RapidArc in Bergen

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RapidArc in Bergen

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

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• 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

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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. 575581, 2008.
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Dose rate and Gantry speed variation during
RapidArc
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Analyse results

• Dose rate and Gantry speed variation (Test2)

• MLC speed variation (Test3)

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Clinac 23EX (2004) T2 T3
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Trilogy (2007) T2 T3
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Clinac 23iX (2005) T2 T3
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TrueBeam (2011) T2 T3
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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

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Patient QA

• Delta4
• Daily dose correction
• Run and measure Verification plan
• Pass / Fail criteria
• Dose deviation
• gt 85 within 3 deviation
• Distance to agreement
• gt 98 with DTA 3mm
• Gamma index 3, 3mm
• gt 95 with index 1

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1 arc, 135 to 225, TrueBeam 6MV photons
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Clinac 23EX (2004), RapidArc in 2011 Failed T2
T3 commissioning tests
Patient QA Dose dev. within 3 DTA lt 3mm ? lt 1 (3, 3mm)
PAB 90,7 100 100
GB 83,7 100 100
TER 95,8 100 99,4
GDG 85,5 100 100
EKGP 85,9 100 100
MS 83,0 100 100
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More patient QA

• Independent dose calculation
• Point check of dose
• Control of monitor units

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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

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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

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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

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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 gt60 Gy and less than 50 Gy to
  half the circumference
• Delta4 measurements OK
• Gamma index 3, 3mm
• gt 95 with index 1
• Dose deviation
• gt 85 within 3 deviation

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RA 1 arc 135-225 494 MU (2.15 Gy x 35)
5 fields IMRT 574 MU (2.15 Gy x 35)
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RA 1 arc 135-225 494 MU (2.15 Gy x 35)
5 fields IMRT 574 MU (2.15 Gy x 35 75.25)
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RA 1 arc 135-225
5 fields IMRT
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IMRT
RA
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RA today (2.4 Gy sem.ves. and integrated boost
2.7 Gy prostate) x 25 67.5 Gy (EQD2 81 Gy if
a/ß1.5)
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Measured with Delta4
Gamma 2mm 2
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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)
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IMRT
RA
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IMRT
RA
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Dose to rectum
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IMRT
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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..

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