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

2007: 2008: Autumn 2009: 2010: Trilogy with RapidArc option 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

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.

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

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

Clinac 23EX (2004): T2 & T3 Ttest2: MU/min °/s MU/° Red: 105 4.8 0,364 Drk Green: 209 4.8 0,727 Violet: 314 4.8 1,091 Blue: 419 4.8 1,455 White: 523 4.8 1,818 Pink: 588 4.8 2,045 Green: 600 4.4 2,273 Ttest3: Rød: 480 4.8 1.667 Grønn: 600 4.0 2.5 Lilla: 240 4.8 0.833 Blå: 120 4.8 0.417

Trilogy (2007): T2 & T3

Clinac 23iX (2005): T2 & T3

TrueBeam (2011): T2 & T3

Analyse results Dynalog files Tool: ”Analyse Dynalog” 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

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

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

Clinac 23EX (2004), RapidArc in 2011: Failed T2 & T3 commissioning tests Patient QA Dose dev. within ±3% DTA < 3mm γ < 1 (3%, 3mm) PAB 90,7% 100% GB 83,7% TER 95,8% 99,4% GDG 85,5% EKGP 85,9% MS 83,0%

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

Treatment planning, Autumn 2010: 5 years experience with IMRT head and neck prostate with and without lymph nodes (LN) ani (and gyn) with LN Sarcoma, lymphoma and other RA configuration and acceptance tests OK RA installed on 2 Clinacs Patient start up 17

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

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 19

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 Dose difference 3%, histogram centered around 0 20

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

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

5 fields IMRT: RA: 1 arc 135-225° 23

IMRT RA 24

RA today: (2. 4 Gy sem. ves. and integrated boost 2 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) Today we use 6MVX, more MU (+6%) than with 15MVX but no neutrons. Ca 620 MU for 2.7 Gy (Calibration 130 MU 10*10 field 10 cm depth equals 1Gy) We use implanted gold markers and we have got IGRT-couch in the calculation. 25 25

1.9 cm, limit 2.6cm 26 26

Measured with Delta4 Gamma: 2mm 2% 27 27

Prostate high risk: 2 Gy to the lymph nodes, integrated boost; 2 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

IMRT RA 29

IMRT RA 30

Dose to rectum 31

IMRT 32

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.. 121 pasienter med RA prost + 1 ca penis med paraaortale lkn og lysker 1 lymfom i buken 1 vesica 33