1. The document discusses common pitfalls of 18F-FDG PET/CT in head and neck oncology such as inflammation, infection, and partial volume averaging effects. 2. It provides modifications to avoid pitfalls including using a neck collar, keeping the patient quiet and warm, massaging salivary glands, and having head and neck surgeons interpret scans. 3. Proper patient preparation before PET/CT and being aware of common pitfalls are emphasized.

1. Pitfalls & Modifications of
18F-FDG PET/CT in
Head & Neck Oncology
Dr. KEN-LIAO LIU
Otolaryngology Head & Neck Surgery
台中市 光田綜合醫院 耳鼻喉頭頸科
劉耿僚 醫師

2. Case 1: Tongue carcinoma

3. Clean Neck

5. Post OP F/U

9. Post OP 3 months

10. Case 2: R’t supra-clavicular masses

11. FNA cytology: atypia ?

14. Case 3: NPC

15. Post R/T 2 years

18. F/U: negative !

19. Case 4: Epiglottis ca.

23. Case 5: Right buccal ca.

24. Pre-op

26. Post-OP (PMMCF) & R/T

27. Post-op & R/T 3 months

29. Post-op F/U

30. Case 6: Right Retromolar ca.

31. Winter

32. Summer

33. Summer

34. Case 7-1: NPC (CT: cT1N1)

35. Post R/T 1.5 years

38. Case 7-2: R’t Glottic CA ??

41. Case 8: Thyroid papillary ca post op
< 1 cm LAP, low SUV !!
Patho: Metastatic papillary carcinoma
Partial Volume Averaging Effect !!

42. Conclusion
Common Pitfalls :
★ Inflammation & Infection
• Post-Tx effect: Post-op & R/T ORN, C/T(thymus, bone marrow)
• Granulation, Necrosis
• Salivary glands
• TB, Granulomatous disease, Abscess, Autoimmune disease
• Smokers’ mediastinal Lymphadenitis...etc.
★ Waldeyer’s ring
★ Brown fat
★ Muscle activity
★ Partial volume averaging effect ( Inadequate scanner
resolution)

43. Prerequisites before PET/CT
• Fasting – 4-6 h
• No strenuous exercise 24 h before PET
• Check blood glucose ( >200 ?)
• After FDG injection, rest in bed !
• P’t should void before scanning
• Remove any metallic objects
• Make P’t comfortable under the scanner

44. Modifications to Avoid Pitfalls
• Neck collar
• Keep quiet
• Keep warm
• Massage salivary glands
• Anti-tussives
• Benzodiazepines (Valium)
• NSAIDs , Antibiotics
• Tongue depressor/mold
• Visual interpretation rather than SUV

45. Bone invasion ?

46. Tongue depressor

47. Tongue depressor

48. Tongue depressor

49. NSAIDs
(Hypopharyngeal ca post total laryngectomy)

50. Mapping of the Tumor & Interpretation of
PET/CT by Head & Neck Surgeons Is
Absolutely Necessary !!

51. Take Home Message:
1. Proper P’t Preparation before PET/CT
2. Common Pitfalls in Your Mind
Thank You !
• Dr. KEN-LIAO LIU
• Otolaryngology
Head & Neck
Surgery , KTGH , Taichung, Taiwan
• 光田綜合醫院 耳鼻喉頭頸科
劉耿僚 醫師