Distribution and dynamics of (99m)Tc-pertechnetate uptake in the thyroid and other organs assessed by single-photon emission computed tomography in living mice.
BACKGROUND
(99m)Tc pertechnetate is a well-known anion, used for clinical imaging of thyroid function. This gamma emitter is transported by the sodium iodide symporter but is not incorporated into thyroglobulin. Scintigraphy using (99m)Tc pertechnetate or (123)iodide represents a powerful tool for the study of sodium iodide symporter activity in different organs of living animal models. However, in many studies that have been performed in mice, the thyroid could not be distinguished from the salivary glands. In this work, we have evaluated the use of a clinically dedicated single-photon emission computed tomography (SPECT) camera for thyroid imaging and assessed what improvements are necessary for the development of this technique.


METHODS
SPECT of the mouse neck region, with pinhole collimation and geometric calibration, was used for the individual measurement of (99m)Tc pertechnetate uptake in the thyroid and the salivary glands. Uptake in the stomach was studied by planar whole-body imaging. Uptake kinetics and biodistribution studies were performed by sequential imaging.


RESULTS
This work has shown that thyroid imaging in living mice can be performed with a SPECT camera originally built for clinical use. Our experiments indicate that (99m)Tc pertechnetate uptake is faster in the thyroid than in the salivary glands and the stomach. The decrease in (99m)Tc pertechnetate uptake after injection of iodide or perchlorate as competitive inhibitors was also studied. The resulting rate decreases were faster in the thyroid than in the salivary glands or the stomach.


CONCLUSIONS
We have shown that a clinically dedicated SPECT camera can be used for thyroid imaging. In our experiments, SPECT imaging allowed the analysis of (99m)Tc pertechnetate accumulation in individual organs and revealed differences in uptake kinetics.
Franken
Philippe R
PR
Transporters, Imaging and Radiotheraphy in Oncology (TIRO), Commissariat Energie Atomique Direction des Sciences du Vivant (DSV), Institut de Biologie Environementale et Biotechnologie (iBEB), Service de Biochimie et Toxicologie Nucléaire (SBTN), Centre Antoine Lacassagne, University of Nice Sophia Antipolis , Nice, France .
Guglielmi
Julien
J
Vanhove
Christian
C
Koulibaly
Malick
M
Defrise
Michel
M
Darcourt
Jacques
J
Pourcher
Thierry
T
D000818:Animals; D005753:Gastric Mucosa / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009333:Neck / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012469:Salivary Glands / Q000000981:diagnostic imaging / Q000378:metabolism; D012974:Sodium Iodide; D013670:Sodium Pertechnetate Tc 99m / Q000493:pharmacokinetics*; D013270:Stomach / Q000000981:diagnostic imaging; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000378:metabolism*; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon; D051598:Whole Body Imaging
D019275:Radiopharmaceuticals; D013670:Sodium Pertechnetate Tc 99m; D012974:Sodium Iodide