The second part
Imaging agents and their futrers, imaging methods
Imaging agents and their characteristics
Iodine-131(131I):
❖ Long physical half-life(8.04d) ❖ β-rays occupy 90%,r-rays only occupy 10% of its emission ❖ The energy of principal r-ray is high(364 Kev) ❖ A relatively high irradiation dose to the thyroid and whole-body ❖ Easily obtained and with lower cost ❖ Mainly be used for detecting ectopic thyroid tissue and
Sometimes tomographic imaging or SPET/CT images fusion is necessary to identify suspicious focus shown in planar imaging.
Fig1.Static imaging of thyroid
Fig2.Dynamic imaging of thyroid
4).The posture of imaging
Supine , neck extended, and detecting in anterior ,sometimes in left or right anterior oblique posture.
metastasis of thyroid carcinoma ❖ The scanning must be performed at least 24h after oral 131I