Ch. 14 Thyroid, Parathyroid, and Salivary Gland

A technologist is performing a thyroid uptake with 123I sodium

iodide. The capsule is counted before being administered to

the patient, and 850,192 cpm is obtained. Six hours after

swallowing the capsule, the counts from the patient’s neck are

116,239 and from the thigh 34,982. Background for the

uptake probe is 239 cpm, and the 6-h decay factor for 123I is

0.730. What is the 6-h uptake?

(a) 7.0%

(b) 9.5%

(c) 13.1%

(d) 18.7%

(C) 13.1%

What will the effect be if a technologist places the uptake probe over the proximal thigh when counting background in

the patient?

(a) The background will be falsely elevated.

(b) The background will be falsely decreased.

(c) The calculated uptake will decrease.

(d) (a) and (c).

(e) (b) and (c).

d) (a) and (c).

Which of the following dietary supplements will affect thyroid uptake?

(a) Vitamin A

(b) Vitamin B

(c) St. John’s wort

(d) Kelp tablets

(e) Lactobacillus

(d) kelp tablets

Which of the following will not affect thyroid uptake?

(a) Iodinated contrast media

(b) Propylthiouracil

(c) Thyroid hormones

(d) Beta-blockers

(d) Beta blockers

Thyrotropin is also known as:

(a) TRH

(b) TSH

(c) T3

(d) T4

(b) TSH

Which of the following statements is not true?

(a) TRH stimulates the release of TSH by the anterior pituitary.

(b) Release of T3 is inhibited by elevation of T4.

(c) T3 and T4 are both hormones which are manufactured and released by the thyroid.

(d) TRH is synthesized in the hypothalamus.

(b) Release of T3 is inhibited by elevation of T4.

Most people have four parathyroid glands.

(a) True

(b) False

(a) True

The salivary glands include:

(a) Parotid glands

(b) Sublingual salivary glands

(c) Submaxillary salivary glands

(d) All of the above

(e) (b) and (c) only

(d) All of the above

Which of the following are used to image the parathyroid?

(a) 99mTc pertechnetate

(b) 99mTc sestamibi

(c) 201Tl chloride

(d) (a) and (b)

(e) (b) and (c)

(e) (b) and (c)

The collimator attached to a thyroid uptake probe is:

(a) Converging

(b) Diverging

(c) Pinhole

(d) Flat field

(e) Low energy all purpose

(d) Flat field

Which of the following is part of the preparation for a thyroid uptake?

(a) NPO from midnight.

(b) Administer Lugol’s solution.

(c) Have the patient void before administration of radiopharmaceutical.

(d) Withhold caffeine-containing beverages for 24 h prior to examination.

(e) None of the above.

(a) NPO from midnight

When performing a thyroid uptake, the technologist neglects to count the capsule before it is administered to the patient. What are the implications?

(a) It will not be possible to calculate uptake values.

(b) An identical capsule must be counted in a neck phantom in order to obtain uptake values.

(c) No decay factor will be used in the calculation of uptake values.

(d) None of the above.

(e) (b) and (c)

(e) (b) and (c)

While taking information from a patient who is scheduled for a thyroid uptake and scan with 123I sodium iodide, a technologist learns that he or she has been taking Cytomel that week. What does this mean?

(a) Nothing; thyroid uptake will not be affected by Cytomel.

(b) Imaging may still be obtained using 201Tl chloride.

(c) Both the uptake and scan can be performed using 131I.

(d) Study should be performed as ordered, but the uptake will be inaccurate.

(e) None of the above.

(b) Imaging may still be obtained using 201Tl chloride.

What is the method of localization of 99mTc pertechnetate in

the thyroid?

(a) Sequestration

(b) Active transport

(c) Receptor binding

(d) Diffusion

(e) Phagocytosis

(b) Active transport

Imaging of the thyroid takes place:

(a) Approximately 20 min after injection of 99mTc pertechnetate

(b) 6 h after administration of an 123I sodium iodide capsule

(c) 24 h after administration of an 123I sodium iodide capsule

(d) All of the above

(d) All of the above

Which of the following will not optimize images of the thyroid?

(a) Use of a pinhole collimator

(b) Having the patient avoid swallowing during image acquisition

(c) Hyperextending the neck

(d) Placing a radioactive marker on the xiphoid process

(d) Placing a radioactive marker on the xiphoid process

A linear area of activity in the esophagus is seen on a thyroid image taken using 99mTc pertechnetate. What does it represent?

(a) Sublingual thyroid

(b) Parathyroid

(c) Pertechnetate that was secreted by the salivary glands and swallowed

(d) Parotid gland

(c) Pertechnetate that was secreted by the salivary glands and swallowed

The use of 131I for thyroid imaging:

(a) Is common if an uptake is also planned

(b) Is typically only used when scanning the whole body for metastatic thyroid disease after thyroidectomy

(c) Delivers a lower radiation dose to the thyroid than does

99mTc pertechnetate, since only μCi amounts are administered

(d) All of the above

(b) Is typically only used when scanning the whole body for metastatic thyroid disease after thyroidectomy

A patient receives both 3 mCi of 201Tl chloride and 5 mCi of 99mTc pertechnetate, and pinhole images of the neck are taken after each administration. If the pertechnetate image is subtracted from the 201Tl image, the activity that remains represents:

(a) Thyroid

(b) Parathyroid

(c) Salivary glands

(d) Hypothalamus

(e) Nonfunctioning thyroid tissue

(b) Parathyroid

The salivary glands may be imaged using:

(a) 3 mCi of 201Tl

(b) 5 mCi of 99mTc sestamibi

(c) 5 mCi of 99mTc pertechnetate

(d) 200 μCi of 123I sodium iodide

(c) 5 mCi of 99mTc pertechnetate

Which of the following describes delayed images at 2–3 h after injection of 99mTc sestamibi?

(a) Persistent activity in the normal thyroid with complete washout of activity in the parathyroid

(b) Persistent activity in parathyroid adenomas and decreased activity in the thyroid relative to early images

(c) Persistent activity in hyperfunctioning thyroid tissue and no activity in the parathyroid or salivary glands

(d) Activity in the salivary glands and normal parathyroid tissue

(b) Persistent activity in parathyroid adenomas and decreased activity in the thyroid relative to early images

A hot nodule on a thyroid image will most likely be benign.

(a) True

(b) False

(a) True

Which of the following are symptoms of hyperthyroidism?

(a) Exophthalmos

(b) Bradycardia

(c) Cold intolerance

(d) All of the above

(e) (b) and (c)

(a) Exophthalmos

The highest doses of therapeutic 131I are given to patients with:

(a) Grave’s disease

(b) Toxic multinodular goiter

(c) Thyroid cancer

(d) Chronic thyroiditis

(c) Thyroid cancer

A patient with a 45% uptake of 123I sodium iodide at 24 h is:

(a) Euthyroid

(b) Hyperthyroid

(c) Hypothyroid

(d) Athyroid

(b) Hyperthyroid

The part of the thyroid that lies anterior to the trachea and is often not seen on thyroid imaging is the:

(a) Right lobe

(b) Left lobe

(c) Isthmus

(d) Parathyroid

(e) Superior thyroid notch

(c) Isthmus

On anterior-view thyroid images taken using 123I sodium iodide, the right lobe appears to be larger than the left. The explanation for this is:

(a) A right hemigoiter.

(b) A hypofunctioning left lobe.

(c) A normal finding.

(d) The patient’s head was turned slightly to the left.

(e) The patient’s head was turned slightly to the right.

(c) A normal finding.

Iodine is needed for the thyroid gland to synthesize T3 and T4.

(a) True

(b) False

(a) True

About 90% of the thyroid hormone secreted into the blood is in the form of:

(a) Thyroxine

(b) Triiodothyronine

(c) Thyroglobulin

(d) Thyrotropin

(e) Iodotyrosine

(a) Thyroxine

A patient with hyperparathyroidism will have:

(a) Myxedema

(b) Exophthalmos

(c) Cold nodules in the thyroid

(d) Increased fracture risk

(e) More than four parathyroid glands

(d) Increased fracture risk

Why is a 6-h thyroid uptake obtained?

(a) In case the patient does not show up the following day for the 24-h uptake

(b) To detect hyperthyroidism when the turnover is so rapid that the 24-h uptake may be normal

(c) In case an error is made in the calculation of the 24-h uptake

(d) So that the patient can resume eating

(b) To detect hyperthyroidism when the turnover is so rapid that the 24-h uptake may be normal

Which patient will have the longest wait before an accurate thyroid uptake with 123I can be obtained?

(a) A patient who had a myelogram

(b) A patient who took Synthroid

(c) A patient who had an IVP

(d) A patient who was given Lugol’s solution

(e) A patient who took kelp tablets

(a) A patient who had a myelogram

To stimulate secretion during salivary gland scintigraphy, which of the following is often used?

(a) 99mTc sestamibi

(b) Lemon juice

(c) Lugol’s solution

(d) Captopril

(e) Furosemide

(b) Lemon juice

Ectopic thyroid tissue may occur:

(a) In the pelvis

(b) In the neck

(c) In the mediastinum

(d) At the base of the tongue

(e) All of the above

(e) All of the above

If the salivary glands are not seen on a thyroid scan obtained with the use of 99mTc pertechnetate, it may mean:

(a) That the thyroid is hyperfunctioning and trapped the majority of the tracer

(b) That the salivary gland function is compromised

(c) That the salivary glands lie inferior to the thyroid and cannot be seen on anterior images

(d) (a) and (b)

(e) (b) and (c)

(d) (a) and (b)

When would a low-energy all-purpose collimator be used for thyroid examinations?

(a) During uptake counting

(b) When searching for ectopic thyroid with 131I sodium iodide

(c) When performing whole body with 131I sodium iodide scanning after thyroidectomy

(d) When obtaining a blood pool image of the thyroid with 99mTc pertechnetate to differentiate cystic and solid masses

(e) All except (a)

(d) When obtaining a blood pool image of the thyroid with 99mTc pertechnetate to differentiate cystic and solid masses

Radioactive iodine and 99mTc pertechnetate cross the placenta.

(a) True

(b) False

(a) True

A technologist performs a thyroid uptake using an identical capsule to the one administered to the patient as a standard. Given the following data obtained 6 h after the capsule was swallowed, what is the uptake?

Neck 55,213 cpm

Thigh 2085 cpm

Standard 345,987 cpm

Background 48 cpm

(a) 1.5%

(b) 15.4%

(c) 16.6%

(d) 30.7%

(b) 15.4%

An indication for a thyroid uptake is for use in calculation of the amount of radioiodine therapy for hyperthyroidism.

(a) True

(b) False

(a) True

When performing a thyroid scintigraphy, Tc-99 m pertechnetate is preferred when:

(a) Patient is not able to swallow radioiodine pill.

(b) Patient had CT scan last week with IV contrast.

(c) Patient is taking amiodarone.

(d) All of the above.

(d) All of the above.

When performing a radioiodine thyroid scintigraphy for a patient with suspected hyperthyroidism, a technologist found that the thyroid radioiodine uptake is close to zero, and there is only background activity on the images. Which of the following is correct?

(a) The imaging time should be extended until good image of the thyroid gland is seen.

(b) There is likely a technical problem with the gamma camera.

(c) Patient should be re-dosed as the findings are not consistent with the provided history of hyperthyroidism.

(d) Talk to your nuclear medicine physician.

(d) Talk to your nuclear medicine physician.

When performing a radioiodine thyroid scintigraphy, the major advantage of using 131I is:

(a) Lower dose

(b) Less radiation exposure

(c) Better imaging quality

(d) Higher sensitivity for detecting occult lesions

(d) Higher sensitivity for detecting occult lesions

What is the typical dose for a parathyroid scan?

(a) 20 mCi 99mTc-sestamibi

(b) 30 mCi 99mTc-sestamibi

(c) 10 mCi 99mTcO4−

(d) 20 mCi 99mTcO4−

(a) 20 mCi 99mTc-sestamibi

What is the route of administration for a parathyroid scan dose?

(a) Orally

(b) 10-min IV infusion

(c) Intravenous bolus

(d) Intramuscular

(c) Intravenous bolus

Dual-isotope parathyroid imaging uses what tracers?

(a) 123I and 131I

(b) 99mTc sestamibi and 123I

(c) 99mTcO4− and 131I

(d) 99mTc sestamibi and 131I

(b) 99mTc sestamibi and 123I

What is the typical dose of 99mTc pertechnetate for a thyroid scan?

(a) 0.5 mCi

(b) 1.0 mCi

(c) 5.0 mCi

(d) 20.0 mCi

(c) 5.0 mCi

131I dose for a diagnostic thyroid scan?

(a) 100 uCi

(b) 200 uCi

(c) 500 uCi

(d) 1 mCi

(a) 100 uCi

131I decays by which method?

(a) Alpha decay

(b) Beta decay

(c) Gamma decay

(b) Beta decay

What is the energy of 131I?

(a) 140 keV

(b) 364 keV

(c) 168 keV

(d) 511 keV

(b) 364 keV

Whole-body 131I imaging is performed with what dose?

(a) 2–5 mCi 131I

(b) 200 uCi 123I

(c) 200 uCi 131I

(d) 2–5 mCi 123I

(a) 2–5 mCi 131I

What is the half-life of 123I?

(a) 6 h

(b) 13 h

(c) 73 h

(d) 8 days

(b) 13 h

Because 99mTcO4− is trapped but not organified by the thyroid, imaging should begin __________ after injection.

(a) At 10 min

(b) Within 30 min

(c) At 4 h postinjection

(d) At 1 day postinjection

(b) Within 30 min

Thyroid scintigraphy is utilized to evaluate:

(a) Thyroid function

(b) Functional status of nodules

(c) Size and location of thyroid tissue

(d) All of the above

(d) All of the above

99mTcO4− is administered

(a) Orally

(b) Intravenously

(c) Intramuscularly

(b) Intravenously

How is 123I administered?

(a) Intravenously

(b) Intramuscularly

(c) Orally

(c) Orally