Radioisotopic investigations in

endocrinology

Indications: thyroid scintigraphy

hyperthyroidia thyroid nodes toxic adenoma thyroid neoplasia hipothyroidia thyroiditis

- pregnancy

Radiotracers:

99mTc , 123I, 131I uptake mechanism: active uptake; iodine =

organification, hormones synthesis

Image types:

planars (A, P, profil, oblics…)

tomographic Colimator:

- paralel

- pin-hole

Interpretation: Limits, shape dimensions intensity(hiperfixation/hipofixation) uniformity(nodes?) Quantification: rate

node/normaltissue; LD/LS…; thyroid radiotracer uptake (%).

99mTcO4-scintigram:

normal thyroid

scintigraphic images semeiology:

omogen difuse hyperfixation = Basedow d.

difuse hypofixation = hypothyroidia? Node with no uptake = liquid kyst?/

neoplasia? Node with hyperfixation = toxic

adenom? Multiple nodes, hiperfixation… =TMNG

99mTcO4-

Conclusion: Basedow disease

Node with no uptake

(LTD)

Node with no uptake (LTD)

Neoplasia:A - node with hypofixation LTS (99mTc);B - node with no fixation LTS (123I).

99mTc / 123I (131I)

99mTc / 201Tl

99mTcO4-:

multinodular goiter

TcO4- uptake: 2,8% (n: 2 - 6%)

T4(RIA): 9,4 (n: 6,5-13,5)

Important

Iodine alergy do not c.i. the iodine scintigram

complementar investigations: TSH dosage, T3, T4; radioiodine uptake

131I whole body scintigram:

Thyroid neoplasia with multiple metastases (cervical, lung)

131I:

Basedow disease

Precautions:

Different drugs which contain iodine may determine false images (ex. Amiodarone, contrast iodine substances), ATS, thyroid hormones...

3- 6 weeks.

- scintigrafia glandelor suprarenale:

dg.+ al feocromocitomului (MIBG)d.d. adenom Conn / hiperplazie suprarenal\(analog de colesterol marcat cu 131I)

- scintigrafia glandelor paratiroide: dg. de adenom paratiroidian, dg. neoplasm paratiroidian (99mTc MIBI…)

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