Nuclear medicine procedures and safety

44 Gulf Prometric Radiographer (DHA, DOH, MOH, SCFHS, QCHP) practice questions on Nuclear medicine procedures and safety, part of Nuclear Medicine. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Medium

   Tc-99m solution is spilled on a technologist's forearm. After removing contaminated clothing, the best skin decontamination is to:

   1. AScrub firmly with a stiff brush and strong detergent
   2. BWash gently with lukewarm water and mild soap
   3. CCover with a dressing until the activity decays
   4. DApply an alcohol-based rub and leave it to dry

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   Answer: B · Wash gently with lukewarm water and mild soap

   Skin is washed gently with lukewarm water and mild soap, working from the edge inwards, and monitored after each wash. Abrasion or hot water damages the skin and increases absorption of the radionuclide, while alcohol may drive the contamination in.

   • A: Hard scrubbing damages the skin and increases uptake.
   • C: Covering retains the contamination against the skin.
   • D: Alcohol rubs may enhance absorption and do not remove the activity.

   Remember this

   Wash skin contamination gently with lukewarm water and soap, and monitor between washes without abrading.

2. Question 2 · Medium

   After an IV injection of Tc-99m MDP for a routine whole-body bone scan, when are the delayed images usually taken?

   1. AAbout 2 to 4 hours after injection
   2. BAbout 20 minutes after injection
   3. CAbout 24 hours after injection
   4. DImmediately after injection

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   Answer: A · About 2 to 4 hours after injection

   The delay of about 2 to 4 hours lets the diphosphonate bind to bone while unbound tracer is cleared by the kidneys, giving good bone-to-soft-tissue contrast. Immediate images form the flow and blood-pool phases of a three-phase study. A 24-hour image is occasionally added in poor renal function.

   • B: At 20 minutes too much tracer remains in the soft tissues.
   • C: 24 hours is too late for routine imaging with a 6-hour half-life.
   • D: Immediate images show blood flow, not the bone uptake phase.

   Remember this

   Routine bone scan images are taken about 2 to 4 hours after Tc-99m MDP.

3. Question 3 · Medium

   A bone scan shows diffusely increased skeletal uptake with very faint kidneys and bladder activity. This pattern is known as a:

   1. AFlare phenomenon
   2. BSuperscan
   3. CCold lesion
   4. DNormal variant

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   Answer: B · Superscan

   A superscan has intense and uniform skeletal uptake, high contrast between bone and soft tissue, and little or no renal activity because most of the tracer is taken up by the bones. It is classically seen in widespread bone metastases, such as in prostate cancer, and metabolic bone disease.

   • A: Flare describes increased uptake of lesions after successful treatment.
   • C: A cold lesion is a focal area of decreased uptake.
   • D: A normal scan shows clear renal activity.

   Remember this

   superscan means diffuse bone uptake with absent kidneys.

4. Question 4 · Easy

   Tc-99m macroaggregated albumin (MAA) is used to assess:

   1. ALung perfusion
   2. BHepatobiliary function
   3. CGastric emptying
   4. DLung ventilation

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   Answer: A · Lung perfusion

   MAA particles of 10 to 90 micrometres lodge in the pulmonary pre-capillary arterioles after intravenous injection, so the distribution of activity follows pulmonary blood flow.

   • B: Hepatobiliary function uses Tc-99m mebrofenin.
   • C: Gastric emptying uses a labelled meal.
   • D: Ventilation is assessed with Tc-99m DTPA aerosol, Technegas or Xe-133.

   Remember this

   MAA shows lung perfusion.

5. Question 5 · Easy

   Which radiopharmaceutical is normally used for a routine bone scan?

   1. ATc-99m macroaggregated albumin (MAA)
   2. BTc-99m sulphur colloid particles
   3. CTc-99m mebrofenin (hepatobiliary)
   4. DTc-99m methylene diphosphonate (MDP)

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   Answer: D · Tc-99m methylene diphosphonate (MDP)

   Tc-99m MDP (or HDP) is a diphosphonate that binds to the hydroxyapatite in bone, mainly at sites of new bone formation and increased blood flow, so uptake rises where bone is being remodelled.

   • A: MAA is used for lung perfusion.
   • B: Sulphur colloid is taken up by the reticuloendothelial system.
   • C: Mebrofenin is used for hepatobiliary imaging.

   Remember this

   Tc-99m MDP is the bone agent.

6. Question 6 · Medium

   A patient has intermittent lower gastrointestinal bleeding. Why is a Tc-99m labelled red cell study useful?

   1. AIt treats the bleeding vessel by embolisation
   2. BIt needs a bleeding rate of at least 5 mL/min to show a site
   3. CIt shows bleeding only during the first 2 minutes
   4. DIt can image for hours and detect slow or intermittent bleeding

   Answer and explanation in LearnFree account

7. Question 7 · Medium

   A patient with known pulmonary hypertension is referred for a ventilation-perfusion study. What change is usually made to the MAA dose?

   1. AIncreased to 1 million particles for a clear image
   2. BLeft unchanged, whatever the patient's condition
   3. CReplaced by free pertechnetate, which gives perfusion
   4. DReduced, to about 100,000 particles

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8. Question 8 · Medium

   Before a stress myocardial perfusion study with adenosine or regadenoson, what must the patient avoid?

   1. ACaffeine-containing food and drink for at least 12 hours
   2. BSleep during the night before the examination
   3. CWater and clear fluids for at least 12 hours
   4. DAll vegetables for three days before the study

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9. Question 9 · Medium

   Following a Tc-99m sestamibi injection for a stress myocardial study, a patient is given a light fatty meal. The main purpose is to:

   1. ARaise the uptake of tracer in the myocardium
   2. BBlock free pertechnetate from entering the thyroid gland
   3. CLower the radiation dose delivered to the bladder
   4. DClear tracer from the gallbladder and nearby bowel

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10. Question 10 · Easy

    Tc-99m DMSA is used mainly to assess:

    1. ARenal cortical function and scarring
    2. BRenal drainage and obstruction of the system
    3. CLung ventilation of the upper zones
    4. DBone metabolism in the adjacent spine

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11. Question 11 · Medium

    What instruction helps reduce the bladder radiation dose after a Tc-99m MDP bone scan injection?

    1. AFast until the scan is finished, with no fluids
    2. BAvoid fluids for 4 hours after the injection
    3. CTake a laxative before the injection is given
    4. DDrink plenty of fluids and empty the bladder often

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12. Question 12 · Medium

    Tc-99m pertechnetate is used for thyroid imaging. Which statement about it is correct?

    1. AIt is trapped and organified like iodine
    2. BIt cannot show nodules as hot or cold
    3. CIt is imaged 24 hours after an oral dose
    4. DIt is trapped by the thyroid but not organified

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13. Question 13 · Hard

    Before I-123 MIBG imaging for a suspected phaeochromocytoma, the patient is given potassium iodide and some drugs are stopped. What is the reason for the potassium iodide?

    1. AIt increases MIBG uptake by the tumour
    2. BIt speeds renal excretion of the MIBG
    3. CIt prevents an adrenal crisis during imaging
    4. DIt blocks thyroid uptake of free radioiodide

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14. Question 14 · Medium

    For a thyroid uptake study, a patient taking methimazole is asked to stop it beforehand. How long is the usual period for stopping an antithyroid drug?

    1. ANo need to stop
    2. BOnly 1 hour
    3. CAbout 3 to 5 months
    4. DAbout 3 to 5 days

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15. Question 15 · Hard

    A patient vomits on the floor soon after swallowing an I-131 capsule in the treatment room. What is the best first sequence of actions for the technologist?

    1. ARestrict access, wear gloves, cover the spill with absorbent paper, call the RSO
    2. BUse a vacuum cleaner to collect the spill from the floor
    3. CWipe the floor quickly with a dry cloth, then leave the room
    4. DLeave the spill in place and wait until the following morning

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16. Question 16 · Hard

    A man has a fixed inferior wall defect on stress and rest SPECT images, and wall motion and thickening are normal on the gated images. The most probable explanation is:

    1. AA transmural infarct of the inferior wall
    2. BDiaphragmatic attenuation artefact
    3. CLeft bundle branch block
    4. DReversible ischaemia

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17. Question 17 · Medium

    In which patient is adenosine stress most clearly contraindicated?

    1. AA patient with a normal ECG and no symptoms
    2. BA patient taking a statin for high cholesterol
    3. CActive severe bronchospasm or second-degree AV block
    4. DA patient with mild hypertension under control

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18. Question 18 · Hard

    A patient with biochemical hyperthyroidism has a 24-hour radioiodine uptake of 2% (normal about 10 to 30%). Which diagnosis best fits?

    1. AToxic adenoma with an autonomous hot nodule
    2. BThyroiditis or excess thyroid hormone intake
    3. CToxic multinodular goitre with patchy autonomous areas
    4. DGraves disease with a diffusely overactive gland

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19. Question 19 · Medium

    A patient on cardiotoxic chemotherapy has repeated MUGA (gated blood pool) studies. Which tracer is used, and what is measured?

    1. ATc-99m pertechnetate; the thyroid uptake
    2. BF-18 FDG; the myocardial glucose use
    3. CTc-99m labelled red cells; the LV ejection fraction
    4. DTc-99m MAA; the pulmonary blood flow

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20. Question 20 · Hard

    A patient requires a stress myocardial perfusion study but has active wheeze and a history of asthma. Which stress agent is the most appropriate?

    1. AAminophylline before the test
    2. BAdenosine infusion
    3. CDipyridamole infusion
    4. DDobutamine infusion

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21. Question 21 · Medium

    A brain death perfusion study with Tc-99m HMPAO shows no tracer in the brain, while the scalp and nose show activity. What does this indicate?

    1. ARaised perfusion due to cerebral oedema
    2. BAbsent cerebral perfusion, supporting brain death
    3. CA study that cannot be read without contrast CT
    4. DNormal perfusion with poor labelling of the tracer

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22. Question 22 · Medium

    A Tc-99m pertechnetate scan shows a solitary nodule that takes up no activity, while the rest of the thyroid is normal. This 'cold' nodule should be:

    1. AReported as a hyperfunctioning nodule
    2. BIgnored, because a cold nodule is always benign
    3. CUltrasound, then consider fine-needle aspiration
    4. DTreated at once with I-131 therapy

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23. Question 23 · Medium

    A three-phase bone scan for suspected osteomyelitis of the foot is most consistent with infection when it shows:

    1. AIncreased activity in the delayed phase only at the site
    2. BIncreased activity in flow, blood pool and delayed phases at one site
    3. CIncreased activity in the flow phase only at the site
    4. DDecreased activity in all three phases at the site

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24. Question 24 · Medium

    A patient has received an oral I-131 therapy dose for Graves' disease and is going home. Which advice is most appropriate?

    1. AKeep distance from children and pregnant women, and flush twice
    2. BReturn to work in a nursery school the very next day
    3. CShare cutlery and towels freely, since I-131 is not excreted
    4. DSleep in the same bed as a partner for close comfort

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25. Question 25 · Easy

    Which agent is given by mouth for measuring thyroid uptake at 24 hours?

    1. AF-18 FDG glucose analogue
    2. BTl-201 chloride, a cardiac agent
    3. CI-123 sodium iodide
    4. DTc-99m MDP bone agent

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