Virtual Simulation in the
Radiooncology Department of
B-A-Z County Hospital Miskolc
Imre Geszti
Certificated Clinical Radiophysicist
Miskolc
Hungary
Short History
• Early ’60s Superficial Skin Therapy (Chaoul, Dermopan)
• 1974 Founded of the Department of Radiooncology, Teletherapy (Cs,
Co therapy)
• 1975 Brachytherapy (GUA)
• 1977 National Therapy Planning Networking System
– Transverse sectioning device
• 1991 PC based therapy planning (van de Geijn)
• 1994 Theratron 780c, Gammamed 12i (Gammadot TPS for
brachytherapy)
• 2002 Siemens Primus Dual Energy, digital linac machine, Siemens
SimView NT conventional Simulator, real 3D CT based TPS (CMS
XiO), connection to the hospital CT scanner via the network system
– 2005-2007 Intracranial Stereotaxia (Brainlab) (ended by „politics”)
• 2007 Siemens Oncor Impression linac, Siemens Somatom sensation
Open CT Simulator (LAP Dorado laser system, Coherence Dosimetris
Workstation)
• 2008 2nd Oncor linac
• 2014 ? IMRT, IGRT, (VMAT or RapidArc?), SRS, new Brachytarapy
equipment, TPS
Devices I.
• Conventional RT Simulator
– Siemens SimView NT (2002)
– Image intensifier
• DICOM Image server
• Every Images are DICOM based
Conventional RT Simulator
Digitaly based imaging
Devices II.
• CT Simulator
• Siemens SOMATOM Sensation Open (2007)
– CT with flat table top
– LAP Dorado Laser system
– Coherence Dosimetrist (Virtual Simulator Software)
workstation
Siemens Somatom Sensation Open
CT simulator, Coherence Dosimetrist ws
LAP Dorado laser system
Devices III.
• For delineation, and verification
– Coherence Oncologist
• TPS
– CMS XiO
– Permedics Odyssey
Virtual Simulation
Older methodology
• Presimulation in conventional Simulator
– Marking of the center of the region
• Processing CT Images
– In another department (not the same building)
– Sending via network (advanced version)
– Sending via CD-, DVD-ROM
• 3D Therapy Planning system
• Contouring
• Planning
• Processing of DRRs, hardcopy of isocentric plain
• Simulation after the planning
– Mark the sign of the „Isocenter”
• Verification
– Film
– EPID
Virtual Simulation
Newer methodology I.
•
•
•
•
•
•
Pre- and postplanning processing in one step
Patient positioning
AP topogram (fix tube position)
Selecting the region
CT Imeges
Possible postprocessing (changing kernels or
other processing details slice thickness etc.)
• Sending the images
Virtual Simulation
Newer methodology II.
• VSim software
– Delineating (Skin, OAR, PTV)
– Reference point managment
– Other DICOM format images registration (fusion of
images) (MRI, Diagnostic CT, PET etc.)
• Virtual beam simulation
• Room-, Beam eye view
• Virtual machine
• Without dose calculation
Workflow diagram (CT Simulator)
Patient registration
Patient positioning
Defining laser origin
Region selction
CT topogram
Starting position
CT scanning
Image transfer
Image import
Ref. point marking
Ref. Point management
Skin Contouring
Laser, table coordinates
Marking on patient skin
Other details, postprocesses
CT-CT fusion
Without contrast
With contrast
CT-MR fusion
CT
MR
CT-PET fusion
CT
PET
More spectacular fusion of PET and CT
• Easier to find
the correct
place of
tumor, and
involved
tissue volume
Creation of the virtual beams
Therapy planning preprocedure
• Plan calculation (3D TPSs)
• Parameter changing possibilities
(comformalization of MLCs, selecting adequate
beam energies, wedges etc.)
• Making hardcopies (images of slices, plan
parametres)
• DRRs (paper based, and digitaly format)
• Parametres for R&V (Lantis)
Deviations
• Random error
– From inadequate
positioning
– Changes of the patient
weight
– From device (laser,
table, light field etc.)
• Intended deviation
– Replace the reference
point for better dose
distribution
– For using different
centre of treating
volumes (whole breast
vs. tumor bed)
Verification I.
• Optivue 500 Flat panels on Oncor Impression
linacs (semiconductor based EPID)
• Coherence Therapist workstations
– Dedicated for both of the Oncor machines
– Possibilities of Portal Imaging application
– Fusion of digital format Portal or Verificational Image
with DRRs
– 3 directions (lat., long., vert.) eliminate deviations in 1
mm resolution
Verification II.
DRR with contours
Fused Images
Portal Image (6MV X-ray EPID)
Verification III.
Bony structure based
Bony
structure
based
registration
Verification IV.
Inplanted marker based
Relative to
inplanted
markers
Prostate case
More precise if
we can use
some „Gold
markers”
Differencies
relative to DRR it
needs to adjust
Important considerations
• Accuracy of patient treatment
– Precise lasers,
– Table top (roll, tilt)
• Rotating
• Deflection
– Patient fixation
• Verification on Linacs
– No soft tissue sensitivity (relative to bony structure)
– No tissue moving or respiration tracking
• So we believe we’ll have IGRT the near future
• Human factor. What do they contour, where is
the real tumor or tumor bed?
Thank you for your attention
Happy birthday for Prof. Matula