Early Experience with InCise2 Equipped Cyberknife

CHARLES SHANG, BMed, MS, FAAPM Affiliate Research Professor, Physics & Engineering, FAU

Director of Medical Physics, Lynn Cancer Institute, Boca Raton Regional Hospital

Introduction of CyberKnife M6 with InCise2 MLC SRS Treatment using Cyberknife Tumor Tracking with Cyberknife CyberKnife QA

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Presenter has NO financial interest in any of the technology reported here.

InCiseTM2 MLC – M6 MLC Mount

M6 Robot, 6 MV Photon Fixed Target FFF (Flattening Filter Free) 1000 MU/min Dose Rate

Courtesy of Accuray

InCiseTM2 MLC – MLC Shapes

2 banks of 26 leaves– 3.85 mm thickness

Max 115x100 mm at 80SAD Focusing:

Crossline- beveled Inline- towards focus

Leaf positioning accuracy ≤ 0.95 mm at SAD Transmission through

leaves: Max <0.5%, Ave =0.3% at dmax Leaf-tip leakage (closed leaves at full over-

travel) Max < 0.5% at dmax

Courtesy of Accuray

InCiseTM2 MLC – Leaf 2nd Feedback Distal plane of leaves

to source: 400 mm 100% over-travel,

Full-interdigitation

Secondary feedback system detects differences in leaf actual position from primary and triggers interlock if > 1 mm

Courtesy of Accuray

InCiseTM2 MLC – Stereo Imagers

Filter 2.5 mm Al Expose simultaneously Burst 8-pairs to build the

synchrony model Burst 3-pairs to confirm synchrony

Courtesy of Accuray

InCiseTM2 MLC –Small Field Issue

Pantelis et al.: Experimental determination of correction factors for OF measurements, Medical Physics, Vol. 39, No. 8, August 2012

0.936

Selection of Microchambers Apply correction factors

InCiseTM2 MLC –Small Field Issue

Moignier, Huet, and Makovicka: Detector response to small photon beams, Medical Physics, Vol. 41, No. 7, August 2014

Monte Carlo simulated primary beam: Its parameters include: energy (E) and full width at half maximum (FWHM) of the Gaussian radial distribution.

InCiseTM2 MLC –Beam Specification

Node: Location of beam source Node => Multi-beams => Multi-segments Path Set: Set of nodes associated with

Head, Body, QA Conformal Targeting

Target points randomly distributed over surface of tumor

Courtesy of Accuray

Introduction of CyberKnife M6 with InCise2 MLC SRS Treatment using Cyberknife Tumor Tracking with Cyberknife CyberKnife QA

TOPICS

Conclusions Cranial SRS by Cyberknife

First CyberKnife Case: Dec 16, 2015.

Conclusions Cranial SRS by Cyberknife

Cranial SRS by Cyberknife

Shang C: Medical Physics in Quality Radiological Imaging/ISEP Workshop in Kaunas, Lithuania. May 2015

Cranial SRS by Cyberknife

fMRI with finger motion fMRI with hands motion

Shang C: Medical Physics in Quality Radiological Imaging/ISEP Workshop in Kaunas, Lithuania. May 2015

Cranial SRS by Cyberknife

Distortion of < 1mm is observed in the MR image along the z-axis with compared with CT images

Caution: Z-axis Geometric Distortion 3D MPRAGE with 12 channel head coils. Sagittal view, 5 mm intervals

Vergara1 D, Shang C, et al: Med. Phys. 39, 3694 (2012)

Pancreas SBRT by Cyberknife

Prostate SBRT by Cyberknife

Prostate SBRT by Cyberknife

Kathriarachchi V, Shang C (presenting), et al: Oral presentation, IUPESM World Congress on Medical Physics & Biomedical Engineering, Toronto, CA; June 2015. - Medical Physics, in press

Prostate SBRT by Cyberknife

Kathriarachchi V, Shang C (presenting), et al: Oral presentation, IUPESM World Congress on Medical Physics & Biomedical Engineering, Toronto, CA; June 2015

Introduction of CyberKnife M6 with InCise2 MLC SRS Treatment using Cyberknife Tumor Tracking with Cyberknife CyberKnife QA

TOPICS

Alignment accuracy. Large PTV margins. Organs at risk sparing Tumors in the thorax can move up to 3 to 5 cm, often 1.5 to 2.5 cm with respiration*.

Buyyounouski MK, Balter P, Lewis B, et al; Int J Rad Onc Bio Phy 2010;78:3-10

Challenges of Tumor Motion

Challenges:

Shang C: ASRT Radiation Therapy Conference, Boston, MA (Nov, 2012)

Motion of Lung Tumor

Tumor motion may appears more traceable according to a normal respiration pattern in younger patients.

Challenges of Tumor Motion

Shang C: ASRT Radiation Therapy Conference, Boston, MA (Nov, 2012)

Caveat of RPM Gating

Challenges of Gating

Shang C: International Workshop on Modern Clinical Radiotherapy, Jakarta, Indonesia (2014)

Uncertainty in surface surrogate based respiration gating: Tumor in certain regions of the lun may move disproportionally relative to its external surroga (ribs).

Caveat of RPM Gating 4 repeated helical 4D-CT were acquired every 10 min for 10 patients with 14 pulmonary metastases. Residual tumor position at given respiration bin varies when using an external respiration signal (RPM) .

Challenges of Gating

Guckenberger M, Wilbert J, Meyer J, et al.; Int J Rad Onc Bio Phy 2007;67:1352-1359

Uncertainty in surface surrogate based respiration gating: Tumor in certain regions of the lung may move disproportionally relative to its external surrogate (ribs).

Adaptive Treatment

•Courtesy of Accuray

Tumor Tracking by Cyberknife

Courtesy of Accuray

Xsight Lung Respiratory Track

ITV for 1-View-A

Courtesy of Accuray

Xsight Lung Respiratory Track

ITV for 1-View-A

Courtesy of Accuray

Motion of Respiration Xsight Lung Respiratory Track

With one-veiw of Xsight Lung Synchrony: Sup-Inf & perpendicular motions can be tracked

Lamb JM (UCLA), C. Robinson, J. Bradley, et al; Med Phy 2011; 38:5732-5737

Images for Moving Structures

Shang C: International Workshop on Modern Clinical Radiotherapy, Jakarta, Indonesia (2014)

Xsight Lung Respiratory Track

Cyberkife –Prediction Data: 100 treatment models of 23 de-identified lung patients

Xsight Lung Respiratory Track

Pepin E, et al: Med. Phys. 38, 4036 (2011)

The margin expansions needed for 95% coverage: LAT 1.2 mm, AP 1.7 mm, SI 3.5 mm. For 99% modeler point coverage: LAT 2.9 mm, AP 3.6 mm, SI “highly variable”

Margins 3.5

1.7

1.2

Margins 7?

3.6

2.9

Adaptive Treatment

•Courtesy of Accuray

Tumor Tracking by Cyberknife

Courtesy of Accuray

Conclusions Fiducial Respiratory Tracking

Conclusions Fiducial Respiratory Tracking

Conclusions Fiducial Respiratory Tracking

Conclusions Xsight Lung Respiratory Track

Introduction of CyberKnife M6 with InCise2 MLC SRS Treatment using Cyberknife Tumor Tracking with Cyberknife CyberKnife QA

TOPICS

Conclusions Cyberknife QA - Daily

Khanal S, Shang C, Giiard G, et al: Oral presentation, FLAAPM meeting; April 2016

Conclusions Cyberknife QA

Daily QA • Safety Interlock Checks – Laser at perch Check • X-ray Tube Warm-up • LINAC Output Constancy Check : Chamber or

SRSP • Automated Quality Assurance (AQA) Targeting

Reproducibility Test • MLC Reproducibility Test (Pick fence)

Dieterich S, et al: Report of AAPM TG 135, Med. Phys. 38 (6), June 2011 Accuray Inc. CyberKnife Manual

Conclusions Cyberknife QA - Daily

Khanal S, Shang C, Giiard G, et al: Oral presentation, FLAAPM meeting; April 2016

Conclusions Cyberknife QA

Monthly QA • Beam: Calibration,

Energy, Symmetry

• LINAC Laser and Radiation Coincidence

• End-to-End (E2E) Test

• Dose Delivery Verification: (patient specific test)

• Imaging System Alignment: (AQA, E2E)

• Standard Treatment Couch Positioning: (daily)

• MLC Reproducibility Test (Garden fence)

Dieterich S, et al: Report of AAPM TG 135, Med. Phys. 38 (6), June 2011 Accuray Inc. CyberKnife Manual

Conclusions Cyberknife QA

Quarterly QA • Tracking system & Couch movement:

Lung Synchrony E2E

• Iris collimator QA

Annual QA • Verification of beam energy, flatness,

symmetry and penumbra: 3D scans

• Imaging system QA and doses

• Spot checks of MultiPlan® data

• CT scanner geometric accuracy tests on all CT scanners

• Evaluate daily, monthly and quarterly trend for compliance with system performance specifications

Dieterich S, et al: Report of AAPM TG 135, Med. Phys. 38 (6), June 2011 Accuray Inc. CyberKnife Manual

Conclusions Patient Specific QA

Conclusions Patient Specific QA

Shang C: Invited presentation, FLAAPM meeting; April 2016

Conclusions Patient Specific QA

Shang C: Invited presentation, FLAAPM meeting; April 2016

Conclusions Patient Specific QA

Shang C: Invited presentation, FLAAPM meeting; April 2016

Conclusions Patient Specific QA

First CyberKnife Case: 3 Intracranial lesions Plan with 149 MLC seg Tx time 45 min Mapcheck QA

Patient Specific QA

3 Intracranial lesions

QA & Support

Accuray prompt customer support .

Conclusions We have successfully commissioned a new CyberKnife

with InCise-2 MLC.

CK has added tumor tracking capability to our radiation therapy program, with challenges.

Treatment delivery with InCise MLC has become more efficient, which made CK more practical in treating SRS, SBRT and IMRT.

We have explored different approaches in performing CK QAs.

SUMMARY

Charles Shang, Lynn Cancer Institute; cshang@brrh.com