How many institutions plan to perform quantitative studies to estimate appropriate margins as part of their IMRT implementation?

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X-ray Guided IMRT David A. Jaffray, Ph.D. Radiation Physics Department Radiation Medicine Program Princess Margaret Hospital University Health Network Contributors Fang-Fang Yin Henry Ford Hospital, Detroit, MI G.

Haycocks Princess Margaret Hospital, Toronto, CA T. Craig Princess Margaret Hospital, Toronto, CA M.

1 X-ray Guided IMRT David A. Jaffray, Ph.D. Radiation Physics Department Radiation Medicine Program Princess Margaret Hospital University Health Network Contributors Fang-Fang Yin Henry Ford Hospital, Detroit, MI G. Olivera Tomotherapy, Middleton, WI J. Pouliot UCSF, San Francisco, CA P. Munro Varian Medical Systems, Palo Alto, CA J. Wong William Beaumont Hospital, Royal Oak, MI T. Haycocks Princess Margaret Hospital, Toronto, CA T. Craig Princess Margaret Hospital, Toronto, CA M. Herman Mayo Clinic MGH AAPM 2003 Varian Summer Lecture, School COS Implementation of Intensity Modulated Radiation Therapy A lot of old baggage that seems to need resorting. Arising from: A new found capacity to generate and place dose gradients. A desire to avoid normal structures for complication reduction and/or dose escalation. Putting significant pressure on the margins that we have been using in conventional RT (both CTV and PTV/PRV). Heightening the need for an approach that can provide confidence in the PTV margin. Herring DF, Compton DMJ: The degree of precision required in the radiation dose delivered in cancer radiotherapy Brit J Radiol 5: , 1970 Recommends that the dose delivered over the course of treatment be known to within ± 5%. Achieving this level of accuracy and precision requires that each step of the treatment process performs at a dosimetric precision much better than 5%. This places stiff tolerances on both (i) the precision of the clinical dosimetry and (ii) the geometric precision in delivery and planning. To achieve and maintain the desired level of precision, it is recommended that a system of treatment delivery be constructed considering dosimetric and geometric factors. IMRT System Components Prescription Method Structure Definition (target and normal) Setup Aids & Immobilization Devices Breast boards, masks, ABC Positioning strategy Off-line and/or on-line evaluation and correction Imaging or Other Data Intervention Delivery Technique (gradients, delivery time, gating, tracking) Quality Assurance Checks Residual Geometric Uncertainty PTV Margins Recognizing the Broad Role of Physicists in Radiation Therapy TG-40, Kutcher et al. (1994) 1

2 How many institutions have quantitative support for their CTV to PTV margin? How many institutions plan to perform quantitative studies to estimate appropriate margins as part of their IMRT implementation? Patient and Process QA is Challenging Define the objectives up front. Constrain the process. Data-driven approach. Need integrated tools to analyze the data Requires a method of maintaining/monitoring performance. Dosimetry Chambers Electrometers Film/Scanners Diodes/Arrays Calib. Services Record Keeping Tools QA Tools of the Trade Mechanicals Levels Mechanical Gizmos Service/Support Film QA Phantoms Record Keeping Tools Geometric Delivery Precision Portal Films EPIDs CT-Sims Analysis Tools? Decision Tools? Margin Tools? Databases? Margin Estimation Tools Currently no commercial tools for this purpose. Recommended reading: Inclusion of geometric uncertainties in treatment plan evaluation. (van Herk et al.) Int J Radiat Oncol Biol Phys Apr 1;52(5): An off-line strategy for constructing a patientspecific planning target volume in adaptive treatment process for prostate cancer. (Yan et al.) Int J Radiat Oncol Biol Phys Aug 1;48(1): 2

Imports RTOG Format Margin Calculator T. Craig, Ph.D.

Confidence limit Simulation type Electronic Portal Imaging Systems

8 mm @ iso ~25 cm FOV multiple frames/sec Synchronized readout to

and analysis Varian s PortalVision as500 Employs CERR2, Deasy et al.

Data Lines Bias Line FET Control Lines One Pixel Bias Line Data Line

19: 1455-1466 (1992) Contact Pads External Charge Sensitive Pre-amp

3 Imports RTOG Format Margin Calculator T. Craig, Ph.D. Uncertainty distributions Target volume Dose distribution Dose goal Confidence limit Simulation type Electronic Portal Imaging Systems Metal plate, Gd 2 O 2 S:Tb iso ~25 cm FOV multiple frames/sec Synchronized readout to reduce banding artifacts Motorized support arm Integrated acquisition and analysis Varian s PortalVision as500 Employs CERR2, Deasy et al. Slide 13 Elekta - iview GT a-si:h Schematic a-si:h FET a-si:h Sensor Data Lines Bias Line FET Control Lines One Pixel Bias Line Data Line Photodiode Antonuk,et al Med.Phys. 19: (1992) Contact Pads External Charge Sensitive Pre-amp TFT Switch Gate Line as500 Flat Panel Perkin-Elmer Prototype Panel (20 cm x 20 cm) Gate Drivers Signal ASICs Courtesy of Rolf Stähelin - Varian, Baden 18MV, 15 MU 3

Lateral Pelvis Varian - 6 MU, 18 MV 18 MV 16 MU Courtesy of Herman, M., Kruse, J. et al.

J.Radiol. 31: 227 (1958) H.E. Johns et.al., Am.J.Roentgenol. 81: 4-12 (1959) Weissbluth et.al., Radiology 72: 242-253 (1959) L.

al., IJROBP 11: 635-643 (1985) R. Sephton et.al., Radiother.Oncol.

4 Lateral Pelvis Varian - 6 MU, 18 MV 18 MV 16 MU Courtesy of Herman, M., Kruse, J. et al. - Mayo Clinic Courtesy Jon Kruse - Mayo kv Sources for Guidance a.k.a. Back to the Future A.F. Holloway, Brit.J.Radiol. 31: 227 (1958) H.E. Johns et.al., Am.J.Roentgenol. 81: 4-12 (1959) Weissbluth et.al., Radiology 72: (1959) L.M. Shevron et.al., Clin.Radiol. 17: (1966) H.P. Culbert et.al. IJROBP 10 Sup 2: 180 (1984) P.J. Biggs et.al., IJROBP 11: (1985) R. Sephton et.al., Radiother.Oncol. 35: (1995) kv Portal Imaging on a 60 Co Unit X-otron PMH/OCI X-ray Tube Housed in the Head H.E. Johns et al.(1959) kv Portal Imaging on a Clinac-18 Room-based kv Localization Brain Lab Exac-trac Henry Ford Hospital Cyberknife System Stanford, Ca Shirato et al., Hokkaido University School of Medicine, Japan. Biggs et.al. IJROBP (1985) 4

BrainLAB ExacTrac/Novalis Image Guidance System - Calibration Image-Guided Extracranial Target Localization Calibration

DRRs Automatic comparison of live X-ray images with DRRs Iso-center reproducibility based on the imaging system is within 1mm.

Image-guided Radiosurgery Accuray - Cyberknife 1. Ceiling mounted x-ray tubes. 2.

Radiographic imaging up to 2 times per minute. 5. Fast automated DRRbased registration algorithm (bone or markers).

Int J Rad Oncol Biol Phys 55(5) 2003 Range of Corrections by Anatomical Region Cranial Bony Anatomy 0.

85 mm Discrepancy = shift Lung and Pancreas Markers (4 Au Markers + BH) 1-3 mm T x Thoracic and Lumber Spine Markers (4 Au

5 BrainLAB ExacTrac/Novalis Image Guidance System - Calibration Image-Guided Extracranial Target Localization Calibration Phantom Referenced to Isocenter Ceiling Mounted X-ray Tubes X-Ray acquisition on treatment couch Computerized generation of DRRs Automatic comparison of live X-ray images with DRRs Iso-center reproducibility based on the imaging system is within 1mm. FPI 20.5 x 20.5 cm 2 Yin et al., Henry Ford Hospital, Detroit, MI Pos. 1 Pos. 2 Live X-Rays DRRs Cyberknife - Accuray Inc. Image-guided Radiosurgery Accuray - Cyberknife 1. Ceiling mounted x-ray tubes. 2. X-band Accelerator on Robotic Positioning Unit. 3. Dual FPIs mounted opposite ceilingmounted x-ray tubes. 4. Radiographic imaging up to 2 times per minute. 5. Fast automated DRRbased registration algorithm (bone or markers). Localization precision: 1 s.d.: 0.7mm, 0.9 o Murphy et al. Int J Rad Oncol Biol Phys 55(5) 2003 Range of Corrections by Anatomical Region Cranial Bony Anatomy 0.85 mm Accuray - Cyberknife I T x I T x I t seconds Cervical Spine Bony Anatomy 0.85 mm Discrepancy = shift Lung and Pancreas Markers (4 Au Markers + BH) 1-3 mm T x Thoracic and Lumber Spine Markers (4 Au Markers) 0.86 mm Real-time Tumor-tracking System for Gated Radiotherapy Highly Integrated System (4 x- ray tubes, 4 Image Intensifiers) Temporal Resolution: 30 fps Spatial Targeting Precision: mm/s Murphy et al. Int J Rad Oncol Biol Phys 55(5) 2003 Shirato H et al., Hokkaido University School of Medicine, Sapporo, Japan. 5

Soft-tissue Imaging of Internal Structures Guide

Stronger correlation between imaged contrasts and

patients with Ca Lung): With real-time gating: 2.5-5.

cone-beam flat-panel kv and MV) In-room Conventional

Positional Accuracy: 0.2 mm (LAT) 0.18 mm (VERT) 0.

55(2) Feb 2003 Onishi et al. Int.J.Rad.Onc.Biol.Phys.

6 Soft-tissue Imaging of Internal Structures Guide therapy according to internal softtissue anatomy. Stronger correlation between imaged contrasts and target anatomy. Range of motion w.r.t. Tx port (4 patients with Ca Lung): With real-time gating: mm Without real-time gating: mm Shirato H et al., Hokkaido University School of Medicine, Sapporo, Japan. Computed Tomography (kv conventional, MV conventional, cone-beam flat-panel kv and MV) In-room Conventional CT for IGRT In-room Conventional CT for IGRT Positional Accuracy: 0.2 mm (LAT) 0.18 mm (VERT) 0.39 mm (LONG) Kuriyama et al. Int.J.Rad.Onc.Biol.Phys. 55(2) Feb 2003 Onishi et al. Int.J.Rad.Onc.Biol.Phys. 56(1) May 2003 CT Guidance Introduction to Helical Tomotherapy Portal-based Verification Onishi et al. Int.J.Rad.Onc.Biol.Phys. 56(1) May 2003 G. Olivera et al. Tomotherapy, Middleton, WI 6

University of Wisconsin TomoTherapy MVCT, 3 cgy University

Tomotherapy, Middleton, WI G. Olivera et al.

registration and fusion Automatic and/or manual registration

in Radiation Therapy Kilovoltage Jaffray et al.

Memorial Sloan Kettering, NY, NY Hesse et al.

7 University of Wisconsin TomoTherapy MVCT, 3 cgy University of Wisconsin TomoTherapy MVCT, 2.5 cgy G. Olivera et al. Tomotherapy, Middleton, WI G. Olivera et al. Tomotherapy, Middleton, WI Automatic and/or manual registration and fusion Automatic and/or manual registration and fusion Cone-beam Computed Tomography for Image Guidance in Radiation Therapy Kilovoltage Jaffray et al. - WBH/PMH Megavoltage Ford et al. Memorial Sloan Kettering, NY, NY Hesse et al. DKFZ, Heidelberg, Germany Pouliot et al. UCSF (with Siemens) Cone-Beam Computed Tomography (a) (b Robust 2D Detector Feasible Reconstruction Method 7

Bench-Top Cone-Beam CT System Processing of

15 mas) 120 kvp 2 mm Al + 0.127 mm Cu 14.

Exposure Normalization Pixel Defect Correction

Reconstruction Volume 1D FFT-based Hamming

Units Worldwide (Christie, WBH, PMH, NKI)

CT Imaging X-ray Image-Guided RT Feldkamp et al.

Calibration between imaging and delivery systems

8 Bench-Top Cone-Beam CT System Processing of Projection Data X-ray Exposure 50 ma, 3 ms (0.15 mas) 120 kvp 2 mm Al mm Cu 14.6 Cone Angle Detector Read-Out Gain and Offset Exposure Normalization Pixel Defect Correction 1024 x frames/sec (max) Object Rotation 300 Projections 1.2 per projection Repeat for 300 Projs. Geometry Filtered Back-Projection Log & Weight Reconstruction Volume 1D FFT-based Hamming Filter Σ 4x 2D Interpolation Elekta Synergy RP 4 Units Worldwide (Christie, WBH, PMH, NKI) Retractable kv X-ray Imaging System Volumetric CT Imaging X-ray Image-Guided RT Feldkamp et al. (1984) Repeat # of voxels # of projections Calibration between imaging and delivery systems X-ray Tube Mounted at 90 o Cone-beam CT Set of Head Phantom Product Release - May 2003 Transverse Sagittal Coronal Accelerator-based Acquisition; 320 Projections; 120 kvp, 200 mas; 180 s. (0.25 x 0.25 x 0.25) mm 3 voxels Unit at William Beaumont Hospital Royal Oak, MI 8

Cone-beam CT of Human Thigh Cone-beam CT of Human Pelvis Acquisition Parameters: Patient: 70 yr old female FOV: ~25 cm

matrix 0.5 mm pitch 0.5 mm slice thickness D center = ~0.5 cgy AAPM 2003 Courtesy Summer School of Drs. - COSP.

Khoo, Christie Hospital, Manchester, UK Cone-beam CT of Head and Neck Head Cone-beam CT of Head and Neck Neck and Lung

5 mm cubic voxels D surface = ~3 cgy Original Prototype, SL01 - WBH (IDE) Original Prototype, SL01 - WBH (IDE) Cone-beam

9 Cone-beam CT of Human Thigh Cone-beam CT of Human Pelvis Acquisition Parameters: Patient: 70 yr old female FOV: ~25 cm in diameter Reconstruction: 0.5 x 0.5 x 0.5 mm 3 T acq : 2 minutes (300 projections) Dose: ~1 cgy Elekta Synergy Research Platform Coronal Coronal 512 x 512 matrix 0.5 mm pitch 0.5 mm slice thickness D center = ~0.5 cgy AAPM 2003 Courtesy Summer School of Drs. - COSP. Williams and V. Khoo, Christie Hospital, Manchester, UK Courtesy of Drs. P. Williams and V. Khoo, Christie Hospital, Manchester, UK Cone-beam CT of Head and Neck Head Cone-beam CT of Head and Neck Neck and Lung 512 x 512 x 512 matrix 0.5 mm cubic voxels D surface = ~3 cgy 512 x 512 x 512 matrix 0.5 mm cubic voxels D surface = ~3 cgy Original Prototype, SL01 - WBH (IDE) Original Prototype, SL01 - WBH (IDE) Cone-beam CT of Head and Neck Axial 512 x 512 matrix 0.5 mm pitch 0.5 mm slice thickness D surface = ~3 cgy Conebeam CT Issues Detector field of view (~25 cm FOV, recon) Offset detector schemes Elevated x-ray scatter Noise and Cupping Artifacts Grids and algorithms Dynamic range of FPIs Driven by fluoroscopy applications in medicine Breathing motion during acquisition Original Prototype, SL01 - WBH (IDE) 9

Works-In-Progress On-Board Imaging Concept Works-In-Progress

$Fluoroscopic Interfraction Intrafraction On-Board Imaging Concept$ Cone-beam CT with a FPI.

S:Tb 1 frame/79 ms 12-bit ADC 500-1900 projections over 360 o Integer

Flat-Panel Comparison of MV FPI-CBCT Performance for MV and kv X-rays

05 PE 0.945 Water 1.00 Breast0.98 Brain 1.039 Resin 1.02 c 61.

10 Works-In-Progress On-Board Imaging Concept Works-In-Progress Preliminary CT Results Modes of operation Radiographic Cone Beam CT} Fluoroscopic Interfraction Intrafraction On-Board Imaging Concept ASTRO 2002 Images courtesy of Varian scientists and engineers MV Cone-beam CT with a FPI. Flat Panel Detector Hiemann RID 256-L 256 x 256, 800 um Cu/Gd 2 O 2 S:Tb 1 frame/79 ms 12-bit ADC projections over 360 o Integer number of x-ray pulses per projection. Flat-Panel Comparison of MV FPI-CBCT Performance for MV and kv X-rays a b MV: 6MV, Elekta SL20, kv: 100kVp, Elekta SL20 3 mm slice Liver 1.05 PE Water 1.00 Breast0.98 Brain Resin 1.02 c 61.3 cgy 26.7 cgy 5.8 cgy kv ~1.3 cgy kv Groh et al. Med. Phys CsI Screen 3600 mg/cm 2 Clinical Applications mm mm 8-9 mm 10

In-Room Radiographic Imaging for Localization

In-Room Radiographic Imaging for Localization Fang-Fang Yin, Zhiheng Wang, Sua Yoo, Devon Godfrey, Q.-R. Jackie Wu Department of Radiation Oncology Duke University Medical Center Durham, North Carolina