Dose to the Dysphagia/Aspiration-Related Structures (DARS) is critical to ensure proper swallowing functions to the patients after IMRT to the head and neck region

1. Delineation of Dysphagia/Aspiration-
Related Structures (DARS)
Dr Rajesh Balakrishnan
MD, DNB (Radiotherapy)
1

2. References for the Talk
• Radiotherapy and Oncology 93 (2009) 545–552
• Radiotherapy and Oncology 110 (2014) 390-397
2

3. Prerequisites
• Good Planning CT
– Good Immobilistaion setup
– With Contrast imaging
– 3mm Slice thickness or smaller
• Suggested the center (HU) and width (HU) values
(window settings) used to delineate the OARs
– Brain: C35, W100
– Bone: C450, W1,600
– H&N: C35, W350
– Parotid: C 840 , W 370
3

4. • Temporal Lobes
• Right Eye and Lens
• Left eye and lens
• Right Optic nerve
• Left Optic nerve
• Optic chiasm
• Pituitary
• Cochlea
• Brainstem
4
Organs at Risk (1)

5. • Spine
• Parotid Glands
• Sub Mandibular Gland
• Pharyngeal Constrictors
• Trachea
• Brachial Plexus
5
Organs at Risk (2)

6. OPTIC APPARATUS
6

7. Optic/Brain – Organs at Risk
• Temporal Lobes
• Right Eye and Lens
• Left eye and lens
• Right Optic nerve
• Left Optic nerve
• Optic chiasm
• Pituitary
• Cochlea
• Brainstem
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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397

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Radiotherapy and Oncology 110 (2014) 390–397
Odontoid
Process

23. SALIVARY GLANDS
23

24. Parotid Gland
Boundary Explanation
Cranial External auditory canal, mastoid process
Caudal Post. part submandibular space
Anterior
Masseter m, post. border mandibular bone, medial
and lateral pterygoid m.
Posterior
Ant. belly sternocleidomastoid m, lat. side post.
belly of the digastric m. (posterior-medial)
Lateral Subcutaneous fat, platysma
Medial
Post. belly of the digastric m, styloid process,
parapharyngeal space 24

25. Submandibular Gland
Boundary Explanation
Cranial Medial pterygoid m, mylohyoid m.
Caudal Fatty tissue
Anterior Lat. surface mylohyoid m, hyoglossus m.
Posterior Parapharyngeal space, sternocleidomastoid m.
Lateral
Med. surface medial pterygoid m, med. surface
mandibular bone, platysma
Medial
Lat. surface mylohyoid m, hyoglossus m, superior
and middle pharyngeal constrictor m, anterior belly
of the digastric m. 25

26. Sublingual Gland
Boundary Explanation
Cranial
(Mucous membrane covering the floor of the
mouth), crossing lingual septum , intrinsic tongue
muscles
Caudal Ant. part mylohyoid m, geniohyoid m.
Anterior Ant. part surface mandibular bone, mylohyoid m.
Posterior Hyoglossus m.
Lateral
Ant. part med. surface mandibular bone, mylohyoid
m.
Medial Genioglossus m. 26

27. Salivary Glands - Delineation
27
5 Anterior belly digastric m.
6 Geniohyoid m.
10 Sternocleidomastoid m.
11 Platysma
•
•
•
•
• Sub Lingual Glands – Dark Blue

28. Salivary Glands - Delineation
28
5 Anterior belly digastric m.
6 Geniohyoid m.
9 Pharyngeal constrictor m.
10 Sternocleidomastoid m.
11 Platysma
•
•
•
•
• Sub Lingual Glands – Dark Blue

29. Salivary Glands - Delineation
29
1 Genioglossus m.
2 Mylohyoid m.
3 Hyoglossus m.
10 Sternocleidomastoid m.
11 Platysma
15 Mandibular bone
•
•
•
•
• Sub Lingual Glands – Dark Blue

30. Salivary Glands - Delineation
30
1 Genioglossus m.
2 Mylohyoid m.
3 Hyoglossus m.
9 Pharyngeal constrictor m.
10 Sternocleidomastoid m.
15 Mandibular bone
•
•
•
•
• Sub Lingual Glands – Dark Blue

31. Salivary Glands - Delineation
31
1 Genioglossus m.
2 Mylohyoid m.
3 Hyoglossus m.
4 Posterior belly digastric m.
7 Medial pterygoid m.
10 Sternocleidomastoid m.
12 Masseter m.
13 Parapharyngeal space
•
•
•
•
• Sub Lingual Glands – Dark Blue

32. Salivary Glands - Delineation
32
1 Genioglossus m.
2 Mylohyoid m.
4 Posterior belly digastric m.
7 Medial pterygoid m.
10 Sternocleidomastoid m.
12 Masseter m.
15 Mandibular bone
•
•
•
•
• Sub Lingual Glands – Dark Blue

33. Salivary Glands - Delineation
33
4 Posterior belly digastric m.
7 Medial pterygoid m.
10 Sternocleidomastoid m.
12 Masseter m.
•
•
•
•
• Sub Lingual Glands – Dark Blue

34. Salivary Glands - Delineation
34
4 Posterior belly digastric m.
7 Medial pterygoid m.
8 Lateral pterygoid m.
10 Sternocleidomastoid m.
12 Masseter m.
13 Parapharyngeal space
14 Styloid process
15 Mandibular bone
•
•
•
•
• Sub Lingual Glands – Dark Blue

35. Parotid – Axial and Coronal
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36. Submandibular – Sagittal and Coronal
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37. SubLingual – Sagittal and Coronal
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38. SOFT PALATE
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39. Soft Palate
Boundary Explanation
Cranial
Hard palate, nasopharyngeal mucosal space/air
lumen
Caudal
Tongue base, palatine tonsils, oropharyngeal
mucosal space/air lumen
Anterior
Hard palate, tongue/tongue base, air present in
oral cavity or pharyngeal lumen
Posterior
Superior pharyngeal constrictor m, pharyngeal
mucosal space/air lumen
Lateral
Pterygoid process, medial pterygoid plate, superior
pharyngeal constrictor m, medial pterygoid m,
parapharyngeal space, palatine tonsil, pharyngeal
lumen
39

40. SOFT PALATE – Sagittal and Axial
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41. SOFT PALATE
41
1 Tongue
2 Medial pterygoid m.
3 Superior pharyngeal constrictor m.
4 Uvula
5 Hard palate
6 Medial pterygoid plate
7 Pharyngeal lumen
8 Parapharyngeal space
9 Pterygoid process
10 Level of the palatine tonsil.

42. SOFT PALATE
42
1 Tongue
2 Medial pterygoid m.
3 Superior pharyngeal constrictor m.
4 Uvula
5 Hard palate
6 Medial pterygoid plate
7 Pharyngeal lumen
8 Parapharyngeal space
9 Pterygoid process
10 Level of the palatine tonsil.

43. SOFT PALATE
43
1 Tongue
2 Medial pterygoid m.
3 Superior pharyngeal constrictor m.
4 Uvula
5 Hard palate
6 Medial pterygoid plate
7 Pharyngeal lumen
8 Parapharyngeal space
9 Pterygoid process
10 Level of the palatine tonsil.

44. SOFT PALATE
44
1 Tongue
2 Medial pterygoid m.
3 Superior pharyngeal constrictor m.
4 Uvula
5 Hard palate
6 Medial pterygoid plate
7 Pharyngeal lumen
8 Parapharyngeal space
9 Pterygoid process
10 Level of the palatine tonsil.

45. SOFT PALATE
45
1 Tongue
2 Medial pterygoid m.
3 Superior pharyngeal constrictor m.
4 Uvula
5 Hard palate
6 Medial pterygoid plate
7 Pharyngeal lumen
8 Parapharyngeal space
9 Pterygoid process
10 Level of the palatine tonsil.

46. SOFT PALATE
46
1 Tongue
2 Medial pterygoid m.
3 Superior pharyngeal constrictor m.
4 Uvula
5 Hard palate
6 Medial pterygoid plate
7 Pharyngeal lumen
8 Parapharyngeal space
9 Pterygoid process
10 Level of the palatine tonsil.

47. LIPS AND BUCCAL MUCOSA
47

48. Inner Surface Upper Lips
Boundary Explanation
Cranial
Hard palate (lateral), anterior nasal spine (at the
midline)
Caudal Lower edge upper lip
Anterior Orbicularis oris m, subcutaneous tissue/fatty skin
Posterior Teeth, maxillary bone, hard palate, tongue
Lateral
Depressor anguli oris m, buccinator m, levator anguli
oris m./risorius m.
48

49. Inner Surface Lower Lips
Boundary Explanation
Cranial Upper edge lower lip
Caudal
Lower edge teeth sockets, cranial edge mandibular
body
Anterior Orbicularis oris m, subcutaneous tissue/fatty skin
Posterior Mandibular body, teeth, tongue, air (if present)
Lateral Depressor anguli oris m, buccinator m.
49

50. Inner Surface Cheeks
Boundary Explanation
Cranial
Transition between maxillary sinus and alveolar
process maxilla
Caudal Alveolar process mandible
Anterior Orbicularis oris m.
Posterior Post. edge mandibular body, post. edge maxilla
Lateral Buccinator muscle, fatty tissue
Medial Mandibular body, teeth, tongue
50

51. 51

52. 52
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

53. 53
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

54. 54
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

55. 55
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

56. 56

57. 57
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

58. 58
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

59. 59
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

60. 60
1 Orbicularis oris
2 Tongue
3 Fatty tissue
4 Hard palate
5 Mandibular body
6 Maxillary bone
7 Anterior nasal spine
8 Buccinator m
9 Levator anguli oris/risorius
m
10 Alveolar process maxilla
11 Maxillary sinus
12 Depressor anguli oris m

61. PHARYNGEAL CONSTRICTORS
61

62. Superior Constrictor Muscle
Boundary Explanation
Cranial Occipital condyle
Caudal Superior Edge of Hyoid Bone
Anterior Anterior edge of pterygoid muscle
Posterior Longus Capitis muscle
Lateral Palatine Tonsil or Parapharyngeal space
Medial Pharynx
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67. Middle Constrictor Muscle
Boundary Explanation
Cranial 0.5 cm Above Hyoid bone
Caudal Inferior Edge of Hyoid Bone
Anterior Oropharynx, Lateral edge of Hyoid bone
Posterior Longus Capitis muscle
Lateral Palatine Tonsil or Parapharyngeal space
Medial Pharynx
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71. Inferior Constrictor Muscle
Boundary Explanation
Cranial Inferior edge of Hyoid bone
Caudal Esophagus
Anterior Arytenoid, First Tracheal ring
Posterior Longus Capitis muscle, Anterior Vertebral body
Lateral Parapharyngeal space, Lateral edge of Thyroid
Medial Pharynx
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Radiotherapy and Oncology 110 (2014) 390–397

78. Dose Constraints
Constrictors Mean Dose < 50 Gy QUANTEC
Lips Mean Dose <20 Gy
For parotid tumor: Max < 30Gy
For SM tumor : Max < 45 Gy
RTOG 1008
Oral Cavity (Non OC tumor) Mean < 30 Gy ;
No hot spots > 60 Gy
RTOG 0920
Oral Cavity (OC tumor) Mean < 50 Gy ;
V55 < 1 %
Max dose -65 Gy
RTOG 0920
TMJ / Mandible Max 70 Gy RTOG 0615
Larynx Mean < 44 Gy ;
V50 < 33 %
Max dose - 63 -66Gy
QUANTEC
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79. Dose Constraints
Parotid Glands Mean < 25 Gy (Both glands)
Mean < 20 Gy (Single gland)
QUANTEC
Submandibular Glands Mean < 35 Gy QUANTEC
Thyroid V26 < 20 % JHH guidelines
Cochlea Ipsilateral Max <50Gy
Mean < 45 Gy
RTOG 1016
QUANTEC
Eyes Max <30 Gy RTOG 1008
Lens Max : < 2.5 Gy RTOG 1008
Optic nerve/ Chiasm Max < 30 Gy RTOG 1008
Brainstem Entire Brainstem – < 54 Gy
V59Gy < 1-10cc
QUANTEC
Spinal cord Max 50 Gy QUANTEC
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80. Conclusion
• Correct Contouring of OARs is as important to
contouring of Target.
• Whenever in doubt please refer to atlases
available online.
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