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RapidArc in Bergen

RapidArc in Bergen. Britt Nygaard, Harald Valen and Ellen Wasbø Haukeland University Hospital, Bergen, Norway. 2007: Trilogy with RapidArc option 2008: Scandidos Delta4 QA tool Aria upgrade: RapidArc on the Trilogy and 23iX Autumn 2009: Course in Bellinzona and Zug

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RapidArc in Bergen

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  1. RapidArc in Bergen Britt Nygaard, Harald Valen and Ellen Wasbø Haukeland University Hospital, Bergen, Norway

  2. 2007: • Trilogy with RapidArc option • 2008: • Scandidos Delta4 QA tool • Aria upgrade: RapidArc on the Trilogy and 23iX • Autumn 2009: • Course in Bellinzona and Zug • Stay-and-learn in Copenhagen • Eclipse AAA configuration • Machine QA and patient QA procedures • 2010: • Decisions, decisions.. Which category of patients? • Learning RapidArc doseplanning in Eclipse • 1st patient on 14th of June – 2nd on 22nd of November

  3. Quality control • Commisioning tests as suggested by Memorial Sloan-Kettering CC and Varian • A picket fence test during RapidArc • 7 adjacent fields with varying Dose rate & Gantry speed • 4 adjacent fields with varying MLC speed & Gantry speed • Possible to study combined effect of • dose rate and gantry speed • dynamic MLC and variable dose rate C. C. Ling et. al: Commissioning and Quality Assurance of RapidArc Delivery System. Radiotherapy, Int. J. Radiation Oncology Biol. Phys., Vol. 72, No. 2, pp. 575–581, 2008.

  4. MLC speed variation during RapidArc Dose rate and Gantry speed variation during RapidArc

  5. MLC speed variation (”Test3”) Dose rate and Gantry speed variation (”Test2”) Analyse results

  6. Clinac 23EX (2004): T2 & T3

  7. Trilogy (2007): T2 & T3

  8. Clinac 23iX (2005): T2 & T3

  9. TrueBeam (2011): T2 & T3

  10. Analyse results • Dynalog files • Log planned and actual leaf positions and leaf speed vs. time • Log gantry speed vs. Time • How TrueBeam • Tool: ”Analyse Dynalog” • In-house developed (EW) • Language: IDL

  11. Patient QA • Delta4 • Daily dose correction • Run and measure Verification plan • Pass / Fail criteria • Dose deviation • > 85% within ±3% deviation • Distance to agreement • > 98% with DTA ≤ 3mm • Gamma index 3%, 3mm • > 95% with index ≤ 1

  12. 1 arc, 135° to 225°, TrueBeam 6MV photons

  13. Clinac 23EX (2004), RapidArc in 2011: Failed T2 & T3 commissioning tests

  14. More patient QA • Independent dose calculation • Point check of dose • Control of monitor units

  15. Treatment planning, Autumn 2010: 5 yearsexperiencewith IMRT head and neck prostatewith and withoutlymph nodes (LN) ani (and gyn) with LN Sarcoma, lymphoma and other RA configuration and acceptance tests OK RA installedon 2 Clinacs Patient start up 17

  16. Which patient groups? Increased efficiency for the department Prostate with LN, 7 splitted fields Patients unable to keep the supine position for 10-15 min Head and neck Less MU and less risk for secondary cancer A category that is easy to create acceptable and standardized plans for Prostate intermediate risk 18

  17. Which patient groups? Increasedefficiency for thedepartment Prostatewith LN, 7 splittedfields Patientsunable to keepthesupineposition for 10-15 min Head and neck Less MU and less risk for secondary cancer A categorythat is easy to createacceptable and standardized plans for Prostateintermediate risk 19

  18. Prostate intermediate risk, criteria: Treatment of prostate and seminal vesicles Equal plan or better than IMRT (PTV and rectum) We made two plans, one IMRT (backup) and one RA, 1 arc 135-225° (avoid couch slides) for the 10 first patients PTV 95%-107%, median 100%, Rectum: max 10ml >60 Gy and less than 50 Gy to half the circumference Delta4 measurements OK; Gamma index 3%, 3mm > 95% with index ≤ 1 Dose deviation > 85% within ±3% deviation 20

  19. RA: 1 arc 135-225° 494 MU (2.15 Gy x 35) 5 fields IMRT: 574 MU (2.15 Gy x 35) 21

  20. RA: 1 arc 135-225° 494 MU (2.15 Gy x 35) 5 fields IMRT: 574 MU (2.15 Gy x 35 = 75.25) 22

  21. RA: 1 arc 135-225° 5 fields IMRT: 23

  22. IMRT RA 24

  23. RA today: (2.4 Gy sem.ves. and integrated boost 2.7 Gy prostate) x 25 = 67.5 Gy (EQD2= 81 Gy if α/β=1.5) 25

  24. 26

  25. Measured with Delta4 Gamma: 2mm 2% 27

  26. Prostate high risk: 2 Gy to the lymph nodes, integrated boost; 2.4 Gy sem.ves. and 2.7 Gy prost, 25 fractions 7 field-IMRT 1499 MU (2.7 Gy) 555 MU/Gy (calibration factor 130MU/Gy) 2 full arc RA 611 MU (2.7 Gy) 28

  27. RA IMRT 29

  28. IMRT RA 30

  29. Dose to rectum 31

  30. IMRT 32

  31. Future: We would like to treat our high risk protate with LN with two arcs Prerequisite: RA plan equal or better than IMRT (PTV and rectum) This autumn we have been focusing on commissioning TrueBeam.. 33

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