RapidArc in BergenBritt Nygaard, Harald Valen and Ellen WasbHaukeland University Hospital, Bergen, Norway

*2007: Trilogy with RapidArc option2008: Scandidos Delta4 QA toolAria upgrade: RapidArc on the Trilogy and 23iXAutumn 2009: Course in Bellinzona and ZugStay-and-learn in CopenhagenEclipse AAA configurationMachine QA and patient QA procedures2010:Decisions, decisions.. Which category of patients?Learning RapidArc doseplanning in Eclipse1st patient on 14th of June 2nd on 22nd of November

*Quality controlCommisioning tests as suggested by Memorial Sloan-Kettering CC and VarianA picket fence test during RapidArc7 adjacent fields with varying Dose rate & Gantry speed4 adjacent fields with varying MLC speed & Gantry speed

Possible to study combined effect of dose rate and gantry speeddynamic MLC and variable dose rateC. C. Ling et. al: Commissioning and Quality Assurance of RapidArc Delivery System. Radiotherapy, Int. J. Radiation Oncology Biol. Phys., Vol. 72, No. 2, pp. 575581, 2008.

*Dose rate and Gantry speed variation during RapidArc

*Analyse resultsMLC speed variation (Test3)Dose rate and Gantry speed variation (Test2)

Clinac 23EX (2004): T2 & T3

*Trilogy (2007): T2 & T3

*Clinac 23iX (2005): T2 & T3

*TrueBeam (2011): T2 & T3

*Analyse resultsDynalog filesLog planned and actual leaf positions and leaf speed vs. timeLog gantry speed vs. TimeHow TrueBeamTool: Analyse DynalogIn-house developed (EW)Language: IDL

*

*Patient QADelta4Daily dose correctionRun and measure Verification planPass / Fail criteriaDose deviation > 85% within 3% deviation Distance to agreement > 98% with DTA 3mmGamma 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 QADose dev. within 3%DTA < 3mm < 1 (3%, 3mm)PAB90,7%100%100%GB83,7%100%100%TER95,8%100%99,4%GDG85,5%100%100%EKGP85,9%100%100%MS83,0%100%100%

*More patient QAIndependent dose calculationPoint check of doseControl of monitor units

*Treatment planning, Autumn 2010:5 years experience with IMRThead and neckprostate with and without lymph nodes (LN)ani (and gyn) with LN Sarcoma, lymphoma and otherRA configuration and acceptance tests OK RA installed on 2 Clinacs Patient start up

*Which patient groups?Increased efficiency for the department Prostate with LN, 7 splitted fieldsPatients unable to keep the supine position for 10-15 minHead and neckLess MU and less risk for secondary cancerA category that is easy to create acceptable and standardized plans forProstate intermediate risk

*Which patient groups?Increased efficiency for the department Prostate with LN, 7 splitted fieldsPatients unable to keep the supine position for 10-15 minHead and neckLess MU and less risk for secondary cancerA category that is easy to create acceptable and standardized plans forProstate intermediate risk

*Prostate intermediate risk, criteria:Treatment of prostate and seminal vesiclesEqual 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 patientsPTV 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 1Dose deviation > 85% within 3% deviation

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

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

*5 fields IMRT:RA: 1 arc 135-225

*IMRTRA

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

*

*Gamma: 2mm 2%Measured with Delta4

*7 field-IMRT1499 MU (2.7 Gy)555 MU/Gy (calibration factor 130MU/Gy)2 full arc RA611 MU (2.7 Gy)Prostate high risk: 2 Gy to the lymph nodes, integrated boost; 2.4 Gy sem.ves. and 2.7 Gy prost, 25 fractions

*IMRTRA

*IMRTRA

*Dose to rectum

*IMRT

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

*****Ttest2:MU/min/sMU/Red: 105 4.8 0,364Drk Green: 2094.80,727Violet:3144.81,091Blue:4194.81,455White: 5234.81,818Pink:5884.82,045Green:6004.42,273

Ttest3:MU/min/sMU/Rd: 480 4.8 1.667Grnn: 6004.02.5Lilla:2404.80.833Bl:1204.80.417

**************Dose difference 3%, histogram centered around 0

*****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.

*1.9 cm, limit 2.6cm*******121 pasienter med RA prost +1 ca penis med paraaortale lkn og lysker 1 lymfom i buken1 vesica

*