1. Conformal radiotherapy and IMRT
in Head and Neck Tumors
The “academic”
view point

2. Target volumes in Radiation Oncology:
ICRU definition
• Gross Tumor Volume: GTV
• Clinical Target Volume: CTV
• Planning Target Volume: PTV
ICRU report 62, 1999

3. Immobilization of
Head & Neck patients
l 15 head & neck tumors
l 15 brain tumors
l 3 different masks (3, 4 & 5 FP)
l 3 fictitious isocenters

4. Immobilization of Head & Neck patients
l 915 portals images acquired.
l 98 % analysed.
l Total Displacement.
u SIM - EPIDi
l Systematic Displacement.
u M(SIM - EPIDi)
l Random Displacement.
u (SIM - EPIDi) - [ M(SIM -
EPIDi)]
l Intraobserver variation:
0.7 mm (1 Sd).

5. 1.0
Cumulative incidence
0.9
0.8 Head
0.7
0.6
(3-5 FP) Total 3-D
0.5
0.4
0.3 deviations
0.2
0.1
0.0
0 1 2 3 4 5 6 7 8 9 10
Deviation from the isocenter (mm)
1
1.0 0.9
Cumulative incidence
Shoulder
Cumulative incidence
0.9 0.8
0.8 Neck
0.7
0.7 (4 & 5 FP)
0.6
(3-5 FP) 0.6
0.5
0.5
0.4 0.4
0.3 0.3
0.2 0.2
0.1 0.1
0.0 0
0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Deviation from the isocenter (mm) Deviation of the isocenter (mm)

6. Characteristics of current
imaging modalities
CT MRI PET fMRI
Image characteristics
skin contour + ± ± -
soft-tissue contrast ± + - -
bone contrast + ± - -
air contrast + ± ± -
metallic artefacts + ± - ±
movement artefacts - + ± +
Machine characteristics
large “tunnel” size + - - -
distortion - + ± +
electron density + - ± -
multiplannar imaging - + ± +

7. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Image acquisition
• Dual detector spiral CT
• 2.7 mm collimation, pitch 0.7,
reconstruction of 2 - 2.5 mm
• Display matrix of 512 x 512
pixels
• Contrast enhancement
(interstitial and blood vessel
contrast)

8. Conformal radiotherapy:
reference coordinates

9. Conformal radiotherapy:
3D reconstruction

10. Conformal radiotherapy:
3D reconstruction

11. Conformal radiotherapy:
image display

12. The present … which CTV for the neck ?
Cervical lymph node groups
(MSKCC classification)
Adopted by the
Academy’s Committee for
Head & Neck Surgery and
Oncology
Robbins et al, 1991

13. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Definition of the extend of the CTV in the neck
State of the art
• Predictive pattern of lymph node involvement in
HNSCC
• Selective neck treatment (irradiation or dissection)
for selected N stage

14. The present …CT-based delineation of
lymph node levels in the neck
Ia
Ib VI
III
RP V
II
Grégoire et al., 2000

15. Conformal radiotherapy:
volume delineation

16. Conformal radiotherapy:
volume delineation

17. Conformal radiotherapy:
Beam selection

18. B
E
V

19. Conformal radiotherapy:
Dose distribution

20. Conformal radiotherapy:
Dose distribution

21. Conformal radiotherapy:
Dose volume histogram

22. Conformal radiotherapy:
Dose volume histogram

23. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Mr H. D. (77 years): T3-N0-M0 base of tongue (ICD0-10: C01)

24. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Mr H. D. (77 years): T3-N0-M0 base of tongue (ICD0-10: C01)
Target volumes
• T: CTV1: GTV + 1.5 cm margin
CTV2: GTV + 0.5 cm margin
PTV1&2 : CTV + 4 mm
• N:CTV: R & L LII - IV
PTV: CTV + 4 mm
Dose prescription
• T: PTV1: 50 Gy, 25x2 Gy
PTV2: 70 Gy, 35x2 Gy
• N:PTV: 50 Gy, 25x 2Gy

25. Conformal radiotherapy and IMRT
in Head and Neck Tumors
“Antique”
(7 fields)
Rx 6 MV Rx 6 MV
40 Gy 30 Gy
Elect 8 MeV Rx 6 MV
10 Gy 50 Gy

26. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Dose (Gy) at various organs at risk
Antique Middle-age Art nouveau
PTV 55 Gy
Dmean 63.2 60.1 59.2
Dmax 79,1 76.6 74.6
Dmin 10.0 39.1 44.4
SD 10.2 9.5 8.1
PTV 70 Gy
Dmean 72.4 71.7 70.6
Dmax 76.9 76.5 74.6
Dmin 67.4 65.2 67.0
SD 1.8 2.1 1.5
L parotid
Dmedian 68.7 52.1 50.7
Dmax 72.8 72.5 71.8
Dmin 46.4 8.4 5.4
SD 7.6 12.2 15.5
R parotid
Dmedian 69.6 65.7 40.6
Dmax 72.9 72.6 55.9
Dmin 62.1 4.4 3.6
SD 1.7 24.9 16.7

27. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Dose (Gy) at various organs at risk
Antique Middle-age Art nouveau
Spinal cord
Dmean 22.8 19.6 22.7
Dmax 43.0 41.9 47.6
Dmin 5.5 3.3 2,7
SD 16.0 16.1 18.0
Mandibula
Dmedian 71.5 68.9 60.5
Dmax 76.8 74.5 72.2
Dmin 51.1 4.8 3.7
SD 2.2 22.0 17.4
Internal contour
Dmedian 41.6 13.6 19.3
Dmax 79.2 76.6 74.6
Dmin 2.0 1.2 1.1
SD 21.5 23.4 22.2

28. Conformal radiotherapy and IMRT
in Head and Neck Tumors
“Middle Age”
(9 fields)
Rx 6 MV Rx 6 MV
40 Gy 10 Gy
Elect 8 MeV Rx 6 MV Rx 6 MV
10 Gy 20 Gy 50 Gy

29. Conformal radiotherapy and IMRT
in Head and Neck Tumors
“Middle Age”
(9 fields)
Rx 6 MV Rx 6 MV
40 Gy 10 Gy
Elect 8 MeV Rx 6 MV Rx 6 MV
10 Gy 20 Gy 50 Gy

30. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Dose (Gy) at various organs at risk
Antique Middle-age Art nouveau
PTV 55 Gy
Dmean 63.2 60.1 59.2
Dmax 79,1 76.6 74.6
Dmin 10.0 39.1 44.4
SD 10.2 9.5 8.1
PTV 70 Gy
Dmean 72.4 71.7 70.6
Dmax 76.9 76.5 74.6
Dmin 67.4 65.2 67.0
SD 1.8 2.1 1.5
L parotid
Dmedian 68.7 52.1 50.7
Dmax 72.8 72.5 71.8
Dmin 46.4 8.4 5.4
SD 7.6 12.2 15.5
R parotid
Dmedian 69.6 65.7 40.6
Dmax 72.9 72.6 55.9
Dmin 62.1 4.4 3.6
SD 1.7 24.9 16.7

31. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Dose (Gy) at various organs at risk
Antique Middle-age Art nouveau
Spinal cord
Dmean 22.8 19.6 22.7
Dmax 43.0 41.9 47.6
Dmin 5.5 3.3 2,7
SD 16.0 16.1 18.0
Mandibula
Dmedian 71.5 68.9 60.5
Dmax 76.8 74.5 72.2
Dmin 51.1 4.8 3.7
SD 2.2 22.0 17.4
Internal contour
Dmedian 41.6 13.6 19.3
Dmax 79.2 76.6 74.6
Dmin 2.0 1.2 1.1
SD 21.5 23.4 22.2

32. Conformal radiotherapy and IMRT
in Head and Neck Tumors
“Art nouveau” (10 fields, 12 segments )
SRAO SLAO Post. Seg. 1 Post. Seg. 2
Rx 6 MV 50 Gy
RPO LPO Ant. …

33. Conformal radiotherapy and IMRT
in Head and Neck Tumors
“Art nouveau” (11 fields, 12 segments )
Ant. RAO LPO
Rx 6 MV 20 Gy
LAO1 LAO2

34. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Dose (Gy) at various organs at risk
Antique Middle-age Art nouveau
PTV 55 Gy
Dmean 63.2 60.1 59.2
Dmax 79,1 76.6 74.6
Dmin 10.0 39.1 44.4
SD 10.2 9.5 8.1
PTV 70 Gy
Dmean 72.4 71.7 70.6
Dmax 76.9 76.5 74.6
Dmin 67.4 65.2 67.0
SD 1.8 2.1 1.5
L parotid
Dmedian 68.7 52.1 50.7
Dmax 72.8 72.5 71.8
Dmin 46.4 8.4 5.4
SD 7.6 12.2 15.5
R parotid
Dmedian 69.6 65.7 40.6
Dmax 72.9 72.6 55.9
Dmin 62.1 4.4 3.6
SD 1.7 24.9 16.7

35. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Dose (Gy) at various organs at risk
Antique Middle-age Art nouveau
Spinal cord
Dmean 22.8 19.6 22.7
Dmax 43.0 41.9 47.6
Dmin 5.5 3.3 2,7
SD 16.0 16.1 18.0
Mandibula
Dmedian 71.5 68.9 60.5
Dmax 76.8 74.5 72.2
Dmin 51.1 4.8 3.7
SD 2.2 22.0 17.4
Internal contour
Dmedian 41.6 13.6 19.3
Dmax 79.2 76.6 74.6
Dmin 2.0 1.2 1.1
SD 21.5 23.4 22.2

36. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Forward planning IMRT
• « human optimization »
Inverse planning IMRT
• Dose-volume constraints & weights for PTV and OARs
• optimization algorithms
• Penalty function

37. Inverse planning IMRT for
Head and Neck Tumors
Cummulative % of MUs
l Spare cord Segment #
l Spare left parotid 1 6.
l 15 segments
l 10 levels
Courtesy of C. Field

38. Inverse planning IMRT for
Head and Neck Tumors
PTV
Spared parotid gland
Courtesy of C. Field

39. Parotid gland function
lemon
juice
370 MBq 99mTc-pertechnetate

40. Parotid gland function
Objective assessment
100
90 R= 0,77
Maximum secretion (%)
80
70
60
50
40
30
20
Bilateral irradiation
10 Unilateral irradiation
0
0 10 20 30 40 50 60 70
Mean parotid dose (Gy)

41. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Duration of treatment planning procedure
2D planning Forward planning Inverse planning
(St-Luc) (Edmonton Cancer center)
Volume delineation 0 - 0.25h 2 - 3h 1 - 1.5h
Planning 0.25h 2 - 8h 1 - 2h
Individualized QC 0h 0.25h 1h
Treatment (per session) 10 - 15 min 20 - 25 min 15 min

42. Conformal radiotherapy and IMRT
in Head and Neck Tumors
Definition of the extend of the CTV in the neck
State of the art
• Predictive pattern of lymph node involvement in
HNSCC
• Selective neck treatment (irradiation or dissection)
for selected N stage