Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MBBS IV - Supplementary Courses > Diagnostic radiology - Nuclear Medicine > Flashcards

Diagnostic radiology - Nuclear Medicine Flashcards

1
Q

Most common radionucleotide?

A

Technetium-99m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Function of radionucleotide imaging?

A

Use radioactive isotopes-emitted ionizing radiation to assess organ function and structure

Detect changes in metabolism, blood flow, regional chemical composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Difference between Gamma radiation and X-ray

A

Gamma rays have higher energy and penetrating power than X-ray

X-ray = photons emitted from electron orbits
Gamma rays = photons emitted from nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain how a gamma camera works

A

1) Decay of radioisotopes (e.g. technetium-99m) releases ionizing radiation
2) Passage/ absorption of Tc99m photon in collimator
3) Scintillation in crystal emits light photons
4) Light photons interact with photocathode and is amplified in photoamplifier tube
5) Conversion into electrical signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

2 Cardiovascular nuclear imaging tests

A

Heart wall motion (MUGA scan)

Myocardial perfusion and viability scan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Indication for Multigated acquition scan (MUGA) for heart wall motion

A

Use Tc-99m tagged RBC

  • Ischemic heart disease - assess global LV function, regional wall motion and prognosis
  • Non-ischemic cardiomyopathy = assess LV function
  • Prior and after heart transplant
  • Chemo follow-up (e.g. cardiotoxic drugs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Classify regional wall motion seen on MUGA scans?

A

Hypokinesia
Akinesia
Dyskinesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Myocardial perfusion and viability scan.

  • Indications?
  • Radionucleotides
A

Coronary artery disease**

  • Myocardial infarction
  • Myocardial viability, perfusion under exercise or drug stress
  • Cardiac wall motion
  • Treatment of CAD
  • Preoperative risk assessment for sever myocardial ischemia or infarction

Thallium 201, Tc99m Sestamibi**

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe one stress test for myocardial perfusion and viability scan

List 4 drugs for cardiac stress
Which one to use for asthma

A

Vasodilation by Adenosine&raquo_space; dilate coronary vessels, stenotic vessels show ‘cold spots’

a2- agonist:

  • Dipyridamole
  • Adenosine
  • Regadenoson
B2 agoinst (for asthma)
- Dobutamine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Clinical indications for thyroid radionucleotide scan

A
  • D/dx Hyperthyroidism
  • Thyroid cancer
  • Thyroid nodules
  • Ectopic thyroid
  • Congenital hypothyroidism
  • Developmental defect: Lingual thyroid, Hemi-agenesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Compare treatment for Thyroiditis, Grave’s, Solitary toxic nodule and Toxic multinodular goiter

A

Thyroiditis: Beta-blocker, steroid

Grave’s: Antithyroid drugs, surgery, 5-15mCi I-131

Solitary toxic nodule: Surgery, 15-30mCi I-131

Toxic multinodular goiter = surgery, 60mCi I-131

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Thyroid CA metastasis. Type of radionucleotide scan needed?

A

Whole body I-131 scan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

3 primary causes of hyperparathyroidism?

Secondary cases?

A

Primary:
Solitary adenoma
Multiglandular parathyroid disease
Parathyroid carcinoma

Secondary to chronic renal failure, GI malabsorption, rickets, drugs

Secondary to hypocalcemia > parathyroid hyperplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Parathyroid localization

  • 3 non-invasive methods
  • 4 invasive methods
A

Non-invasive

  • US (neck)
  • CT/MRI (mediastinum)
  • Scintigraphy: planar, pinhole, SPECT/ SPECT-CT

Invasive:

  • Image-guided biopsy/ aspiration
  • Parathyroid angiography
  • Parathyroid venous sampling
  • Intra-operative US
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Radionucleotide for parathyroid scan?

Mechanism?

A

Tc-99m Sestamibi (same and Myocardial perfusion scan)

Retained by Oxyphil cells (mitochondria-rich)
Early phase: traces taken up by thyroid and parathyroid
Delayed phase: Tracer washout from thyroid and leave parathyroid stain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Indication for respiratory radionucleotide scans?

2 radionucleotides?

A

Acute pulmonary embolism/ Chronic PE

Compares ventilation and perfusion

Perfusion = Tc-99m MAA (Macroaggregated albumin)
Ventilation = Technegas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

CT Angiography or VQ scan.

Advantages and disadvantages?

A

CT angiography:
- Faster, better resolution
- Acute PE, no need for patient cooperation
C/O pregnant, CA breast, Renal failure

VQ scan:

  • Lower radiation exposure
  • Safe for pregnant, young women
  • High sensitivity, comparable to CTA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

3 radionucleotide scans for the GI tract

A
  1. In-vitro RBC labelling (UltraTag) for GI bleeding
  2. Tc-99m RBC scintigraphy for fresh melena
  3. Merkel’s scan and scintigraphy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

3 advantages of In-vitro RBC labelling (UltraTag) for GI bleeding over angiography

A
  • Can detect lower bleed rate/ insidious bleeding
  • Can detect intermittent bleeding up to 24 hours
  • Less invasive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Merkel’s scan
Indication?
Mechanism?
Patient preparation?

A

Children with lower GI bleeding

Tc-99m Pertechnetate is secreted by tubular glands of gastric mucosa

Prep: give H2 blocker to enhance Tc-99m Per technetate uptake and inhibit gastric mucosa release before scan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Name of radionucleotide scan to evaluate biliary tree?

Indications?

A

EHIDA scan

  • Evaluate congenital abnormalities of biliary tree: biliary atresia, choledochal cyst…etc
  • Acute and chronic cholecystitis
  • Detect bile leak
  • Evaluate gallbladder function
22
Q

Name of radionucleotide for EHIDA scan?

Mechanism?

A

Iminodiacetic acid (IDA)

Tc-99m IDA complex - Mebrofenin, Disofenin

IDA bound to albumin, extracted by hepatocyte, release into bile canaliculi
Structurally similar to bilirubin,. but no conjugation

23
Q

Neonate with persistent cholestatic jaundice with conjugated bilirubin 10x.
Cannot see gallbladder and bile ducts after 24h of EHIDA scan
Dx?

A

Biliary atresia

24
Q

Patient prep for EHIDA scan

A

Phenobarbitone for 5 days

> induce hepatic enzymes and increase secretion

25
Q

Indication for radionucleotide scan of MSS?

A
  • Bone metastasis
  • Primary bone tumor assessment
  • Dx Osteomyelitis
  • Unexplained bone pain
  • Assess metabolic bone diseases
26
Q

Describe structure and adsorption of radionucleotides used for bone scans

A

Tc-99m Phosphate analogs: Methylene Diphosphonate

Structural analog to calcium and hydroxyl group of phosphates

Adsorbed into bone surface, affected by osteoblast activity, Vascularity and sympathetic nerve supply

27
Q

Indication for Superscan (Beautiful Bone Scan)?

A

CA breast, CA prostate metastasis
Paget’s bone disease (localized to pelvis)

Benign:

  • Renal osteodystrophy
  • Secondary hyperparathyroidism
  • Osteomalacia
28
Q

Indication for radionucleotide scan of Genito-urinary system?

A

Kidney:

  • Cortical imaging
  • Outflow obstruction
  • Transplant
  • Vascular hypertension
  • Vesicoureteric reflux
29
Q

3 radiopharmaceuticals for genito-urinary scans?

What do they assess?

A

DMSA - Renal cortical binding
MAG3 - Tubular secretion
DTPA - Glomerular filtration

30
Q

Pyelonephritis, renal scarring, renal infarct: which type of radionucleotide scan?

A

DMSA - Renal cortical binding

31
Q

Describe GA-67 radionucleotide scan used for infection assessment.
Binding?

A

GA-67 citrate
similar to ferric ion

  • Bind to lactoferrin in lymphocytes and polymorphs
  • Bind to siderophores in Bacteria
  • Bind to transferrin and transferrin receptor CD71 > leak through vascular epithelium at site of infection
32
Q

Clinical indications for GA-67 citrate scan

A

Osteomyelitis
Pulmonary infection
Tuberculosis

Fever of unknown origin
Fever in immunocompromised

Autoimmune disorder
Drug induced pulmon1ary toxicity

33
Q

Normal distribution of GA-67 citrate in body? (what organs uptake)

A

Glandular tissue: breast, lacrimal, salivary…etc

Liver, GIT, Spleen

Bone marrow, soft tissue

Thymus in children

34
Q

Osteomyelitis is shown on GA-67 citrate scan. Next scan for assessment?

A

3 phase bone scan - assess lesion vascularity
1 - Dynamic flow study
2 - Blood pool image
3- Delayed static image

35
Q

List 2 radionucleotide scans for infections

A

GA-67 citrate scan

White blood cell scan (IN-111 Oxine)

36
Q

Describe the White blood cell scan (In-111 Oxine) for infections

A

Indium-111 oxine

  • Lipophilic, diffuses through leukocyte membrane, oxine diffuses out of cell and Indium stays in cytoplaslm

t1/2 = 67h

37
Q

Normal distribution of In-111 Oxine?

A

Liver
Spleen
Bone marrow

38
Q

2 radionucleotide scans for brain imaging?

Purpose of these tests?

A

Tc-99m HMPAO (Exametaxine)
Tc-99m ECD (Bicisate)

Cognitive impairment - scan whilst questioning with MMSE
Epilepsy
Brain death

39
Q

What must be excluded before Dx of brain death by radionucleotide imaging?

A

Exclude causes of coma

  • Primary hypothermia
  • Hypoglycemia
  • Electrolyte imbalance
  • Barbiturate overdose
  • Alcohol overdose
  • Sedative overdose
40
Q

Pheochromocytoma, Neuroblastoma, Decarboxylation cell line tumors (paraganglioma, medullary thyroid tumor)

Which radionucleotide test to use?

A

MIBG scan
MetaIdodoBenzylGaunidine
Analog of Norepinephrine

41
Q

Normal distribution of MIBG?

A 
Liver 
Spleen 
Myocardium 
Salivary glands 
Adrenals 
Thyroid

Others: nasal mucosa, bladder, colon

42
Q

Etiologies of pheochromocytoma.

Radionucleotide scan?

A

Sporadic 90%

Familial 10%

  • MEN IIa and IIb
  • Von Hippel Lindau syndrome
  • Neurofibromatosis type 1
  • Familial paraganglioma syndrome

MIBG scan

43
Q

Radionucleotides used for breast cancer lymphatic spread?

Difference between the types?

A

Tc-99m sulphur colloid/ nanocolloid/ antimony trisulfide

Difference in particle size:
Large particles = slower clearance from interstitial space and slower accumulation in sentinel LN
Small particles = easily enter lymphatic capillary and enter second tier nodes

44
Q

Radionucleotide for embolization?
Indication?
MoA?

A

Yttrium-90 glass or resin microspheres (TARE)

Palliative treatment for HCC and liver metastasis

Travel through arteries, deposit in tumor plexus/ periphery for embolization

45
Q

PET principle

A

PET radioisotope decays and emits positron and annihilates a nearby electron

> > cause emission of 2 gamma rays travelling in opposite directions

46
Q

Name one radiotracer used to scan for tumor on PET-CT

MoA

A

F-18 FDG

Competes with GLUT-1 receptor on cell membrane, GLUT-1 highly expressed on cancer cells

47
Q

Limitation of PET- CT using radiotracers to assess tumor activity?

A

TB can mimic malignancy

48
Q

Use of PET-MRI

Limitations

A

Head and neck cancer
Prostate cancer
Breast imaging
Paediatric cancers

Longer scan duration than PET-CT
No implants or pacemaker with ferrous metals

49
Q

Compare PET-CT with PET- MRI

  • Soft tissue contrast
  • Radiation exposure
A
  • Soft tissue contrast
    PET-MRI is better
  • Radiation exposure
    PET-CT is lower
50
Q

Compare PET-CT with PET- MRI

  • Attenuation correction
A
  • Attenuation correction
    PET-CT is validated
    PET-MRI is not validated
51
Q

Compare PET-CT with PET- MRI

  • Functional or Anatomical information
  • Time for scan
A
  • Functional or Anatomical information
    PET- CT = Anatomical/ morphological information
    PET-MRI = functional information
  • Time for scan
    PET-CT is much faster

MBBS IV - Supplementary Courses (54 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions