Thyroid radio Flashcards
Technetium-99m has an uptake mechanism similar to _______
Iodine
What type of image do we get in scintigraphy ?
2D
What are the techniques used in thyroid ?
US
Scintigraphy
CT/MRI - useful only in some px
what do we assess with US on thyroid ?
Evaluation of the :
** number of lesions
** Sites
** Calcifications
vascular evaluation of thyroid can be done with ?
color doppler
What radioisotope is indicated for diagnosis of Grave’s disease ?
Tc 99m-Pertechnetate
plummers diseases appears as
solitary hot nodule
what is the distribution seen with Tc 99m pertechnetate with graves disease ?
Homogenous distribution
what is the distribution seen with Tc 99m pertechnetate with multinodular goiter disease ?
Inhomogeneous distribution
what is the distribution seen with Tc 99m pertechnetate with subacute thyroiditis ?
Markedly reduced uptake
what tracer is used for scintigraphy ?
Iodine 131- gamma emitter, has diagnostic use
I-131 is selectively taken up by what cells ?
Thyroid follicular cells with the help of sodium-iodine symporters
what type of emitter is Iodine-131 ?
both Beta and Gamma
what is the main thing we check for with scintigraphy of the thyroid ?
How the nodules appear.
What is the first line indication test for most patients with UNCERTAIN etiology of Thyrotoxicosis ?
Thyroid Scintigraphy
why Iodine-131 is preferred for therapy ?
Longer half-life
What Radiotherapy used for benign and malignant thyroid disease ?
Iodine 131
What is the use of Doppler in thyroid nodule imaging ?
For vascularization (combined with US)
what does increased vascularization means on doppler when checking thyroid nodule ?
Usually indicate malignancy
1st level instrument for thyroid diagnosis ?
US
what is the 2nd level study for the thyroid ?
Scintigraphy
what is the procedure we perform in case we want to study one of the nodules we find ?
Fine needle aspiration, but it is not diagnostic for Pappilary K.
what is the frequency of the thyroid US ?
linear high frequency 7.5 Mhz
how will appear benign nodular lesion on color Doppler ?
Hyper-echogenic signal
Regular nodule margin
how will appear Malignant nodular thyroid lesion on color Doppler ?
Hypo-echogenic signal
Faded margins
what other radionuclides can we use for Thyroid except Tc-99 ?
Tetro-fosmin
Sestamibi
what does thyroid scintigraphy allows us to highlight ?
- hyper/hypo functioning of the nodule
- Ectopic thyroid tissue
- Metastasis
hot nodule on thyroid scintigraphy is probably
benign
Cold nodule on scintigraphy is probably
Neoplasia
what are the most common places of metastasis for thyroid cancer ?
Pelvis and chest
In what cases do we use PET-CT for thyroid K ?
When it’s poorly differentiated and with high levels of Thyroglobulin
except FDG, what else can we use for PET in thyroid ?
Iodine-124
Papillary thyroid carcinoma metastasizes by ;
Lymphatic route
Follicular thyroid cancer metastasizes to ;
Blood, lung, and bone.
