2. S. N. Kaale- DDR-UDSM, B.TECH,-J’burg
SA, MSc fellow SHU,-UK.
Radiotherapist
3D CRT-OVERVIEW
3. OVERVIEW
The design and delivery of radiotherapy
treatment plans based on 3-D image
data
Treatment fields individually shaped to
conform to the treatment target volumes
(TV),
Sparing critical organs or all Organs At
Risk OAR
4. Rational of Conformal
Therapy
Achievement of Dose Escalation
To improve Tumor Control
Increase overall survival
Reduction of Normal Tissue
Complications
To improve quality of life.
ALL THIS REQUIRES A HIGH LEVEL
OF ACCURACY
5. TECHNOLOGICAL INNOVATION
Invention of CT ,MRI, PET, Ultrasound
Image FUSION and better target delineation
Developments in network and data transfer
technology (DICOM )
Developments in software for Computer
Controlled MLC.
Developments in TPS, and RVS
6. 3D CRT AS A COMPLEX
PROCESS
• Disease Treated
• Technology Employed
• Information Flow
• Human Interactions
• Treatment Evaluation
7. THE PROCESS OF RADIATION
TREATMENT
.
Verification
Prescription
Simulation
Planning
Diagnosis
Delivery
Following/Evaluation
IMAGING IS CENTRAL
TO EACH STEP IN THE
PROCESS
8.
9. TYPICAL - 3D WORKFLOW
Immobilization
Simulation
Contouring
Beams placement and Dose Calculations
Plan Evaluation and Approval.
Data transfer to RVS for treatment.
Treatment Verification (part of QC)
Dose delivery and follow up.
10. Immobilization
Roles:
Maintain patient position during the course of
radiotherapy by using different immobilization
devices.
For accurate dose delivery to the target volume,
while sparing organ at risk
Reduces setup error and patient movement
during treatment.(Random and systematic error)
11. Immobilization cont…
Proper immobilization reduces risk of side
effects
Proper immobilizing reduce the time for daily
patient set up
Help to stabilize the relationship between
external skin marks and internal structures
13. SIMULATION
Image acquisition provides foundation for
treatment planning.
Usually more than one imaging modalities are
required for better delineation of target volume
Images are acquired for :
Treatment planning
Image guidance and/or treatment verification
Follow-up studies (during & after treatment)
14. Simulation cont…
CT is done with patient in the treatment
position in immobilization device .
Radio opaque mark are placed .
These mark assist in any coordinate
transformation needed as a result of 3D
planning and eventual plan
implementation.
15. Simulation cont…
A topogram is generated to insure that patient
alignment is correct & then using localizer,
area to be scanned is selected.
The FOV is selected to permit visualization of
the external contour, which is required for
accurate dose calculations.
Using site dependent protocols, images are
acquired.
The planning CT data set is transferred to a
3D-TPS or workstation via a computer
network.
18. PLAN EVALUATION
The following tools are used in the evaluation
of the planned dose distribution:
2-D display
Isodose lines
Color wash
DVHs (Dose volume histograms )
Dose distribution statistics
19. Dar es salaam city 1961 Dar es salaam city 201
THANK YOU
FOR
LISTENIN
G
20. A 61 years old male with Sino nasal tumor
who presented at Besta super specialized
polyclinic for 3D CRT.
SINONASAL TUMOR 3D CRT-CASE
PRESENTATION
21. Reuben Mringo- Bsc RTT-(MUHAS)
Radiotherapist
Immobilization and Simulation