Virtual Simulation in the Radiooncology Department of B-A-Z County Hospital Miskolc

Imre GesztiCertificated 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

Digitaly based imaging

Conventional RT Simulator

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 SimulationOlder 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 SimulationNewer 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

Starting positionCT topogramRegion selction

CT scanning

Ref. Point managementRef. point marking

Image transfer Image import

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 Portal Image (6MV X-ray EPID)

Fused Images

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