Simulation is the most critical step of radiation planning for an optimal outcome

1. Simulation Protocol: GYN
Dr Ajeet Kumar Gandhi
MD (AIIMS), DNB, UICCF (MSKCC,USA)
Assistant professor, Radiation oncology
Dr RMLIMS, Lucknow

2. Patient preparation, Immobilization,
Imaging, Simulation etc.
Target /OAR delineation
DRR, Beam placement, Plan generation, Evaluation
Treatment verification, Treatment delivery

3. Prior to simulation
 Clinical examination and documentation
 Review imaging, staging
 Anatomical variations/need of nodal boost/para-aortic
irradiation
 Finalize intended treatment plan
 Technique of RT (Conventional/conformal)
 Counselling about treatment course, expected
outcome, acute and late side effects

4. Prior to simulation
 Written informed consent
 Part preparation (perineum)
 Bowel preparation
 Bisacodyl tablets
 Treatment of constipation
 Instructions to maintain bowel clearance throughout
treatment

5. Positioning of patient
 Should be reproducible,
comfortable
 Supine position
 Most commonly used in
GYN EBRT
 Hands on chest or above
head
 Legs straight and heel
together
 Prone position
 May be used with a belly
board
 In post-operative cases of
cervix and Endometrium

7. Positioning of patient
 Frog Leg position
 Used in vulvar and vaginal cancer
 Intended treatment volume: Inguinal nodes

8. Immobilization

9. Immobilization
 Avoid in obese patients
 Use a six-clamp device
 Tattoo upper and lower
borders for reproducibility
 May cut the orifit and put
skin tattoos
 Avoid in frog leg position

10. Immobilization

11. Organ filling protocols: Bladder
 Bladder:
 Empty bladder
 Full bladder (varying protocols 500-1000 ml)
 Comfortable filling (450-500 ml before 1 hour)

12. ITV Concept
 Scan empty bladder with Intravenous contrast
 Administer oral contrast
 Scan full bladder
 Both in treatment position
 Fuse both the images

13. Organ filling protocols: Rectum
 Maintain rectal clearance throughout
 Advice on day of simulation and throughout
 Don’t hesitate to repeat scan if rectum is too much loaded

14. Markers and wires
 Put internal vaginal
marker (lower extent of
disease or vault)
 Temporary manual
 Titanium clips
 Barium soaked gauze
 Marker at the perineum
 Wire palpable nodes,
post-op scars

15. Contrast materials
 Intravenous contrast (Inj.
Omnipaque/Iomerol @
2cc/kg) preferably via an
automatic timed contrast
injector), unless medically
contraindicated or patients
had history of contrast
allergy.

16. Contrast materials
 An oral contrast may be
used to opacify small
bowel (optional)
 Per-rectal barium for
localizing the rectum
 Per-vaginal barium

17. CT Simulation
 Field of view: Large (80-85 cm)
 Pelvic RT: Upper border of T12 Vertebrae to 5cm below ischial
tuberosity
 Slice thickness: (2.5-5 mm) ≤ 5 mm
 No interslice gap
 Table increments: 3mm
 Flat table couch

18. PET-CT Simulation:
Investigational Active bone marrow
delineation: Bone
marrow sparing IMRT
 Nodal boost: SIB-IMRT

19. Adaptive RT: Investigational
 Uncertainties
Dosimetric
Radiobiological
Contouring

20. Take home message!!
 Simulation is one of the most important step of
radiation therapy planning
 Requires pre-planning, counselling
 Comfortable and reproducible immobilization
and positioning
 Take care of organ filling (inter and intra-
fraction)
 PET-CT simulation and adaptive RT are
investigational

21. Thank you!!