Nuclear Medicine Clinic Flashcards

1
Q

Aim for HIDA scan

A

Hepatobiliary - evaluate biliary system: liver, gall-bladder, bile duct

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2
Q

Cause of Neonatal Jaundice

A

More Bilirubin -> liver still not fully work -> can’t fully eliminate -> store bilirubin

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3
Q

What is Billirubin

A

Yellowish pigment that is made during the breakdown of RBC

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4
Q

What is Biliary atresia

A

Disease : Bile ducts are blocked, leading to bile buildup in the liver and causing liver damage

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5
Q

Symptom of Biliary atresia

A
  1. Cholestatic jaundice
  2. acholic stools: dark urine, pale stool - lack bile duct in GI
  3. hepatomegaly
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5
Q

Bile route

A

[R, L] hepatic duct -> Common hepatic duct -> [Common bile duct, Cystic duct - gallbladder] -> pancreatic duct -> Duodenum

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6
Q

Radiopharm for HIDA scan

A

Tc-99m DISIDA (diisopropyl) or name as disofenin(hapatolite)

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7
Q

Why use Tc-99m DISIDA in pediatric

A

superior uptake and rapid clearance [ low dose ]

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8
Q

Dose of Tc-99m DISIDA

A

from Bilirubin(mg/dl) to mCi/kg (min) : 2-10mg/dl -> 0.15(0.5)mCi/kg

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9
Q

Patient Prepare for HIDA scan

A
  • NPO 2-4hrs if age > 6month
  • No Ba study 48hrs
  • In newborn use Phenobarbital(medication) to enhance flow of bile
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10
Q

Aim for HIDA scan in infant(<6month)

A

Different BA vs NH
- evaluate biliary atresia(no uptake) or neonatal hepatitis(delay, ALT AST high)

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11
Q

workflow HIDA scan

A

On IV Tc-99m DISIDA - take image for 1hrs -> inject CCK -> take image again after 30mins

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12
Q

How DISIDA show in bile duct

A

DISIDA : mimics the behavior of bile acids
; go to Hepatocyte(active transport) -> bile duct route

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13
Q

What is CCK

A

Cholecystokinin : induces the gallbladder to contract and
release bile into the small intestine

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14
Q

Normal uptake Tc-99m DISIDA

A
  • 5 mins: liver
  • 30 mins: gallbladder
  • 1hrs: small bowels
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15
Q

Abnormal uptake Tc-99m DISIDA

A
  • no uptake (gallbladder, bowel) : acute cholecystitis
  • show in bowel before gallbladder: chronic
  • in pediatric : abnormal or obstruction - biliary atresia
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16
Q

Risk factor of DVT

A
  • age > 60, cancer, catheter insertion
  • genetic - hypercoagulability
  • immobilize, obesity, pregnancy
  • hormone replacement therapy
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17
Q

cause of Thrombus(virchow’s triad)

A
  • stasis blood flow
  • endothelial injury
  • hypercoagulability
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18
Q

cause ; Stasis blood flow

A
  • postoperative
  • paralysis
  • long travel
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19
Q

cause ; Endothelial injury

A

Antithrombotic cytokines (NO, PGl2) lower from smoking, surgery, V catheters

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20
Q

cause ; Hypercoagulability

A

more Procoagulants
- malignancy, lung CA, pregnancy
- factor 5 leiden mutation

less Anticoagulants
- nephrotic syndrome
- Antiphospholipic syndrome

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21
Q

Diagnostic tools for DVT

A
  • doppler US
  • CTV and MRV
  • D-dimers lab
  • contrast venography
  • RNV (Radionuclide venography)
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22
Q

DVT ; Pretest probability (Well’s score)

A

score 3 is high proba for DVT
- every clinical is +1 score
- but alternative diag likely DVT -2

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23
Q

What if high D-dimer

A

a sign of a blood clotting disorder

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24
Q

Approach after well’s score

A
  • score > 2 -> US/RNV
  • else -> D-dimer if <0.5 mg/L not DVT else go to US/RNV
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25
Q

Radiopharm for RNV(DVT scan)

A

Tc-99m MAA

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26
Q

Activity for Tc-99m MAA (RNV)

A

10-15mCi dilute 15-20cc saline (dorsal vein both feet)

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27
Q

workflow for RNV(DVT scan)

A
  • tourniquet on both ankle
  • inject Tc-99m MAA
  • take image
  • tourniquet off
  • take image
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28
Q

Image protocol for DVT scan (Whole body)

A
  • scan from Toe to apex lung (16 cm/min)
  • both detector (H mode)
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29
Q

Image protocol for DVT scan (spot)

A
  • preset count 1200 kcts
  • AP chest, LAO-RPO chest, both LAT chest
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30
Q

Why use tourniquet for DVT scan

A
  • control Tc-99 MAA to deep vein not superficial vein
  • then remove to see is it obstruct
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31
Q

Normal RNV

A
  • single channel of deep vein from calf to distal IVC
  • symmetric
32
Q

Abnormal RNV

A
  • interrupt flow
  • presence superficial venous collaterals
33
Q

What is Lymphedema

A
  • store of lymph in between the skin and muscle
  • in extremity and sex organ
34
Q

Primary cause of Lymphedema

A
  • unknow, hereditary
  • Aplasia: incomplete development
  • Hypoplasia (75%), Hyperplasia (15%)
35
Q

Secondary cause of Lymphedema

A
  • filariasis
  • primary or metastatic neoplasm
  • lymph node dissection
  • RT, Chemo, severe infection
36
Q

Aim for lymphatic scan

A

find cause of edema (is from lymphatic obstruction)

37
Q

What is collateral lymph

A

auxiliary lymphatic pathway that forms when the primary lymphatic vessels are obstructed or damaged.

37
Q

what is Dermal backflow

A

reverse flow of lymphatic
fluid into the skin

38
Q

Radiopharm for Lymphatic scan

A

Tc-99m Dextran (nanocolloid) 1mCi (subcutaneous between both side thumb and index)

38
Q

work flow lymphatic scan

A

5, 15, 30, 45, 1hr, 4hrs

39
Q

Whole body protocol lymphatic scan

A
  • Lower : toe to spleen
  • Upper : hand to mid-chest
  • 1detector 12cm/min
40
Q

Spot protocol lymphatic scan

A
  • preset time 5mins
  • lower: leg, femur, pelvis
  • upper: both arm and chest
41
Q

What is PE

A

pulmonary embolism (PE) is a blood clot from leg(DVT) to lung artery

42
Q

How to tell it positive (PE)

A

unmatched (defect in perfusion) because it obstruct in artery and normal in air.

43
Q

Sign of PE

A
  • Tachypnea (res > 16/min)
  • Tachycardia (100 bpm)
  • gallop
  • temp > 37.8c
  • phlebitis (inflame vein)
  • edema, cyanosis
43
Q

Examination for PE

A
  • Chest x-ray
  • Pulmonary CTA
  • V/Q scan (ventilation - perfusion)
44
Q

V/Q scan indication

A
  • normal CXR
  • stable patient
  • pregnancy, children
45
Q

CTA indication (V/Q scan)

A
  • abnormal CXR
  • unstable patient
  • suspect massive PE
46
Q

Aim for V/Q scan

A
  • determine likelihood(proba) of PE
  • quantify before surgery lung CA
  • AV fistulae
  • confirm bronchopleural fistula
  • cause pulmonary hypertension
  • pre-treatment lung shunt fraction before 90Y-microshere
47
Q

V/Q scan image protocol

A

A-P, LAO-PRO, RAO-LPO, Both LAT
+ SPECT/CT

47
Q

Radiopharm for V/Q scan

A

Ventilation : 20mCi
- radioactive gas : Xe-133
- aerosols : DTPA, Phytate
- technegas : Tc-99m carbon

Perfusion : Tc-99m MAA (5mCi)

48
Q

Image protocol of V/Q scan

A

A-P, LAO-RPO, RAO-LPO, both chest LAT
+ SPECT/CT

48
Q

Interpretation of PE

A

Modified PIOPED II criteria (4 categories)
- normal
- high proba (PPV > 85%)
- very low proba (PPV < 10%)
- non-dx

49
Q

Aim for GI bleeding scan

A

Use Tc-99m RBC for estimate rate of blood loss, location

49
Q

Lower GI start from

A

colon

50
Q

Common cause of Lower GI bleeding

A

diverticular disease, angiodysplasia, diverticulosis

50
Q

Most common part of GI bledding

A

Upper GI (80%)

51
Q

Why use Tc-99m RBC than Sulfur colloid

A

half-life, sensitivity, accuracy

51
Q

benefit of Tc-99m RBC in vitro

A

re-inject IV improve heart-to-bkg ratio

52
Q

Radiopharm for GI bleeding

A

Tc-99m RBC(20mCi) or phytate (1mCi)

53
Q

normal distribution for Tc-99m RBC

A

heart, liver, spleen, penis, vessels

54
Q

Tc-99m RBC in vivo method

A
  1. stannous ion IV
  2. Tc-99m pertechnetate IV 20-30mins later
  • 75% labelling, fast and simple
  • unbound pertechnetate degrade quality
55
Q

Tc-99m RBC in vitro method

A
  1. Stannous ion IV then 20-30mins draw back to stannous chloride
  2. sodium hypochlorite added and remove with sequestering agent
  3. Tc-99m pertechnetate added
  • 97% labelling
  • costly
56
Q

GI bleeding image protocol

A
  • angiographic phase
  • dynamic image
  • static image
57
Q

Dynamic imaging (Tc-99m RBC)

A
  • 1 frame per 60s in 10-15mins
  • frame rate longer - lower temporal resolution - inaccurate localize
  • if rapid bowel need faster frame rate 1f per 10-20s
  • minimum 60mins if no bleeding detect and take after 24hrs
57
Q

Angiographic phase (Tc-99m RBC)

A
  • after inject : rate 1-3s for 60s
  • visualize vascular to differentiate blood pool and bleeding
57
Q

Static image (Tc-99m RBC)

A
  • head and neck (thyroid, salivary) to evaluate free pertechnetate
  • lateral pelvis to differentiate Tc-99m RBC in bladder(free pertechnetate) or rectum
58
Q

Processing of Tc-99m RBC

A

comparable every frame (subtracted)

59
Q

Lymphatic organ

A

bone marrow
thymus
lymph node
spleen
tonsils

60
Q

High bleeding finding Tc-99m RBC

A

early detection, intense activity, longer duration

60
Q

Internal dose of Tc-99m RBC

A

spleen(2.2 rads/20mCi) > heart > testes (minimum)

60
Q

Other cause of high Tc-99m RBC activity

A
  • renal activity from unexpected locations like pelvic or ectopic kidneys
  • movement of urine (after urinary diversion surgery)
  • vascular cause : aneurysms, fistula
  • splenosis : enlarge and inflame spleen
61
Q

benefit of NM in GI bleeding

A
  • detect as low as 0.1 mL/m rate
  • detect intermittent bleed
  • low dose than 3-phase CTA
  • no prepare needed
62
Q
A
63
Q
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64
Q
A
65
Q
A