First experiences and results karen feyen az st maarten duffel belgium
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First Experiences and Results Karen Feyen AZ St-Maarten Duffel , Belgium. A Cylindrical 3D Water Scanner –. A.Z. Sint-Maarten – RT department - Linacs. SLi 18 (installed 2002), conformal treatments 6MV/15MV photons 5 electron energies MLCi with 1 cm leaves, max field size 40 cm x 40 cm

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First experiences and results karen feyen az st maarten duffel belgium

First Experiences and Results

Karen Feyen

AZ St-Maarten Duffel, Belgium

A Cylindrical 3D Water Scanner –


A z sint maarten rt department linacs
A.Z. Sint-Maarten – RT department - Linacs

  • SLi 18 (installed 2002), conformal treatments

    • 6MV/15MV photons

    • 5 electron energies

    • MLCi with 1 cm leaves, max field size 40 cm x 40 cm

    • Short physics duct from control area to linac technical area : no fixed cabling

  • Synergy platform (installed 2007), IMRT

    • 6MV/15MV photons

    • Beam modulator with 4 mm leaves, max field size 21 cm x 16 cm

    • Physics duct about 25 m, fixed cabling and connectors in bunker and control area

  • EPID based IGRT on both systems

    • Iview GT

    • Vanderwilt remote table control

    • Offline/online protocols, no CBCT

  • ± 1000 new patients/year


A z sint maarten rt department
A.Z. Sint-Maarten – RT department

  • CT simulation

    • Siemens Definition CT (medical imaging department)

    • A2J CT-Sim lasers

    • Medio 50 CP simulator used for some palliative

    • Medio 50 CP simulator

    • Some palliative treatments

  • Main TPS = Pinnacle

  • Brachy:

    • Nucletron HDR / Oncentra Masterplan

    • PBT inhouse/other centers : Bard / Variseed

  • Other equipment

    • More than 40 PC’s and workstations for about 20 people

    • A lot of cables and a lot of heat


Dosimetry material
Dosimetry material

  • Abolute Dosimetry

    • FC-65-G cylindrical reference chamber

    • PPC-40 parallel plate chamber

    • Dose-1 electrometer

    • WP1D motorised waterphantom

  • Machine QA - SNC

    • Switching to IC-profiler or Profiler 2 (still to be decided)

    • Daily QA3 (wireless)

  • Patient QA

    • Matrixx

    • Invidos

  • Brachy QA

    • Unidos E and Sourcecheck (PBT)

    • Nucletron/Standard Imaging and PTW well chamber (HDR)


3ds how did we decide
3DS – How did we decide ?

  • Motivation :

    • WP700 system dates from 1989 and was in need for replacement

    • “New” project : commission Sli 18 for IMRT, we wanted this done without doubts about the measurement data quality

    • Increase time efficiency of water tank measurements

    • Reduce threshold to use of water tank

  • Obtained budget approval 04/2010


3ds how did we decide1
3DS – How did we decide ?

  • Requirements specifications (highlights):

    • Must

      • qualitatively perform as well or better than the old system (of course)

      • work with current detectors

      • handle current data

      • export to Pinnacle

      • TMR/TPR capable

      • Before purchase, we must work with the system to get the look and feel

    • Should

      • more user friendly

      • easier/faster to setup


3ds how did we decide2
3DS – How did we decide ?

  • On site visits at nearby centers May-June 2010

    • PTW MP3-M / Mephysto MC2

    • IBA Blue Phantom / OmniPro Accept v7

       both very qualitative and well established systems

      • IBA blue phantom and OmniPro Accept v7 seemed logical successor to our current system

  • No clinical 3DS system available in Europe at that time

  • => Visit to SNC factory


3ds how did we decide3
3DS – How did we decide ?

  • Visit SNC factory

    • First view on a functional prototype

    • Opportunity to talk to several people involved in the development of hardware and software

  • Enthousiastic team determined to deliver a innovative and qualitative product, eager to take input from (potential) users

  • Good overview of hardware, software

  • But system released early 2011, which was later than we hoped for


3ds how did we decide4
3DS – How did we decide ?

  • Competitive offers from all parties

  • Open communication with all distributors

  • Detailed comparison of all specs

  • Choice between solid well established system and young innovative system

  • Very much attracted by the novelties of the 3DS system

    • Auto setup : objective, time saving (?),

    • One-cable connection : fast, less fragile

    • Measurement database instead of files

    • Layered processing with rollback options

    • Consistent detector orientation (certainly has a positive effect but not thoroughly evaluated at that time)


3ds how did we decide5
3DS – How did we decide ?

  • But no reference and no opportunity to test at that time

    => Test site agreement

    • Gain experience with new system before it is released

    • Opportunity to provide input for new features (wish list !)

    • Possibly start measurements with test system if all works earlier than planned (optimism is good)



3ds the system1
3DS – the system

  • Main hardware differences :

    • Cylindrical geometry

      • movement in (r, theta, z) instead of (x, y, z)

      • Look less bulky

      • less water needed, less weight

      • scan range is the same for all scans ( i.e. not larger for diagonals) but is large (standard 50 cm)

      • larger scan range possible with special detector holder


Mechanical testing
Mechanical Testing

  • Relative positioning accuracy using laser pointer and chart paper

    • Ring drive

    • Vertical drive

    • Diameter drive

  • Done using controls box – without auto setup measurements (dry tank)

  • Leveling accuracy : ≤ 0.1° (accuracy of our digital level)

  • Plumb line of vertical drive using laser level (construction)


3ds s etup
3DS – Setup

  • Platform setup procedure:

    • Connect power and PDI

    • Calibrate motors platform and tank

    • Put tank approximately right

    • Fill tank and adjust height to correct SSD

    • Leave bunker and run auto setup procedure

      • Tank Leveling

      • Ring center determination

      • Tank center determination and tank adjustment

      • Ring angle offset determination

      • Hysteresis measurement



3ds auto setup calibrate platform
3DS – Auto setup – calibrate platform

  • Platform leveling and x- y- motors need to be calibrated before they can be used

  • Best done before aligning the system with the crosswire


3ds auto setup calibrate platform1
3DS – Auto setup – calibrate platform

  • Tank ring drive, diameter drive and vertical drive home positions are determined



3ds auto setup ring center
3DS – Auto setup – ring center

  • Diameter drive is mounted eccentrically to allow for the detector to be in the center


3ds auto setup ring center1
3DS – Auto setup – Ring center

  • To keep the detector in the mechanical center of the tank, it must be positioned correctly

  • In the direction orthogonal to the diameter drive -> specific distance when mounting the detector

  • In the direction along the diameter drive -> done by the system


3ds auto setup ring center2
3DS – Auto setup – Ring center

  • If the ring center would not be determined correctly, the detector would rotate on a circle around the mechanical center


3ds auto setup2
3DS – Auto setup

  • Tank adjust

    • The isocenter/beam center is determined from

      • Inline and crossline scan at collimator 0°

      • Inline and crossline scan at collimator 180°

    • The tank position is shifted to match the beam center

  • Angle offset

    • The angle of the tank is aligned with the collimator


3ds auto setup checks
3DS – Auto setup Checks

  • Check after auto setup during test period:

    • Visually check position of detector vs crosswire

    • Take scans at cardinal angles

    • Check correct position of beam edges

  • => Part of factory testing



3ds scan database
3DS – Scan database

  • Scans are grouped in projects – can be added to multiple projects

  • DB can be searched by building logical expressions of various scan parameters

  • Scan lists can filtered

  • Scans lists can be grouped










Results large scan range
Results – Large scan range

  • The standard scan range of 50 cm can be extended using the radial offset detector holder

  • 40 cm x 40 cm, d=30cm, 5 cm extra => 62cm scan


Results large scan range1
Results – Large scan range

  • Radial offset detector offsets the detector from the center of the carriage, brings it closer to the tank wall

  • Diameters driver rotates by 180° when detector is in the center


Results consistent detector orientation
Results – Consistent detector orientation

  • The cylindrical design ensures a consistent orientation of the detector : the motion always occurs transverse to the axis of the detector


Results consistent detector orientation1
Results – Consistent detector orientation

  • Intuitively important for

    • extended detectors

    • detectors with different dimensions along their respective axis

  • Tested with 3 types of detectors

    • elongated IC

    • “spherical” IC (CC13)

    • diode

  • Compared scans with axis

    • transverse to motion

    • along the direction








Results evaluation of scan parameters
Results – Evaluation of scan parameters

  • Set of scans for various field sizes and various scan settings – CC13


Results evaluation of scan parameters1
Results – Evaluation of scan parameters

  • Set of scans for various field sizes and various scan settings – Edge (diode)


Results detector choice small fields
Results – Detector choice – small fields

  • Set of scans for various detectors and optimal scan settings

  • “Sharp” vs noisy


Results detector choice large fields
Results – Detector choice – large fields

  • Set of scans for various detectors and optimal scan settings

  • “Sharp” vs noisy


Results scans with offset
Results – Scans with offset

  • Achieved by either

    • Software controlled shift of platform (offsets ~ 1cm)

    • By combination of radial and angular movement (larger offsets)


Results scans with offset1
Results – Scans with offset

  • Check off-axis shift

  • Collimator 45°

  • Scan with no offset /

  • Scan with 1 cm offset


Results scans with offset2
Results – Scans with offset

  • Check detector position ?




Summary of my findings
Summary of my findings

  • 3DS is a nice innovative system to work with : no more dreading to use it

    • Less bulky, less heavy, practical design

    • Auto setup : objective, fast(er)

    • One-cable connect

    • Database of measurement : very helpful during comissioning

    • Layered processing

      => Faster, more frequent use

  • Still being optimised and developped further based on user feedback => real strength of SNC


Acknowledgements
Acknowledgements

  • My colleague physicists, for all extra work during evenings and weekends:

    • Natalie Bal

    • Charlotte Bauwens

  • Our department head dr. Ph. Spaas

Thank you !