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Flashcards in Nucs Deck (30)
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1
Q

Mo-99 is the mother isotope for elution of Tc-99m

what is used to test for breakthrough in the eluate?

A

Dose calibrator

When eluting a Tc-99m generator, the mother isotope Mo-99 can contaminate the eluate. It is required to test for Mo-99 breakthrough in each eluate

2
Q

what effect does glucagon have on peristalsis and vasodilation?

A

decreases peristalsis and increases vasodilation

3
Q

What is the T1/2 of Rb 82, what is it used for

A

Rb-82 is used as a cardiac perfusion agent and produced from a Sr-82/Rb-82 generator. The physical half-life of Rb-82 is 75 seconds.

4
Q

History of thyroid cancer, elevated thyroglobulin and negative I131 whole body survey. What exam can you do?

A

PET can be used to look for mets

5
Q

what is the critical organ in a hepatobiliary scan?

A

gallbladder wall

6
Q

If you double your matrix size by how much does your # of pixels increase?

A

4x

Remember that the smaller the pixel the less counts per pixel which increase STN

7
Q

What type of scan?

A

Octreoscan

avid lesion in the pancreas

most likely islet cell tumor like gastrinoma or insulinoma

could also be carcinoid (more rare)

8
Q

21M without trauma

A

Osteosarcoma.

with MR to help we see soft tissue extension and cortical breakthrough

Ewing and other small round blue cell tumors are also in diffx (or smoldering infx) but less likely based on age

9
Q

dipyramidole mechanism of action?

A

Indirect vasodilator for coronary arteries

acts via preventing reuptake and deamination of adenosine—> increases tissue levels of adenosine

10
Q

Which drug limits release of pertechnetate by gastric mucosal cells and thus enhances sensitivity for meckel’s scan?

A

cimetidine (H2 blockers)

11
Q
A

Superscan 2/2 prostate mets

Metabolic superscans usually affect entire skeleton while metastatic are more likely to be axial and proximal appendicular skeleton

breast and prostate most likely to cause superscan

12
Q

what drug causes dose related increase in heart rate, blood pressure, and myocardial contractility?

A

Dobutamine

direct B1 and B2 activity

Dobutamine increases regional myocardial blood flow

secondary pharmacologic stressor, recommended only in patients who cannot undergo exercise stress and who also have contraindications to pharmacologic vasodilator.

13
Q

what med changes might you make before a 131I- NaI (sodium iodide) scan after ablation/treatment for thyroid cancer?

A

either decrease dose of levothyroxine (to increase endogenous TSH) or give thyrotropin alpha

14
Q

What is the half life of Xe133?

Photon Energy?

A

5.3 days

gamma energy: 81 keV

15
Q

What measures the biological damage caused by ionizing gamma radiation exposure?

A

Roentgen equivalent man

—> REM

term for dose equivalence, equals the biological damage that would be caused by 1 radiation absorbed dose (RAD). The REM accounts for the fact that not all types of radiation are equally effective in producing biological change or damage. That is, the damage from 1 RAD deposited by beta radiation is less than that caused by 1 rad of alpha radiation.

16
Q

Half life of Thallous Chloride?

TI-201

A

73 hours

17
Q

Dose calibrator has what checked on installation or anytime it is moved?

A

Geometry

Geometry assesses the effect of sample volume &/or configuration in a vial or syringe on the measurement of a sample’s activity.

18
Q

What are the advantages of In III WBC vs Tc99m HMPAO for infection/inflammation?

A

Tc-99m HMPAO labeled leukocyte scintigraphy: advantages of earlier and shorter imaging times, lower absorbed radiation dose, and a smaller blood sample for labeling leukocytes.

In-111 leukocyte scintigraphy: preferred in the abdomen/pelvis, because there is normally no excretion into gastrointestinal or urinary tracts. (Fewer false positives)

19
Q

Half life of Sodium Fluoride F18

A

109 minutes

Same as F18 used for PET (with FDG label)*

20
Q

Mechanism of action Tc99m Tetrofosmin

A

Passive diffusion

amount delivered to myocytes is 2/2 perfusion

21
Q

What radiotracer used to evaluate renal cortex?

A

Tc99m DMSA

Renal cortical imaging—differentiates scar from pyelonephritis

DMSA works by tubular (cortical) binding

22
Q

Half life of I131 NaI

I123?

A

I 131 = 8 days, 364 keV

I123 = 13 hours, 159 keV

23
Q
A

Sacral insufficiency fracture

2/2 normal force applied to demineralized bone

Causes: postmenopausal osteoporosis, disuse osteopenia, steroids, metabolic bone disease, testicular atrophy/testosterone deficiency, and prior radiation to region.

24
Q

In which type of nucleus does position decay occur?

Beta particle emission?

A

proton rich nucleus (neutron poor)

Beta particle emission happens in neutron rich nuclei

25
Q

Perfusion agent for V/Q scans?

Ventilation choices?

A

Perfusion: Tc99m MAA

Ventilation:

Either Tc99m DTPA—multiple projections, renal filtration

OR

Xe-133– 1-3 views, washes out, requires a special Xenon trap and is fat-soluble and has high sensitivity for COPD

26
Q

What tracer was used?

A

Ga^68 DOTATATE

Binds SSTR2 receptors

27
Q

What does Nuclear Regulatory Commission (NRC) regulation 10 CFR Part 35 deal with?

A

Medical use of by-product radioactive material

10 CFR Part 35 is titled “Medical Use of By-product Material,” and is a key regulation for Nuclear Medicine Authorized Users and physicians performing radiation therapy

28
Q

what med is used to evaluate chronic cholecystitis?

A

Syncalide

(c terminal octopeptide of cholecystokinin)

GB ejection fraction should beat at least 38%

29
Q

recommendations for breastfeeding and I-131?

A

Cessation prior to therapy

Issues include:

radiation to the mother’s breast as lactating breasts accumulate more of the I-131. radiation dose to the child due to proximity of the child to the breast during feeding, actual I-131 expressed in breast milk.

For these reasons, the recommendation is to stop breastfeeding several weeks (4-6) prior to radioactive ablation.

30
Q

Is this pattern typical for graves?

A

No, would be diffusely enlarged and homogenous uptake without nodules (although CAN have superimposed nodules)

Toxic multinodular goiter, toxic adenoma, hashimoto’s toxicosis, endemic goiter can all look like this