I85PREP
⌘ K
AOBNM Nuclear Medicine study materials
AOBNM Nuclear Medicine study resources

AOBNM Nuclear Medicine practice questions

One question at a time. Build your AOBNM Nuclear Medicine understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Nuclear Medicine (general)

Which radiopharmaceutical is most commonly used for myocardial perfusion imaging at rest and with stress?

  1. Iodine-131 sodium iodide
  2. Gallium-67 citrate
  3. Technetium-99m sestamibi Correct answer.
  4. Technetium-99m sulfur colloid

Explanation

Tc-99m sestamibi (and tetrofosmin) are the standard perfusion tracers because they distribute with myocardial blood flow and are trapped in viable myocytes. I-131, Ga-67, and sulfur colloid have entirely different biodistributions.

Question 2Nuclear Medicine (general)

The radionuclide generator used to produce technetium-99m on site is based on the decay of which parent?

  1. Germanium-68
  2. Molybdenum-99 Correct answer.
  3. Strontium-82
  4. Tin-113

Explanation

A Mo-99/Tc-99m generator exploits the 66-hour Mo-99 parent, which decays to the 6-hour Tc-99m daughter that is eluted with saline. The other parents feed different generator systems.

Question 3Nuclear Medicine (general)

The physical half-life of fluorine-18 is closest to which value?

  1. 6 hours
  2. 2.7 days
  3. 13 hours
  4. 110 minutes Correct answer.

Explanation

F-18 has a physical half-life of about 110 minutes, which permits transport of FDG between sites but requires efficient scheduling. The other values correspond to Tc-99m, I-123, and Ga-67 respectively.

Question 4Nuclear Medicine (general)

Which agent is the standard radiopharmaceutical for bone scintigraphy?

  1. Iodine-123 metaiodobenzylguanidine
  2. Fluorine-18 sodium fluoride
  3. Technetium-99m methylene diphosphonate Correct answer.
  4. Technetium-99m DTPA

Explanation

Tc-99m MDP adsorbs to the hydroxyapatite crystal surface and accumulates where bone turnover is increased, making it the workhorse bone tracer. The other agents have renal, cardiac-adrenergic, or PET bone applications.

Question 5Nuclear Medicine (general)

A patient scheduled for an iodine-131 therapy should be counseled about which precaution related to body fluids?

  1. Saliva poses no radioactivity risk
  2. Sweat should be collected on absorbent pads for disposal
  3. Flush the toilet twice after use and wash hands thoroughly Correct answer.
  4. No special handling is needed for urine

Explanation

I-131 is excreted primarily in urine and saliva, so double flushing and hand hygiene reduce contamination of the household. Standard radiation safety guidance addresses these excretory routes.

Question 6Nuclear Medicine (general)

Which finding on a ventilation-perfusion scan is most consistent with a high probability of pulmonary embolism?

  1. Matched ventilation and perfusion defects
  2. Multiple segmental perfusion defects with normal ventilation Correct answer.
  3. Diffuse symmetric tracer uptake
  4. A single subsegmental matched defect

Explanation

Mismatched defects, where perfusion is reduced but ventilation is preserved in a segmental distribution, are the hallmark of PE. Matched defects usually reflect parenchymal lung disease rather than embolus.

Question 7Nuclear Medicine (general)

In a parathyroid scintigraphy protocol using a dual-phase sestamibi technique, a persistent focus of activity on the delayed image most likely represents which structure?

  1. Parathyroid adenoma Correct answer.
  2. Submandibular lymph node
  3. Thyroid adenoma
  4. Salivary gland

Explanation

Sestamibi washes out of normal thyroid tissue faster than from parathyroid adenomas, so a focus that persists on delayed imaging suggests parathyroid tissue. Thyroid and salivary tissue typically show faster washout.

Question 8Nuclear Medicine (general)

Which radiopharmaceutical is used for a gastric emptying study?

  1. Technetium-99m sulfur colloid in a solid meal Correct answer.
  2. Technetium-99m pertechnetate
  3. Gallium-67 citrate
  4. Indium-111 pentetreotide

Explanation

A solid or semi-solid meal labeled with Tc-99m sulfur colloid is followed over time to measure gastric emptying. The other agents do not label a meal for motility assessment.

Question 9Nuclear Medicine (general)

A patient with suspected acute cholecystitis undergoes hepatobiliary scintigraphy. Nonvisualization of the gallbladder at 4 hours with normal hepatic and biliary ductal activity most suggests which diagnosis?

  1. Hepatocellular failure
  2. Cystic duct obstruction consistent with acute cholecystitis Correct answer.
  3. Normal gallbladder filling
  4. Common bile duct obstruction

Explanation

If the gallbladder fails to fill while bile reaches the bowel, cystic duct obstruction is the leading explanation, supporting acute cholecystitis. Common duct obstruction would also impair bowel activity.

Question 10Nuclear Medicine (general)

Which tracer is used for sentinel lymph node mapping in breast cancer surgery?

  1. Fluorine-18 FDG
  2. Technetium-99m MAG3
  3. Technetium-99m sulfur colloid Correct answer.
  4. Iodine-123 sodium iodide

Explanation

Filtered Tc-99m sulfur colloid is injected near the tumor and migrates to the sentinel node, which is identified with a gamma probe. FDG, MAG3, and iodine have different clinical roles.

Question 11Nuclear Medicine (general)

Which radiopharmaceutical provides functional renal imaging based on tubular secretion?

  1. Technetium-99m MDP
  2. Technetium-99m DTPA
  3. Technetium-99m pertechnetate
  4. Technetium-99m MAG3 Correct answer.

Explanation

MAG3 is secreted by the proximal tubules and gives high renal-to-background ratios, making it useful for assessing tubular function and obstruction. DTPA is filtered by glomeruli rather than secreted.

Question 12Nuclear Medicine (general)

A Meckel diverticulum scan uses which radiopharmaceutical?

  1. Technetium-99m pertechnetate Correct answer.
  2. Indium-111 oxine
  3. Technetium-99m sulfur colloid
  4. Fluorine-18 FDG

Explanation

Pertechnetate is taken up by ectopic gastric mucosa, which is present in a bleeding Meckel diverticulum, allowing its detection. The other tracers do not localize to gastric mucosa.

Question 13Nuclear Medicine (general)

In FDG PET imaging, elevated uptake is expected physiologically in which structure?

  1. Pancreas
  2. Brain cortex Correct answer.
  3. Skeletal muscle at rest
  4. Liver

Explanation

The brain uses glucose avidly and shows intense physiologic FDG uptake, which is a normal finding. The pancreas, resting muscle, and liver show comparatively lower background uptake.

Question 14Nuclear Medicine (general)

Which patient preparation is required before an FDG PET scan to reduce physiologic myocardial and muscle uptake?

  1. Strenuous exercise immediately before scanning
  2. Consuming a high-carbohydrate meal
  3. Drinking a glucose solution
  4. Fasting for at least 4 to 6 hours Correct answer.

Explanation

Fasting lowers blood glucose and insulin, reducing competing uptake in myocardium and skeletal muscle and improving tumor-to-background contrast. Carbohydrate loading or exercise would increase those background signals.

Question 15Nuclear Medicine (general)

The radionuclide used for bone pain palliation via beta emission is which of the following?

  1. Technetium-99m MDP
  2. Strontium-89 chloride Correct answer.
  3. Gallium-68 DOTATATE
  4. Fluorine-18 sodium fluoride

Explanation

Sr-89 is a beta-emitting calcium analogue that localizes to osteoblastic metastases and delivers palliative radiation to bone. The other agents are diagnostic rather than therapeutic.

Question 16Nuclear Medicine (general)

A patient with suspected osteomyelitis in a region with prior hardware undergoes imaging. Which approach best distinguishes infection from sterile inflammation?

  1. Single-phase bone scan alone
  2. Plain radiography
  3. Ultrasound of the soft tissues
  4. Labeled leukocyte imaging combined with bone marrow imaging Correct answer.

Explanation

Combining labeled leukocyte imaging with bone marrow imaging improves specificity because marrow displacement without leukocyte accumulation indicates sterile inflammation, while concordant uptake suggests infection. A single bone scan lacks specificity in the setting of hardware or prior surgery.

Question 17Nuclear Medicine (general)

In a patient with a thyroid nodule, a technetium-99m pertechnetate scan shows a focus of uptake that suppresses the rest of the gland. What is the most appropriate next consideration?

  1. Confirmation of a cold nodule requiring biopsy
  2. Diagnosis of medullary thyroid carcinoma
  3. Immediate radioiodine ablation without further workup
  4. Evaluation for an autonomously functioning toxic nodule Correct answer.

Explanation

A hot nodule with suppression of the remaining gland indicates autonomous function, and the clinical question shifts to hyperthyroidism management rather than malignancy exclusion. Cold nodules, by contrast, carry a higher malignancy concern.

Question 18Nuclear Medicine (general)

Which physiologic factor most directly affects the distribution of a diffusible perfusion tracer in the lung?

  1. Alveolar macrophage density
  2. Bronchial mucous gland activity
  3. Regional pulmonary blood flow Correct answer.
  4. Lymphatic clearance rate

Explanation

Perfusion tracers distribute according to regional pulmonary blood flow, so areas of reduced flow appear as defects. Macrophage density, mucous glands, and lymphatic clearance do not govern tracer distribution.

Question 19Nuclear Medicine (general)

Which statement correctly describes the relationship between absorbed dose and administered activity in radionuclide therapy?

  1. Absorbed dose is independent of administered activity
  2. Absorbed dose decreases as retention time lengthens
  3. Absorbed dose depends only on photon energy
  4. Absorbed dose generally increases with administered activity and retention time Correct answer.

Explanation

In radionuclide therapy, the absorbed dose to a target depends on the cumulative activity (administered activity integrated over retention time) and the absorbed fraction. Longer retention or higher activity increases the dose.

Question 20Nuclear Medicine (general)

Which quality control test is performed on a dose calibrator to verify accuracy?

  1. Measuring background counts in a well counter
  2. Assaying a known reference source and comparing to the expected activity Correct answer.
  3. Checking the collimator for scratches
  4. Performing a chi-square test on a gamma camera

Explanation

Accuracy of a dose calibrator is verified by measuring a standardized source and comparing the result with its known activity within an accepted tolerance. The other tests address different instruments or parameters.

Question 21Nuclear Medicine (general)

The photopeak in a gamma camera spectrum corresponds to which phenomenon?

  1. Compton scatter within the patient
  2. Total absorption of the gamma photon within the detector Correct answer.
  3. Pair production in the collimator
  4. Characteristic x-ray emission from the crystal

Explanation

The photopeak represents full-energy deposition from a gamma photon interacting in the crystal, producing a signal proportional to the incident energy. Scatter events deposit only part of the energy and form the Compton continuum.

Question 22Nuclear Medicine (general)

Which collimator is most appropriate for imaging a high-energy radionuclide such as iodine-131?

  1. High-energy parallel-hole collimator Correct answer.
  2. Low-energy high-resolution collimator
  3. Converging collimator
  4. Pinhole collimator

Explanation

High-energy collimators have thicker septa to prevent penetration by the higher-energy photons of I-131. Low-energy collimators would suffer septal penetration and degraded image quality.

Question 23Nuclear Medicine (general)

Which radiopharmaceutical is used to assess cardiac sympathetic innervation?

  1. Technetium-99m sestamibi
  2. Iodine-123 metaiodobenzylguanidine Correct answer.
  3. Fluorine-18 FDG
  4. Technetium-99m MAA

Explanation

I-123 MIBG is a norepinephrine analogue taken up by sympathetic nerve terminals, allowing assessment of cardiac innervation. Sestamibi reflects perfusion, FDG reflects metabolism, and MAA is trapped in pulmonary capillaries.

Question 24Nuclear Medicine (general)

What is the primary purpose of administering potassium iodide before iodine-131 therapy for thyroid cancer?

  1. To block thyroid uptake of free radioiodine and reduce unwanted exposure Correct answer.
  2. To increase tumor uptake of radioiodine
  3. To shorten the physical half-life of I-131
  4. To improve renal clearance of the tracer

Explanation

Blocking agents saturate the thyroid so any free radioiodine is not taken up by normal thyroid tissue, protecting it from unnecessary dose. They do not increase tumor uptake or alter the physical half-life.

Question 25Nuclear Medicine (general)

A lymphoscintigraphy study for melanoma uses a filtered particulate tracer. Which property makes it suitable for identifying the sentinel node?

  1. Rapid renal excretion localizes the node
  2. High beta emission permits external detection
  3. Long physical half-life allows delayed imaging days later
  4. Particle size allows migration and retention in the first draining node Correct answer.

Explanation

Particle size is optimized so the tracer travels through lymphatics and is trapped in the first draining node, which is identified as the sentinel node. Beta emission is not used for external detection and renal clearance does not localize nodes.

Question 26Nuclear Medicine (general)

Which radiopharmaceutical is most commonly used for myocardial perfusion imaging at rest and stress?

  1. Iodine-123 metaiodobenzylguanidine
  2. Technetium-99m sestamibi Correct answer.
  3. Fluorine-18 FDG
  4. Gallium-67 citrate

Explanation

Technetium-99m sestamibi is a lipophilic cation that is taken up by myocardial cells in proportion to regional blood flow, making it the workhorse tracer for rest-stress myocardial perfusion imaging. Its favorable half-life and imaging characteristics allow high-quality SPECT.

Question 27Nuclear Medicine (general)

In a standard whole-body FDG PET/CT protocol, approximately how long should a patient fast before the study?

  1. No fasting is required
  2. At least 4 to 6 hours Correct answer.
  3. At least 30 minutes
  4. At least 12 hours

Explanation

Fasting for at least 4 to 6 hours lowers serum insulin and glucose levels, reducing physiologic uptake in skeletal muscle and myocardium so that FDG accumulates preferentially in tissues with high glycolytic activity. This improves lesion contrast and diagnostic accuracy.

Question 28Nuclear Medicine (general)

Which radiopharmaceutical is used for a hepatobiliary scan to evaluate acute cholecystitis?

  1. Technetium-99m DTPA
  2. Technetium-99m sulfur colloid
  3. Technetium-99m pertechnetate
  4. Technetium-99m mebrofenin Correct answer.

Explanation

Technetium-99m mebrofenin is an iminodiacetic acid derivative that is extracted by hepatocytes and excreted into the biliary tree, allowing functional assessment of the gallbladder and biliary system. Nonvisualization of the gallbladder supports the diagnosis of acute cholecystitis.

Question 29Nuclear Medicine (general)

Which radiopharmaceutical is used for a ventilation study in a V/Q lung scan?

  1. Xenon-133 gas
  2. Technetium-99m macroaggregated albumin
  3. Technetium-99m DTPA aerosol Correct answer.
  4. Technetium-99m sulfur colloid

Explanation

Technetium-99m DTPA aerosol is inhaled and distributes throughout the airways and alveoli, providing a ventilation image that can be compared with perfusion. It is commonly used because it allows same-day imaging with technetium-99m.

Question 30Nuclear Medicine (general)

Which radiopharmaceutical is used for a bone scan?

  1. Gallium-67 citrate
  2. Fluorine-18 sodium fluoride
  3. Technetium-99m methylene diphosphonate Correct answer.
  4. Technetium-99m pertechnetate

Explanation

Technetium-99m methylene diphosphonate (MDP) adsorbs to the hydroxyapatite crystal of bone, with increased uptake in areas of osteoblastic activity. It is the standard agent for planar and SPECT bone scintigraphy.

Question 31Nuclear Medicine (general)

Which radiopharmaceutical is used for a renal scan to assess tubular secretion?

  1. Technetium-99m dimercaptosuccinic acid
  2. Technetium-99m gluceptate
  3. Technetium-99m mercaptoacetyltriglycine Correct answer.
  4. Technetium-99m pertechnetate

Explanation

Technetium-99m mercaptoacetyltriglycine (MAG3) is actively secreted by the renal tubules and provides high-quality images of renal perfusion and function. It is the preferred agent for evaluating renal function, especially in patients with impaired renal function.

Question 32Nuclear Medicine (general)

Which radiopharmaceutical is used for sentinel lymph node biopsy in breast cancer?

  1. Technetium-99m MDP
  2. Technetium-99m sestamibi
  3. Technetium-99m pertechnetate
  4. Technetium-99m sulfur colloid Correct answer.

Explanation

Technetium-99m sulfur colloid particles are injected near the tumor and are taken up by macrophages in the sentinel lymph node, allowing intraoperative identification. Particle size is optimized for lymphatic migration and nodal retention.

Question 33Nuclear Medicine (general)

Which radiopharmaceutical is used for a parathyroid scan?

  1. Technetium-99m pertechnetate
  2. Technetium-99m sestamibi Correct answer.
  3. Iodine-123 sodium iodide
  4. Technetium-99m MDP

Explanation

Technetium-99m sestamibi accumulates in both thyroid and parathyroid tissue, but it washes out of normal thyroid more rapidly than from hyperfunctioning parathyroid adenomas. This differential washout allows identification of parathyroid adenomas on delayed images.

Question 34Nuclear Medicine (general)

A patient with suspected osteomyelitis in a region with prior hardware undergoes imaging. Which approach best distinguishes infection from hardware-related inflammation?

  1. Gallium-67 citrate imaging alone
  2. Three-phase bone scintigraphy alone
  3. FDG PET/CT alone
  4. Combined labeled leukocyte and bone marrow imaging Correct answer.

Explanation

Labeled leukocyte imaging combined with bone marrow imaging improves specificity because infection shows leukocyte uptake without marrow uptake, whereas hardware inflammation may show concordant uptake on both. This dual-study approach helps differentiate infection from sterile inflammation.

Question 35Nuclear Medicine (general)

In a patient with a thyroid nodule, a technetium-99m pertechnetate scan shows a focus of uptake that suppresses the rest of the gland. What is the most likely diagnosis?

  1. Papillary thyroid carcinoma
  2. Hashimoto thyroiditis
  3. Thyroid cyst
  4. Autonomous functioning thyroid nodule Correct answer.

Explanation

A hyperfunctioning nodule takes up pertechnetate avidly and suppresses TSH, reducing uptake in the remainder of the gland. This pattern is characteristic of an autonomous functioning nodule, which is usually benign.

Question 36Nuclear Medicine (general)

A patient with suspected acute cholecystitis undergoes hepatobiliary scintigraphy. Nonvisualization of the gallbladder at 4 hours after tracer injection is most consistent with which diagnosis?

  1. Normal gallbladder function
  2. Chronic cholecystitis
  3. Acute cholecystitis Correct answer.
  4. Common bile duct obstruction

Explanation

Nonvisualization of the gallbladder beyond 4 hours in the appropriate clinical setting is highly suggestive of acute cholecystitis, because the inflamed cystic duct obstructs bile flow into the gallbladder. A normal study would show gallbladder activity within 60 minutes.

Question 37Nuclear Medicine (general)

Which radiopharmaceutical is used for a Meckel diverticulum scan?

  1. Technetium-99m pertechnetate Correct answer.
  2. Technetium-99m MDP
  3. Technetium-99m sulfur colloid
  4. Technetium-99m DTPA

Explanation

Technetium-99m pertechnetate is taken up by ectopic gastric mucosa, which is present in many symptomatic Meckel diverticula. This allows noninvasive detection of the diverticulum.

Question 38Nuclear Medicine (general)

Which radionuclide is used for bone pain palliation via beta emission?

  1. Technetium-99m MDP
  2. Iodine-131 sodium iodide
  3. Strontium-89 chloride Correct answer.
  4. Gallium-67 citrate

Explanation

Strontium-89 is a beta-emitting calcium analog that localizes to osteoblastic metastases and delivers palliative radiation to bone lesions. It is used for pain relief in patients with widespread osseous metastases.

Question 39Nuclear Medicine (general)

A patient with prior hardware in the femur has suspected osteomyelitis. Which imaging approach best distinguishes infection from hardware-related inflammation?

  1. Gallium-67 citrate imaging alone
  2. FDG PET/CT alone
  3. Combined labeled leukocyte and bone marrow imaging Correct answer.
  4. Three-phase bone scintigraphy alone

Explanation

Labeled leukocyte imaging combined with bone marrow imaging improves specificity because infection shows leukocyte uptake without marrow uptake, whereas hardware inflammation may show concordant uptake on both. This dual-study approach helps differentiate infection from sterile inflammation.

Question 40Nuclear Medicine (general)

Which factor most strongly determines the spatial resolution of a gamma camera image?

  1. Photomultiplier tube gain
  2. Energy window width
  3. Collimator hole size and septal thickness Correct answer.
  4. Pulse height analyzer threshold

Explanation

In a gamma camera, the collimator is the primary determinant of spatial resolution because it defines the geometric acceptance of gamma rays. Smaller holes and appropriate septal thickness improve resolution at the cost of sensitivity.

Question 41Nuclear Medicine (general)

Which property of technetium-99m makes it particularly well suited for gamma camera imaging?

  1. Its 140 keV gamma emission is optimal for the NaI(Tl) detector Correct answer.
  2. It has a long physical half-life of 60 days
  3. It emits high-energy positrons that produce coincidence photons
  4. It is a pure alpha emitter with high linear energy transfer

Explanation

Technetium-99m decays by isomeric transition to emit a 140 keV gamma ray, which is near the optimal energy for detection by a sodium iodide crystal with acceptable collimation and minimal septal penetration. Its short 6-hour half-life and generator availability further support clinical use.

Question 42Nuclear Medicine (general)

Which detector material is most commonly used in the gamma camera to convert gamma rays into light photons?

  1. Bismuth germanate scintillator
  2. Cesium iodide crystal
  3. Thallium-activated sodium iodide crystal Correct answer.
  4. High-purity germanium semiconductor

Explanation

Thallium-activated sodium iodide (NaI(Tl)) is the standard scintillation material in gamma cameras because of its high light output and good energy resolution at typical imaging energies. Other scintillators are used in different applications but are not the mainstay for planar and SPECT gamma cameras.

Question 43Nuclear Medicine (general)

Which quality control test for a gamma camera assesses the uniformity of the detector response across the entire field of view?

  1. Spatial linearity phantom test
  2. Flood field uniformity test Correct answer.
  3. Energy peak calibration test
  4. Center-of-rotation alignment test

Explanation

A flood field uniformity test uses a uniform source to evaluate count rate variations across the detector, identifying photomultiplier tube or crystal nonuniformities. It is typically performed daily for gamma cameras.

Question 44Nuclear Medicine (general)

Which radiopharmaceutical is most commonly used for first-pass radionuclide ventriculography to evaluate left ventricular function?

  1. Technetium-99m DTPA Correct answer.
  2. Technetium-99m macroaggregated albumin
  3. Technetium-99m sestamibi
  4. Technetium-99m sulfur colloid

Explanation

Technetium-99m DTPA is a small molecule that remains in the vascular space during the first pass through the heart, allowing assessment of ventricular function. It is also used for renal imaging and glomerular filtration rate measurement.

Question 45Nuclear Medicine (general)

Which radiopharmaceutical is used for a gastrointestinal bleeding study to detect active hemorrhage?

  1. Technetium-99m labeled red blood cells Correct answer.
  2. Technetium-99m pertechnetate
  3. Technetium-99m sulfur colloid
  4. Technetium-99m mebrofenin

Explanation

Technetium-99m labeled red blood cells remain in the vascular space and are used to detect active gastrointestinal bleeding, which appears as a focal area of increasing activity over time. The labeled red cell method allows imaging for up to 24 hours.

Question 46Nuclear Medicine (general)

Which radiopharmaceutical is used for cisternography to evaluate cerebrospinal fluid flow?

  1. Technetium-99m DTPA
  2. Indium-111 DTPA Correct answer.
  3. Iodine-123 ioflupane
  4. Technetium-99m HMPAO

Explanation

Indium-111 DTPA is injected intrathecally for cisternography because its longer half-life allows imaging over 24 to 48 hours as the tracer moves through the cerebrospinal fluid spaces. Technetium-99m agents are also used but indium-111 is common for delayed imaging.

Question 47Nuclear Medicine (general)

Which radiopharmaceutical is used for lymphoscintigraphy to map lymphatic drainage in breast cancer?

  1. Technetium-99m MDP
  2. Technetium-99m sestamibi
  3. Technetium-99m pertechnetate
  4. Technetium-99m sulfur colloid Correct answer.

Explanation

Technetium-99m sulfur colloid particles are too large to pass through capillary membranes and are cleared by the lymphatic system, allowing sentinel lymph node mapping. The tracer is injected near the tumor or biopsy site.

Question 48Nuclear Medicine (general)

Which radiopharmaceutical is used for a somatostatin receptor scintigraphy study to detect neuroendocrine tumors?

  1. Indium-111 pentetreotide Correct answer.
  2. Iodine-123 MIBG
  3. Fluorine-18 FDG
  4. Technetium-99m octreotide

Explanation

Indium-111 pentetreotide binds to somatostatin receptors and is used for imaging neuroendocrine tumors that express these receptors. It is the prototypical somatostatin receptor scintigraphy agent.

Question 49Nuclear Medicine (general)

Which radiopharmaceutical is used for a brain perfusion SPECT study?

  1. Technetium-99m sulfur colloid
  2. Technetium-99m HMPAO Correct answer.
  3. Technetium-99m MDP
  4. Technetium-99m DTPA

Explanation

Technetium-99m HMPAO is a lipophilic agent that crosses the blood-brain barrier and is retained in brain tissue in proportion to regional cerebral blood flow. It is used for brain perfusion SPECT, including evaluation of epilepsy and dementia.

Question 50Nuclear Medicine (general)

Which radiopharmaceutical is used for a testicular scan to evaluate for torsion?

  1. Technetium-99m pertechnetate Correct answer.
  2. Technetium-99m DTPA
  3. Technetium-99m MDP
  4. Technetium-99m sulfur colloid

Explanation

Technetium-99m pertechnetate is used for testicular scintigraphy because it is a small ion that remains in the vascular space, allowing assessment of testicular blood flow. Decreased perfusion suggests torsion, while increased perfusion suggests inflammation.