Varian _ Dynamic Targeting TM Image-Guided Radiation Therapy

Varian _ Dynamic Targeting. TM Image-Guided Radiation Therapy Scott Johnson, Ph. D Varian Medical Systems Palo Alto, California

Varian IGRT Statistics n As of the end of Dec, Varian had booked 80 orders for the On-Board Imager (OBI) n As to today, 35 installations have been completed n n And another dozen installations currently are in progress As of today, cone-beam CT software has been installed at 7 sites n Aarau, Switzerland n Karolinska, Sweden n MSKCC, New York n Emory, Atlanta n Stanford, Palo Alto n Duke, Durham n Henry Ford, Detroit n With an additional installations scheduled in the very near future n MD Anderson, Houston VARIAN medical systems Page 2

What is IGRT? n IGRT means several things … n Use of images for online setup correction, before treatment begins n n Position patient on table. Align the patient to lasers. Acquire images n n n Compare the acquire images to reference images n n n Images usually are k. V Images may be an orthogonal pair of radiographs or a volumetric image (e. g. , cone-beam CT) Analysis may be automated and/or manual Analysis may rely on radiopaque markers, bony anatomy or soft-tissue anatomy Result of the analysis is data on how to correct the patient position Move the treatment couch remotely to automatically correct the patient position Optional: Acquire and analyze another set of images to verify the correction Begin treatment delivery VARIAN medical systems Page 3

Movie of the clinical process VARIAN medical systems Page 4

What is IGRT? n Use of images for online setup correction, before treatment begins n What’s new here: n Use of k. V imaging in the treatment room n New image analysis tools for therapist n Fast, easy to use, integrated into the existing workflow Remote couch control, to speed the process The result is: n Significant improvement in target localization n n Reduced likelihood of missing the target An opportunity to reduce CTV-to-PTV margins and thus the volume of normal tissue irradiated to high dose n May reduce the toxicity of RT VARIAN medical systems Page 5

What is IGRT? n IGRT also may mean adaptive radiation therapy n Tumors, hopefully, respond to treatment and shrink over the course of therapy n As the surrounding tissues are pulled inward, the result may increase the dose to critical structures n With adaptive RT, goal is to use images to n Perform online setup correction of patient position n Acquire a volumetric image (cone beam CT scan) n Automatically detect any changes in the target shape n Automatically adapt the treatment plan to reflect the new target shape n Provide therapist with important information on how the plan has changed n Deliver the new plan n (It’s kind of like a boost plan, but done online with the patient on the table) n Above process should occur within 15 -20 minutes, or less VARIAN medical systems Page 6

What is IGRT? n With adaptive radiation therapy, images of the tumor size, shape and location are used to adapt the treatment plan before it is delivered Critical structure Target Prescription isodose Critical structure Original treatment plan and anatomy VARIAN medical systems Page 7

What is IGRT? n With adaptive radiation therapy, images of the tumor size, shape and location are used to adapt the treatment plan before it is delivered Critical structure Target Prescription isodose Critical structure Original treatment plan and new anatomy with tumor shrinkage due to radiation VARIAN medical systems Page 8

What is IGRT? n With adaptive radiation therapy, images of the tumor size, shape and location are used to adapt the treatment plan before it is delivered Critical structure Target Prescription isodose Critical structure Adapted treatment plan VARIAN medical systems Page 9

What is IGRT? n With adaptive radiation therapy, images of the tumor size, shape and location are used to adapt the treatment plan before it is delivered n No one is doing this yet! n Before it can be done, the following are needed n Ability to acquire CT scans on the treatment table. DONE! n Automated image segmentation tools that automatically contour the patient anatomy n New treatment plan analysis tools for therapist n n n Including tools that clear show what treatment plan adaptations are needed and what the effect of those changes is Fast, easy to use software that is well integrated into the existing treatment delivery process Guidelines on when adapted treatment plans should be reviewed by a physicist or physician Guidelines on how to QA the adaptive radiation therapy process Etc VARIAN medical systems Page 10

What is IGRT? n IGRT also can be considered to include dose guided radiation therapy n Acquire a CT scan of the patient on the treatment table in the treatment position n Deliver the treatment plan n Use an EPID to capture transit dose images or capture linac and MLC log files n Use transit dose to back project delivered dose onto CT or use log files to forward project delivered dose onto CT Dose actually emitted by the linac overlayed onto CT scan of patient on treatment table n The result is a realistic calculation of the dose delivered that day including the impact of bladder and rectal filling, bowel gas, etc VARIAN medical systems Page 11

What is IGRT? n IGRT also can be considered to include dose guided radiation therapy n Now, imagine repeating the above process at each treatment session and having the ability to morph the results onto each other n n Summing the results allows you to visualize the dose actually delivered to the target and critical structures over a series of treatment sessions With advanced treatment planning tools, you then may choose to adapt the treatment plan mid-stream so that the final, cumulative dose satisfies the physician’s prescription VARIAN medical systems Page 12

What is IGRT? n IGRT also can be considered to include dose guided radiation therapy n Again, no one is doing this yet, but we are getting close… n Before it can be done, the following are needed n Ability to acquire CT scans on the treatment table. DONE! n Ability to capture linac and MLC log files or transit dose. DONE! n Ability to project beams recorded in log files into CT scans. DONE! n Image and dose morphing tools that allow you to sum the dose to a volume over several sessions, given that the volume is changing size, shape and location n Fast, easy to use software that is well integrated into the existing treatment delivery process n Guidelines on when to adapt a plan and when that adapted plan should be reviewed by a physicist or physician n Guidelines on how to QA the dose guided radiation therapy process n Etc VARIAN medical systems Page 13

Will IGRT replace IMRT? n No, the two are complementary. n IMRT allows the dose to conform tightly to the PTV. n IGRT allows the PTV to shrink to the CTV. n IG-IMRT then allows simultaneously marginreduction and dose conformation. Conventional RT Organ at risk IMRT PTV CTV High dose isodose IG-IMRT VARIAN medical systems Page 14

Varian IGRT Technology On-Board Imager accessory Available as an upgrade to any Clinac installed in 1997 and after VARIAN medical systems Page 15

On-Board Imager n Hardware n n k. V Xray source n Amorphous silicon imaging panel n n Two robotic arms OBI workstation Three modes of operation n Radiographic n Online setup correction n n Bony anatomy or markers CBCT n Online setup correction n Bony or soft tissue anatomy n n n Visualization of delivered dose Trilogy and the On-Board Imager Adaptive radiation therapy Fluoroscopic n Verification of gated radiation therapy n Fluoro-based tumor tracking (*Future option) VARIAN medical systems Page 16

Command Center Clinac console, 4 D Console, OBI workstation, RPM Gating workstation VARIAN medical systems Page 17

Robotic arm motion VARIAN medical systems Page 18

Robotic arm motion VARIAN medical systems Page 19

Robotic arm motion VARIAN medical systems Page 20

Robotic arm motion VARIAN medical systems Page 21

Varian IGRT Technology Orthogonal radiographs for online patient setup correction VARIAN medical systems Page 22

Acquisition of a lateral radiograph VARIAN medical systems Page 23

Acquisition of an AP radiograph VARIAN medical systems Page 24

Sample radiographs Images courtesy of Karolinska Medial Center VARIAN medical systems Page 25

Sample radiographs Images courtesy of Karolinska Medial Center VARIAN medical systems Page 26

On-Board Imager workstation VARIAN medical systems Page 27

On-Board Imager workstation VARIAN medical systems Page 28

Marker matching using the On-Board Imager VARIAN medical systems Page 29

Marker matching using the On-Board Imager VARIAN medical systems Page 30

Varian IGRT Technology Cone beam CT for online patient setup correction (and adaptive radiation therapy and dose guided radiation therapy) VARIAN medical systems Page 31

Acquisition of a cone beam CT scan VARIAN medical systems Page 32

Acquisition of a cone beam CT scan VARIAN medical systems Page 33

Acquisition of a cone beam CT scan VARIAN medical systems Page 34

Acquisition of a cone beam CT scan VARIAN medical systems Page 35

Acquisition of a cone beam CT scan VARIAN medical systems Page 36

Acquisition of a cone beam CT scan VARIAN medical systems Page 37

Acquisition of a cone beam CT scan VARIAN medical systems Page 38

Sample CBCT image Images courtesy of Duke University Hospital VARIAN medical systems Page 40

Varian IGRT Technology Controlling for respiratory motion VARIAN medical systems Page 41

Respiratory gating n RPM Gating System n n External marker block n n Infrared camera Gating workstation Process n Place block on patient’s abdomen n Camera monitors block motion n Respiratory waveform shows how the block moves up and down in time n User sets upper and lower thresholds on block motion n Whenever the block comes between the thresholds, the beam is on n Whenever the block moves outside thresholds, the beam is off n Free-breathing and breath hold protocols are supported, as are gating at inhalation or exhalation or at any other point in the respiratory cycle VARIAN medical systems Page 42

Fluoro-based verification of gating With the On-Board Imager, gated k. V radiographs are used to verify patient setup and k. V fluoroscopy is used to verify the gated treatment port. VARIAN medical systems Page 43

VARIAN medical systems Page 44

VARIAN medical systems Page 45

VARIAN medical systems Page 46

VARIAN medical systems Page 47

Varian IGRT Technology What’s next? VARIAN medical systems Page 48

Where we are headed n New software tools for online adaptive radiation therapy and dose guided radiation therapy n n Automated segmentation of acquired CBCT scans Treatment planning and plan review tools at the Command Center Fast, automated plan modification tools New software tools for fluoro-based gating, in which the gating signal is based on the motion of internal anatomy (rather than an external marker block) VARIAN medical systems Page 49

Where we are headed n New MLC control system to enable real-time tumor tracking VARIAN medical systems Page 50

Varian IGRT Technology Why we think it is superior VARIAN medical systems Page 51

Varian’s IGRT technology Compared to Tomotherapy n We use k. V photons rather than MV for superior image quality n We use cone-beam CT rather than helical slice-based CT because cone-beam CT images are superior and CBCT is the future n Radiology, in general, is moving toward CBCT n n n 1 slice scanner > 2 slice > 4 slice > 8 slice > 16 slice > … Because of the exquisite detail, CBCT already has been adopted by Cardiology We can develop fluoro-based tools to monitor and control for respiratory motion n Tomotherapy will have a difficult time dealing effectively with respiratory motion VARIAN medical systems Page 52

Varian’s IGRT technology Compared to Novalis and Cyber. Knife n We use a gantry-based system, rather than a room-based system, to have the option of acquiring CBCT scans n Volumetic imaging is not possible with Novalis or Cyber. Knife VARIAN medical systems Page 53

Varian’s IGRT technology Compared to Synergy n We use robotic arms to position the k. V source and k. V imager to allow remote control and superior flexibility in imaging geometry n We use high-quality Varian imagers, which have a much higher image acquisition rate n Up to 30 frames per second, compared to 3 -5 frames per second for Elekta n Most clinicians feel that a frame rate of at least 12 -15 images/second is required for fluoro-based gating VARIAN medical systems Page 54

Conclusion n Varian offers the most integrated and comprehensive solution available n k. V radiographs n k. V/MV radiographs n Gated radiographs n Marker-based setup corrections, 2 D-2 D and 2 D-3 D n CBCT acquisition and analysis n Pretreatment verification of gated treatment ports n Robotic couch motion n IGRT software integrated with the VARi. S Vision Eclipse database n Varian is well-positioned to quickly deliver the next generation of IGRT technology VARIAN medical systems Page 55

Thank you VARIAN medical systems Page 56