam to the moving tumor, enabling the clinical team to deliver high doses of radiation with extreme precision and providing the patient with personalized treatment.

Accuray CyberKnife Dynamic SBRT Lung Tracking
Accuray CyberKnife Dynamic SBRT Lung Tracking
CyberKnife Prostate Outcomes

Demonstrated Clinical Benefits

For prostate cancer, unpredictable motion and rotation are tracked and automatically corrected with the 6 axis robotic arm resulting in excellent clinical outcome as demonstrated by two recent SBRT clinical studies4,5. These prospective, multi-institutional and device-specific (CyberKnife® System only) clinical studies—the largest of their kind to date—provide robust clinical data supporting the safety and efficacy of CyberKnife Stereotactic Body Radiotherapy (SBRT) for patients with low- and intermediate-risk prostate cancer.

Prospective evaluation of CyberKnife System stereotactic radiosurgery for low and intermediate risk prostate cancer:

Homogenous Dose Distribution

Prospective evaluation of CyberKnife System stereotactic radiosurgery for low and intermediate risk prostate cancer:

Emulating HDR brachytherapy dosimetry

Real-time Motion Correction

The CyberKnife fully integrated image-guidance system continually acquires stereoscopic kV images during treatment, tracks motion and automatically corrects the treatment beam alignment in real-time1. The 6-axis robotic arm aims each treatment beam taking into account tumor motion throughout treatment delivery. All measured displacements are automatically corrected, regardless of how small, maintaining sub-millimeter accuracy1-7.

Predictive Respiration Tracking and Correction

For tumors that move with respiration, the Synchrony Respiratory Tracking System tracks the breathing motion with an optical camera, allowing the patient to breathe normally while the beam moves in synchrony with the tumor. The innovative Synchrony system builds a correlation model—continually updated during treatment to account for changes in the breathing pattern—that predicts the tumor motion ahead by 120 milliseconds to account for the robotic correction latency. This technology eliminates the need for internal target volume (ITV), keeps a safe clinical target volume (CTV) for microscopic extension, and allows a small planning target volume (PTV).

Frameless stereotactic targeting

The CyberKnife System enables stereotactic targeting without a stereotactic frame, enhancing patient comfort and simplifying the procedure. Simple immobilization devices such as thermoplastic masks, a foam cradle or vacuum bags keep the patient comfortably in treatment position and prevent large displacements that cannot be compensated by the robotic arm.

Illustration of frameless stereotactic targeting for lung cancer with the CyberKnife System from Accuray
CyberKnife chest wall

Sharp dose gradient

The robotic design of the CyberKnife System seamlessly delivers non-coplanar, non-isocentric and isocentric beams. This wide range of available beam angles sculpts conformal dose distributions and enables safe and effective treatments regardless of the target complexity and location. It generates the sharp dose gradient required for lesions close to critical structures and minimizes dose delivered to normal tissues.

Validated accuracy

The CyberKnife system uses proprietary anatomy-specific algorithms to track tumor motion. These specialized image guidance algorithms enable sub-millimeter precision and accuracy without the need for invasive and cumbersome stereotactic frame 1-7. Academic institutions have independently validated the image guidance sub-millimeter accuracy.

CyberKnife Lung

6D Skull Tracking, total system error:

  • 0.95 mm (Accuray Specification)
  • 0.48 ± 0.22 mm2
  • 0.30 ± 0.12 mm6
  • 0.44 ± 0.12 mm3

Fiducial Tracking, total system error:

  • 0.95 mm (Accuray Specification)
  • 0.29 ± 0.10 mm3

Xsight® Spine Tracking, total system error:

  • 0.95 mm (Accuray Specification)
  • 0.53 ± 0.16 mm3
  • 0.52 ± 0.22 mm4
  • 0.61 ± 0.27 mm5

Synchrony® Respiratory Tracking System, total system error:

  • 0.95 mm (Accuray specification)
  • < 0.6 mm7

Versatility in collimator options

The CyberKnife system offers a collection of available collimators, providing the versatility needed to treat a wide range of clinical indications from trigeminal neuralgia to large tumors.

  • Fixed Circular Collimators
  • Iris Variable Aperture Collimator
  • InCise 2 Multileaf Collimator

Demonstrated clinical benefits

The CyberKnife System enables safe and effective SBRT for central lung tumors surrounded by sensitive structures7 and lung tumors near the chest wall8. It also provides excellent clinical outcomes for patients with inoperable peripheral lung tumors9-11. Furthermore, a pooled analysis of two randomized trials indicates that lung SBRT is better tolerated and might lead to better overall survival compared to surgery for operable early-state lung cancer12.

CyberKnife central lung

Clinical Examples



CyberKnife System Accuracy:

1) Kilby W. et al. “The CyberKnife® Robotic Radiosurgery System in 2010” TCRT. 2010; 9(5): 433-452 –

2) Muacevic A. et al. “Feasibility, safety, and outcome of frameless image-guided robotic radiosurgery for brain metastases.” J Neurooncol. 2010; 97: 267-274

3) Antypas C. and Pantelis E. “Performance evaluation of a CyberKnife G4
image-guided robotic stereotactic radiosurgery system.” Phys Med Biol.
53:4697-4718, 2008

4) Muacevic A. et. al. “Technical description, phantom accuracy, and clinical feasibility for fiducial-free frameless real-time image-guided spinal radiosurgery” J Neurosurgery Spine. 2006; 5(4): 303-312 –

5) Ho et. al. “A study of the accuracy of cyberknife spinal radiosurgery using skeletal structure tracking” Neurosurgery. 2007; 60: 147-156

6) Romanelli P. et al. “Image-Guided Robotic Radiosurgery for Trigeminal Neuralgia” Neurosurgery. 2017; Nyx571 –

7) Muacevic A. et. al. “Technical Description, Phantom Accuracy, and Clinical Feasibility for Single-session Lung Radiosurgery Using Robotic Image-guided Real-time Respiratory Tumor Tracking” TCRT. 2007; 6(4): 321-328 –



7) Nuyttens J.J. et al. “Outcome of four-dimensional stereotactic radiotherapy for centrally located long tumors” Radiotherapy and Oncology. 2012; 102: 383-387

8) Podder T. et al. “Chest wall and rib irradiation and toxicities of early-stage lung cancer patients treated with CyberKnife stereotactic body radiotherapy.” Future oncology. 2014; 10(15): 2311-2317

9) Brown W.T. et al. “Application of robotic stereotactic radiotherapy to peripheral state I non-small cell lung cancer with curative intent.” Clin Oncol (R Coll Radiol). 2009; 21: 623-631

10) Snider J.W. et al. “CyberKnife with tumor tracking: an effective treatment for high-risk surgical patients with single peripheral lung metastases” Front Oncol. 2012; 2: 63 –

11) Lischalk J.W. et al. “Long-term outcomes of stereotactic body radiation therapy (sbrt) with fiducial tracking for inoperable stage I non-small cell lung cancer (nsclc).” J Radiat Oncol. 2016; 5: 379-387 –

12) Chang S. et al. “Stereotactic ablative radiotherapy versus lobectomy for opereable stage I non-small-cell lung cancer: a pooled analysis of two rancomised trials.” Lancet Oncol. 2015; 16(6) 630-637 –



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