Head and Neck Treatment Planning: A Comparative Review of Static Field IMRT RapidArc TomoTherapy HD Barbara Agrimson, BS RT(T)(R), CMD
Disclaimer This presentation will mention equipment by trade name. This does not mean that I endorse the product but rather mention it because it is used at my facility.
Objectives of Presentation To review the evolution of head and neck planning at Oregon Health Sciences University (OHSU) since 2005. To share basic contouring techniques of the head and neck area. To learn the planning approach of head and neck cancers at OHSU using static field IMRT, Varian RapidArc, and TomoTherapy. To identify similarities and differences between static field IMRT, Varian RapidArc, and TomoTherapy, for head and neck treatment plans.
I. Review the evolution of head and neck planning.
The Planning Evolution Evolution of Head and Neck Treatment 2005: Static Field IMRT Varian 21ex Pinnacle TPS Impac RVS 2007: Varian Upgrade Varian Trilogy CBCT Eclipse TPS Aria RVS 2008 paperless
The Planning Evolution Evolution of Head and Neck Treatment 2010: Rapid Arc Varian Trilogy Eclipse TPS Aria RVS
The Planning Evolution Evolution of Head and Neck Treatment 2011: TomoTherapy Tomo HD How do plans compare? Downtime TomoTherapy TPS Learning curve Plan quality? Outcome Generate plans for comparison» Staff acceptance Backup plans?» Downtime
The Planning Evolution Evolution of Head and Neck Treatment 2015 Planning Systems Eclipse TomoTherapy TPS Pinnacle Monaco Treatment Machines Varian HD TomoTherapy Elekta Record and Verify MOSIAQ
Current OHSU Status Three options for patients with head and neck cancers
Current OHSU Status Most head and neck cancer patients are scheduled on TomoTherapy Approximately 100 HN patients treated each year Requires one TomoTherapy plan plus one backup plan of equal quality. Dosimetrist can choose RapidArc (VMAT), IMRT or both, for back-up plan. Physician will select the most appropriate plan for treatment Plan comparison Objectives Imaging Treatment time Machine work-load
Current OHSU Status From simulation to patient start date ~ 4-6 working days. Plan must be completed in dosimetry two days before the patients initial treatment. Dosimetrist Registers requested ancillary imaging; PET, MRI, CT Contours all structures in Eclipse; OAR and planning structures. All structures needed for treatment planning are contoured in Eclipse Physician Reviews the registration and OAR contours Contours the CTV and PTV volumes Generates the planning objectives form EPIC note or email
Current OHSU Status Contours and CT dataset are exported to TomoTherapy, Pinnacle, or Monaco TPS for planning. Plans are generated simultaneously in TomoTherapy and Pinnacle. We are still learning the Monaco planning system. Physician evaluates completed plans Approves one plan for treatment Back-up plan will also be approved if TomoTherapy is the primary treatment Physics QA done on both plans
II. Contouring
Head and Neck Contours CT scan Philips Brillance Big Bore Contouring Eclipse v8.9 TPS with Wacom tablets
Wacom Tablet for Contouring in Eclipse and Planning
Dental Artifact! =
Raw CT data set O-MAR Processed
Better = Dataset after using Philips O-MAR software function.
Common Anatomy Contoured Spinal Cord Cord+5mm Brainstem Brainstem+5mm Eyes Lens Optic nerves Mandible Parotids Cochlea's Submandibular glands Hyoid Larynx Constrictors Cervical Esophagus Lips (sometimes)
Target Contours GTV GTV + margin = PTV High Dose (Hot Spot Here) CTV1 Primary lymph node chain CTV1+3 mm = PTV1 CTV2 Seconday Lymph node chain CTV2+3 mm = PTV2 2-3 mm margin between skin surface and PTV volumes Helps to prevent severe acute skin reaction and late fibrosis of subcutaneous tissue
GTV Delineation using multiple imaging modalities Planning CT MRI PET scan
RTOG Contouring Atlas
Contours
Target Volumes CTV1 GTV CTV2
Artifact and Density Override
OAR/Target Overlap
Contouring Planning structures Dose Ring Wall Extraction tool 3mm margin 1 cm wide Control dose
Contouring Planning structures Normal Tissue Ring Copy Body Crop out of PTV with additional 1.5 cm margin Control dose
Contouring Planning structures Posterior Avoid Posterior expansion of the Cord+5mm Limit dose to posterior neck region
III. Planning Part A
Prescription Prescription (typical case) 100% isoline to cover 95% of the target volume (PTV high dose) Target and 2 nodal dose levels 200 cgy x 35 = 70 Gy PTV High Dose 180 cgy x 35 = 63 Gy PTV63 160 cgy x 35 = 56 Gy PTV56
Prescription OAR objectives Planning objectives form ( Love Note ) Planning OAR techniques Upper/lower PTV In air/ in tissue PTV s Subtract overlap OAR s from PTV s No margin
Planning Objectives (Case Specific) Dosi Love Note Cord < 45 Gy Cord+5mm < 50 Gy Brainstem < 50 Gy Brainstem+5mm<55 Gy Mandible ~ max < 70 or 72Gy No more than 5%>70 Gy Parotids L Parotid mean < 26 Gy R Parotid mean < 22 Gy
Planning Objectives (Case Specific) Dosi Love Note Hyoid max < 74 Gy Larynx mean < 60 Gy Constrictors mean < 50 Gy Cervical Esophagus mean < 35 Gy, max < 65 Gy Cochlea's R cochlea mean < 12 Gy L cochlea mean < 7 Gy
Miscellaneous Factors Patient specific Patient supine, halcyon board, aquaplast mask, "B headrest, shoulder retractors, knee sponge. Align bilateral and anterior bb's on mask with anterior chest tattoo. Shoulders Avoidance contours with TomoTherapy plans. Couch kick ~15 degrees with IMRT beams that may enter through shoulders. Arc sections for shoulders with full arc rotations.
Miscellaneous Factors Back-up plans Required with patients treated on the TomoTherapy machine Machine down time Imaging challenges Physician approves both TomoTherapy and optional plan Both plans are printed and require physics QA and therapist verification Only one charge is billed for that case. Dosimetry work flow Simultaneous planning between TomoTherapy and optional planning systems One Dosimetrist can work on TomoTherapy plan while another works on the other plan.
Miscellaneous Factors Department Splitting work load between machines Imaging The Physician will factor in the imaging quality of the machine when deciding the treatment machine for the patient. MVCT Daily on TomoTherapy kv CBCT Daily on Linac kv orthogonal pair As back-up, if needed Exactrac More complex OAR locations Field limitations
kv CBCT versus MV CT
III. Planning Part B
Planning Specifics Static Field IMRT RapidArc (VMAT) TomoTherapy
Static IMRT Planning 9 Field beam arrangement 2 non-coplanar to avoid shoulders Sliding window delivery Collimator rotation Typically no rotation Beam energy 6 MV Unique planning contours Posterior neck avoidance Tissue Rings Dose hot spots Planning objectives 100% of dose to cover 95% of target volume
Planning Contours
Beam arrangement 2 full, 1 partial arc Field width of 15 cm total Collimator rotation 10 degrees CW and CCW Beam energy 6 MV Unique planning contours PTV in air/in tissue PTV superior/inferior Planning objectives 100% of dose to cover 95% of target volume RapidArc Planning
TomoTherapy Planning Jaw selection Pitch 1cm field width at beam batch.287 Regular verses Fine dose calculation Less degradation Takes longer to batch Longer optimization time Unique planning contours Separate out overlying structures to the PTV s Planning objectives 100% of dose to cover 95% of target volume Model after the Eclipse DVH
Overlap OAR s Overlap Priority built into planning software Not our preferred method based on physician expectation Utilize sub structures Optimize to these cropped structures Improves target coverage
TomoTherapy Planning Jaw Setting Delivery Time R Cochlea L Cochlea PTV coverage Sup/Inf slices 2.5 cm Width 6.3 min 2068 cgy 2183 cgy Marginal 1 cm Width 13.8 min 1435 cgy 1736 cgy Improved
Head and Neck Delivery Time Average Treatment Time 9 field IMRT ~ 15 minutes RapidArc (2 or 3 arc) ~ 3-6 minutes TomoTherapy ~ 12 minutes (1.0 cm Jaw setting) 6 minutes (2.5 cm Jaw setting) Average Daily Image Guidance 9 field IMRT ~ 5 minutes RapidArc (2 or 3 arc) ~ 5 minutes TomoTherapy ~ 3 minutes (Volume < 30 slices)
Head and Neck Comparison How is the best plan selected? Maximum Dose (Hot Spot location) Conformality Homogeneity Target coverage OAR doses Trade-offs of each plan
How many letter F s do you see? FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS
IV. Comparative Case Studies
Case #1: Unilateral HN 49 y.o. woman with T2N0 SCC of R oral tongue s/p hemiglossectomy and neck dissection 3 dose regions PTV 60 Gy PTV 56 Gy PTV 50 Gy RTOG 0920 protocol
Case #1: Unilateral HN Dose Comparison (cgy) Static IMRT RapidArc TomoTherapy Max Dose 6945 (116%) 6631 (111%) 6549 (109%) Max Spinal Cord 3900 3987 4054 Mean L Parotid 1622 1082 1088 Mean R Parotid 3298 3583 3389 Max Mandible 6574 6491 6250 Mean L Cochlea 172 194 218 Mean R Cochlea 198 189 388
Case #1: Unilateral 8000 7000 6000 5000 Dose (cgy) 4000 3000 Static IMRT RapidArc Tomotherapy 2000 1000 0 Max Dose Max Spinal Cord Mean L Parotid Mean R Parotid Max Mandible Mean L Cochlea Mean R Cochlea Structure
Static IMRT TomoTherapy RapidArc
Case #2: Bilateral HN 69 y.o. male with T4N1M0 SCC of L BOT Concurrent cetuximab 3 dose regions PTV 70 Gy PTV 63 Gy PTV 56 Gy
Case #2: Bilateral HN Dose Comparison (cgy) Static IMRT RapidArc TomoTherapy Max Dose 7870 (112%) 7646 (109%) 7267 (104%) Max Spinal Cord 4424 4396 4182 Mean L Parotid 3345 3568 3654 Mean R Parotid 2749 2218 2103 Max Mandible 7870 7465 7153 Mean L Cochlea 1808 2223 3028 Mean R Cochlea 1357 1269 1511
Case #2: Bilateral 9000 8000 7000 6000 Dose (cgy) 5000 4000 Static IMRT RapidArc Tomotherapy 3000 2000 1000 0 Max Dose Max Spinal Cord Mean L Parotid Mean R Parotid Max Mandible Mean L Cochlea Mean R Cochlea Structure
Static IMRT TomoTherapy RapidArc
Case #3: Bilateral HN 61 y.o. male with T4N2c SCC of BOT Concurrent cisplatin 3 dose regions PTV 70 Gy PTV 63 Gy PTV 56 Gy
Case #3: Bilateral HN Dose Comparison (cgy) Static IMRT RapidArc TomoTherapy Max Dose 7706 (110%) 7936 (113%) 7377 (105%) Max Spinal Cord 4476 4530 4147 Mean L Parotid 3865 4032 3842 Mean R Parotid 4889 4462 4909 Max Mandible 7642 7807 7225 Mean L Cochlea 765 441 460 Mean R Cochlea 880 701 1335
Case #3: Bilateral 9000 8000 7000 6000 Dose (cgy) 5000 4000 Static IMRT RapidArc Tomotherapy 3000 2000 1000 0 Max Dose Max Spinal Cord Mean L Parotid Mean R Parotid Max Mandible Mean L Cochlea Mean R Cochlea Structure
Static IMRT TomoTherapy RapidArc
Case #4: Bilateral HN 49 y.o. male with T2aN1M0 pleomorphic rhabdomyosarcoma of the BOT Concurrent ifosfamide 2 dose regions PTV 67.5 Gy PTV 60 Gy
Case #4: Bilateral HN Dose Comparison (cgy) Static IMRT RapidArc TomoTherapy Max Dose 7451 (110%) 7324 (109%) 7019 (104%) Max Spinal Cord 4092 4473 4117 Mean L Parotid 2895 2837 2849 Mean R Parotid 2655 2486 2491 Max Mandible 7451 7205 7008 Mean L Cochlea 454 448 584 Mean R Cochlea 395 368 405
Case #4: Bilateral 8000 7000 6000 5000 Dose (cgy) 4000 3000 Static IMRT RapidArc Tomotherapy 2000 1000 0 Max Dose Max Spinal Cord Mean L Parotid Mean R Parotid Max Mandible Mean L Cochlea Mean R Cochlea Structure
Static IMRT TomoTherapy RapidArc
General Conclusions Non-TomoTherapy plans tend to run hotter overall Especially RapidArc RapidArc shares similarities to both IMRT and TomoTherapy depending on structure Middle child TomoTherapy contributes higher dose to cochlea and other structures above or below the PTV. Dynamic jaw upgrade is helpful for this.
General Conclusions Unilateral disease Better with static IMRT Sparing of contralateral neck 7 field beam arrangement Bilateral disease Better with TomoTherapy Conformality Maximum dose lower RapidArc is a beautiful plan but often the maximum dose is too high.
Situations We ve Experienced Patient switching between machines Dose tracking VelocityAI 2.7.0 Composite Plans Adaptive planning Maintain the same treatment machine for consistency.
In Conclusion First we began planning with 9 field static beam IMRT And it was good, much better than 3D! Next we added RapidArc planning and we had options And often it was a better plan. Then we branched out and began TomoTherapy planning. Now we offer a well rounded option for the physician to evaluate. The end result is improved treatment plans for our patients. As of March 2015, we no longer run two plans. Instead, the Physician selects the treatment machine at time of simulation and we plan accordingly.
Acknowledgements Special thanks to Dr. John Holland for sharing insight concerning key aspects of head and neck cancer treatments. Steven Rhodes my coworker who helped me put together this presentation. Reference material was obtained from the American Cancer Society and The National Cancer Institute. OHSU Radiation Therapy students class of 2015, who offered me presentation feedback. Any Therapy positions available for RT graduates?
Answer is 6. Not everything is apparent the first time through FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS
Thank you