1. Radio Iodine Therapy In Cancer Thyroid
Prof. Dr. Hosna Moustafa
Professor of NM depart.
Cairo University, Egypt

2. Diagnosis
Tc99m- thyroid scan may show autonomous hot nodule which is rarely malignant, or cold nodule which may be malignant in 10 – 15% .
Fine needle aspiration biopsy is needed for final diagnosis guided by ultrasound .

3. Picture for solitary cold nodule

4. Treatment lines
Surgery.
Radio-iodine.
Hormonal

5. Technical consideration of whole body 131I scanning
Patient preparation:
Physician to instruct patient to be in low iodine diet.
Thyroid medication should be stopped for 4 weeks.
Radiopharmaceutical:
Dose 1 – 2mCi 131I given to fasting patient with no further eating for 2 hours.
Equipment:
High energy parallel whole collimator, with 20% window in 364 kev of 131I.

6. Procedure
It is performed after surgery or radio iodine therapy after 6 months.
Whole body scanning at 48 or 72 hours 10cm/min.
Spot view on thyroid for 5 minutes.
SPECT/CT for neck and chest is a viable Image interpretation:
Normal uptake in salivary glands, stomach, colon and urinary bladder.
Any radiotracer accumulation in neck or metastatic sites in lung, bones or brain should be considered abnormal.

7. I-131 Whole body scans
Neck residue
+ Lung mets
Normal
Neck residue

8. Metastatic lesions to bone with SPECT CT localization

9. Metastatic lesions to lungs with SPECT CT localization

10. 131I therapy: radiopharmaceutical
iodine-131 (131I) as sodium iodide
physical half life: 8.1 d
principle γ-ray: 364 KeV
principle β-particle: max. E 0.61 MeV, average E MeV
mean range in tissue 0.8 mm (max. 2.4 mm)
Administered dose:
remnant thyroid tissue: mCi
local metastases: mCi
pulmonary metastases: 80 – 100 mCi
bone metastases: 150 – 200 mCi

11. Before ablation
After ablation

12. Metastatic lung case, with good response to therapy

13. Thank you