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14 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What are the 2 general classifications of diseases related to thyroid gland?
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functional (hyper or hypothyroidism)
structural (anatomical changes, nodules, enlargement) |
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Can a physician learn all they need to know from a nm scan to do a proper diagnosis of a thyroid condition?
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no they must integrate the findings from the clinical exam, lab results and the nm procedures
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What is the patient prep for a thyroid scan?
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no medications thyroid hormones and anti-thyroid agents and no food containing iodine
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When thyroid tissue migrates to other than the usual location it is called ________ thyroid
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When thyroid tissue migrates to other than the usual location it is called lingual thyroid
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What is the formula for measuring thyroid uptake before doing scan?
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pt count - bkgrd/capsule count-bkgrd x100
what is the normal value? |
10-35% for 24 hrs and 6-18% for 4 hrs
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What is the thyroid updake with the following data:
thyroid count=56,528 background=367 std capsule=1,284,766 room background=105 24 hr decay factor=.284 |
56,528-367/(1,284,766 x .284) - 105 x 100
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15%
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When imaging thyroid with Tc99m pertechnetate how much is the dose, what is the imaging time?
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2-10 mCi, 15-30 min post inj, 100-200k counts or 5 min
what is the disadvantage of using Tc compared to I-123? |
Tc localizes in the iodine trapping mechanism of the acinar cell and does not give information about organification, storage, or or hormone release functions of the thyroid gland
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What is the protocol for imaging with I-123
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pt given 100 or 200 microcurie capsule, can image at 4-6 hrs but usually at 24 hrs
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What is stunning?
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with I-131 a decrease in radioiodine uptake by residual thyroid and/or metastatic thyroid carcinoma following the administration of scanning doses greater than 2 mCi
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list 4 main properties seen in a normal thyroid scan
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1. homogenous uptake of radiopharmaceutical with well defined borders.
2. each lobe is ellipsoidal in shape with lateral margins typically convex. 3. the isthmus is variable and typically not prominent in adults. 4. a paramidal lobe can be visualized in approximately 1/5 normal pts, commonly seen in graves disease |
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Elevated levels of plasma thyroid hormones, goiters, graves disease, toxic anenoma, TSH secretion are indications of what condition?
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hyperthyroidism
what would be uptake values after 6hrs, 24 hrs? |
6hrs - 85%
24hrs - 70% |
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What is the condition when the following exist: diminished thyroid hormone, increased serum levels of TSH, decreased serum levels of T3 and T4
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hypothyroidism
what can this cause? |
Thyroiditis, autoimmune (Hashimotos) enlargement to compensate for impaired homonogenesis
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True of false: most thyroid nodules are benign?
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True, most cancers present as a single or dominant nodule, multiple nodules decrease the likelihood of cancer
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list some errors that can occur in thyroid imaging
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1. variations in distance from neck to detector.
2. inappropiate neck phantom 3. improper centering of probe over patient's neck 4. background variation or radiation in adjacent areas 5. recent administration or other nuclides |
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