1. Radionuclide Imaging of Endocrine Disorders
Bin.Liu, MD, PhD,
Department of Nuclear Medicine
West China Hospital, Sichuan University
2018/6/23 1

2. Diagnosis and Therapy with
Nuclear Medicine(NM)
Diagnosis and Therapy with
Unsealed Sources
Clinical Problem
Radiopharmaceutical Instrumentation 2

3. Outline of NM in endocrinology
Organs:
Thyroid
Parathyroid
Adrenal Gland
Nuclear Medicine:
Tracers, technical aspects
Relationship to patient diagnostic pathways and other
imaging modalities
Contribution to management and treatment 3

4. Thyroid physiology
Anatomy Histology 4

5. Thyroid physiology Iodine turnover: Uptake(trapping): NIS
Organification: T4, T3
Deposition and release 5

6. Iodine metabolism in thyroid
Increased iodine uptake: iodine deficiency,
hyperthyroidism
Decreased uptake: iodine saturated thyroid (drugs, food), hypothyroidism (both periferal and central)
TSH fT fT3 Iodine uptake
Hypothyroidism High Low Low Low
Hyperthyroidism Low High High High 6

7. Thyroid imaging When should it be performed?
How does it help diagnosis?
What alternatives are there for imaging the
thyroid?
How do the results of the nuclear medicine
scan affect treatment? 7

8. Thyroid Imaging Thyroid imaging is based on the physiologic
process of thyroid hormone production
The thyroid tissue cannot differentiate between non-radioactive and radioactive iodine 8

9. Thyroid Imaging Indications: Contraindications:
goiter (palpable, US finding > 10 mm)
hyperthyroidism (Graves disease, autonomous adenoma)
subacute thyroiditis (deQuervain)
ectopic thyroid gland, evaluation of substernal mass
neonatal hypothyroidism
preceding 131I therapy – iodine uptake
postoperative search for functioning metastases
Contraindications:
pregnancy
breastfeeding 9

10. Thyroid imaging Nowadays importance is decreasing - management of
thyroid diseases is changing:
anatomy: US
palpable or US visualized nodule: immediately FNAB
supersensitive TSH assay, fT4, fT3: uptake study is not needed
anti-TPO, TRAB – differentiate Graves disease from other types of
hyperthyroidism
but still essential:
reveal functional autonomous areas in thyroid
iodine uptake prior to radioiodine therapy (number is increasing)
whole body 131I scan after thyroidectomy for malignancy
looking for ectopic thyroid tissue
advantage: quick, cheap 10

11. Thyroid imaging-patient preparation
Only scintigraphy: no withdrawal of anti-thyroid drugs (propylthiouracil, methimazol)
Withdrawal thyroid hormones: T4 for 4 wks
T3 for 2 wks
Avoid iodine containing drugs, food (200 ug/day) for 4 wks (special: amiodarone-several months)
Important:
History (physical examination)
Thyroid US finding
Image of previous thyroid scintigraphy
Hormone levels: TSH, fT3,fT4 11

12. Thyroid scintigraphy -Radiopharmaceuticals
Isotope
Source
T1/2
Energy
(keV)
Use
Comment
131I (NaI)
Reactor
8.1 Days
γ: 364
β: 606
imaging
uptake
therapy
high dose
β-emission
123I(NaI)
Cyclotron
13.3 h
159
best
expensive
poorly available
99mTc(99mTcO4)
Generator
6 h
140
daily routine
cheap
low dose
2018/6/23 12

13. Thyroid scintigraphy - dosimetry
Radiophar- maceutical
Administered activity (MBq)
Organ receiving the largest radiation dose
(mGy/MBq)
131I
1.8-7,4 p.o.
210(thyroid)
123I
p.o.
1.9 (thyroid)
99mTCO4
i.v.
0.06(upper large intestine)
ADULTS
Radiophar-
maceutical
Administered activity (MBq/kg)
Organ receiving the largest radiation dose
(mGy/MBq)
131I
p.o.
1100(thyroid)
123I
p.o.
9.8 (thyroid)
99mTCO4
1-5 i.v.
0.21(upper large intestine)
CHILDREN 13

14. Thyroid imaging – instrumentation
planar gamma camera
SPECT
collimator
pinhole (magnification, but distortion)
parallel, long holes (snout-nosed) – special for thyroid
workup of acquired data: software
background subtraction
filtering 14

15. Time of acquisition after
Thyroid imaging – acquisition
planar: A-P view, sitting or supine position
upper border: submandibular gland
lower border: jugulum
large field of view: in case of suspected retrosternal spread or ectopic thyroid
RAO, LAO
marker: sternal notch (thyroid cartilage, nodules)
Radiopharmaceutical
Time of acquisition after
administration
Minimal count number
131I
24 hours
50 000
123I
2-4 hours
99mTcO4
15-30 min (i.v.) 15

16. Normal thyroid scintigraphy
normal size
homogenous appearance
sharply defined borders
straight or convex
lateral margins 16

17. Non-visualizing thyroid
Low thyroid uptake
Thyroiditis
Suppressing medication
Surgical or radioiodine ablation 17

18. Thyroid hot nodule 18

19. Thyroid cold nodule 19

20. Multinodular goiter 20

21. Autoimmune thyroid disease is a spectrum
Hyperthyroidism
Grave’s disease
Euthyroidism
Hypothyroidism
Hashimoto’s disease

22. Diffuse goiter
Graves Disease 22

23. Congenital Thyroid Disease
1 month-old with TSHs 52.3 µIU/ml.
Thyroid imaging study reveals radiotracer uptake in the neck, in the expected location and configuration of the thyroid gland.
Dyshormonogenesis. 23

24. Congenital Thyroid Disease
24 days old with TSHs > 60 µIU/ml and T4 < 0.25 µg/dl.
A Tc-99m study reveals there is no radiotracer uptake in the neck
Agenesis. 24

25. Iodine scintigraphy for differentiated thyroid carcinoma (DTC)
131I whole body scintigraphy after ablative radioiodine therapy – to detect the presence and location of functioning thyroid tissue (cancer), recurrences and/or metastases
DTC (papillary, follicular adenocarcinoma) therapy:
surgery (possible total thyroidectomy)
ablative radioiodine therapy – posttherapeutic whole body scan
suppressive LT4 medication
follow up:
neck US
serum thyroglobulin level
whole body 131I scintigraphy 25

26. Iodine scintigraphy for DTC
Anterior Posterior
Anterior Posterior
2018/6/23 26

27. Parathyroid scintigraphy
Hyperparathyroidism (HPT): high PTH level
primary: serum Ca2+ ↑ and PTH ↑ – usually adenoma or carcinoma
secondary: serum Ca2+ ↓ and PTH ↑ – usually renal
failure → parathyroid hyperplasia
tertiary: after secondary HPT one or more of the hyperplastic
parathyroid glands become autonomous → like primary
Diagnosis: 1. laboratory (serum Ca2+, PTH)
2. localisation of hyperfunctioning gland(s) – scintigraphy
Therapy: surgery, (medical: calcimimetics)
Purpose of parathyroid scintigraphy:
localisation of parathyroid adenoma (or multiglandular disease)
radio-guided surgery 27

28. Parathyroid scintigraphy
99mTc-MIBI (sestamibi): uptake both in parathyroid and
thyroid tissue
affinity to mitochondria – accumulation in tissues with high
density of cells, high energy metabolism (e.g. malignancies)
Techniques:
dual-phase: 99mTc-MIBI washout
dual-isotope: 99mTc-MIBI - 99mTc-pertechnetate subtraction 28

29. Parathyroid scintigraphy
Basics:
99mTc-MIBI accumulates both in thyroid and parathyroid
hyperfunctioning tissue
99mTc-pertechnetate accumulates only in thyroid
99mTc-MIBI - 99mTc-pertechnetate neck scintigraphy image digital
subtraction → hyperfunctioning parathyroid
Other radiopharmaceuticals:
instead of 99mTc-MIBI: 99mTc-tetrofosmin, 201TlCl
instead of 99mTc-pertechnetate: 123I
Dose: MIBI: MBq, pertechnetate: MBq
Acquisition: sequential (both sequence is acceptable)
1. pertechnetate, 2. MIBI – patient in the same position
1. MIBI, 2. MIBI washout, 3. pertechnetate – patient gets up in between 29

30. Parathyroid scintigraphy
99mTc-MIBI dual-phase imaging
15 min H

31. Parathyroid adenoma

32. Parathyroid adenoma

33. Adrenomedullar scintigraphy
Radiopharmaceutical:
MIBG (metaiodobenzylguanidine)
structurally resembles norepinephrine
active uptake by neuroendocrine cells, stored in
neurosecretory granules
accumulation in cells of sympathoadrenal system and other neuroendocrine cells (chromaffin, APUD, GEP, DNS) and tumours (carcinoid)
labeled with
123I : diagnosis (γ-emission)
131I : diagnosis, therapy (γ + β-emission) 33

34. Adrenomedullar scintigraphy: Indications
detection, localisation, staging, follow up
pheochromocytoma
neuroendocrine tumours: paraganglioma, neuroblastoma,
ganglioneuroma, etc.
carcinoid tumours
medullary thyroid carcinoma (MTC)
Merkel cell tumour of the skin
tumour uptake – isotope therapy planning
evaluation of tumour response to therapy
sympathetic innervation of heart, lung, salivary glands 34

35. MIBG scintigraphy: Pheochromocytoma
Anterior Posterior
A 12 year-old girl who was investigated for a hypertension.
Scintigraphy demonstrated a heterogeneous focus of increased tracer uptake in the right adrenal mass identified on MR. 35

36. MIBG scintigraphy: Neuroblastoma
Anterior Posterior
A 5 month-old baby who was investigated for an abdominal mass.
Scintigraphy showed a left adrenal mass and an enlarged liver with tumoral infiltration. 36

37. 2018/6/23 37