Radioiodine Therapy

Question 1

What are two ways that radioiodine therapy can be used after thyroidectomy?

Answer 1

low doses- demonstrate residual thyroid tissue or metastatic disease

high doses- ablation of remnant thyroid tissue to facilitate detection of later disease recurrence by imaging and Tg assay

-adjuvant therapy with targeting occult metastatic disease

Question 2

Indications for RAI Therapy

Answer 2

for tumours > 4cm:
microscopic extrathyroidal extension
central or lateral compartment mets

for tumours 1-4 cm:

• adverse histologic subtype (tall cell/vascular invasion)
• most stage II disease (45 years old and less- everyone, 46 and up- most people)

Question 3

Contraindications to RAI

Answer 3

Low risk DTCs <1 cm without direct extrathyroidal extension or metastases