Nuclear Medicine Clinic Flashcards
Aim for HIDA scan
Hepatobiliary - evaluate biliary system: liver, gall-bladder, bile duct
Cause of Neonatal Jaundice
More Bilirubin -> liver still not fully work -> can’t fully eliminate -> store bilirubin
What is Billirubin
Yellowish pigment that is made during the breakdown of RBC
What is Biliary atresia
Disease : Bile ducts are blocked, leading to bile buildup in the liver and causing liver damage
Symptom of Biliary atresia
- Cholestatic jaundice
- acholic stools: dark urine, pale stool - lack bile duct in GI
- hepatomegaly
Bile route
[R, L] hepatic duct -> Common hepatic duct -> [Common bile duct, Cystic duct - gallbladder] -> pancreatic duct -> Duodenum
Radiopharm for HIDA scan
Tc-99m DISIDA (diisopropyl) or name as disofenin(hapatolite)
Why use Tc-99m DISIDA in pediatric
superior uptake and rapid clearance [ low dose ]
Dose of Tc-99m DISIDA
from Bilirubin(mg/dl) to mCi/kg (min) : 2-10mg/dl -> 0.15(0.5)mCi/kg
Patient Prepare for HIDA scan
- NPO 2-4hrs if age > 6month
- No Ba study 48hrs
- In newborn use Phenobarbital(medication) to enhance flow of bile
Aim for HIDA scan in infant(<6month)
Different BA vs NH
- evaluate biliary atresia(no uptake) or neonatal hepatitis(delay, ALT AST high)
workflow HIDA scan
On IV Tc-99m DISIDA - take image for 1hrs -> inject CCK -> take image again after 30mins
How DISIDA show in bile duct
DISIDA : mimics the behavior of bile acids
; go to Hepatocyte(active transport) -> bile duct route
What is CCK
Cholecystokinin : induces the gallbladder to contract and
release bile into the small intestine
Normal uptake Tc-99m DISIDA
- 5 mins: liver
- 30 mins: gallbladder
- 1hrs: small bowels
Abnormal uptake Tc-99m DISIDA
- no uptake (gallbladder, bowel) : acute cholecystitis
- show in bowel before gallbladder: chronic
- in pediatric : abnormal or obstruction - biliary atresia
Risk factor of DVT
- age > 60, cancer, catheter insertion
- genetic - hypercoagulability
- immobilize, obesity, pregnancy
- hormone replacement therapy
cause of Thrombus(virchow’s triad)
- stasis blood flow
- endothelial injury
- hypercoagulability
cause ; Stasis blood flow
- postoperative
- paralysis
- long travel
cause ; Endothelial injury
Antithrombotic cytokines (NO, PGl2) lower from smoking, surgery, V catheters
cause ; Hypercoagulability
more Procoagulants
- malignancy, lung CA, pregnancy
- factor 5 leiden mutation
less Anticoagulants
- nephrotic syndrome
- Antiphospholipic syndrome
Diagnostic tools for DVT
- doppler US
- CTV and MRV
- D-dimers lab
- contrast venography
- RNV (Radionuclide venography)
DVT ; Pretest probability (Well’s score)
score 3 is high proba for DVT
- every clinical is +1 score
- but alternative diag likely DVT -2
What if high D-dimer
a sign of a blood clotting disorder
Approach after well’s score
- score > 2 -> US/RNV
- else -> D-dimer if <0.5 mg/L not DVT else go to US/RNV
Radiopharm for RNV(DVT scan)
Tc-99m MAA
Activity for Tc-99m MAA (RNV)
10-15mCi dilute 15-20cc saline (dorsal vein both feet)
workflow for RNV(DVT scan)
- tourniquet on both ankle
- inject Tc-99m MAA
- take image
- tourniquet off
- take image
Image protocol for DVT scan (Whole body)
- scan from Toe to apex lung (16 cm/min)
- both detector (H mode)
Image protocol for DVT scan (spot)
- preset count 1200 kcts
- AP chest, LAO-RPO chest, both LAT chest
Why use tourniquet for DVT scan
- control Tc-99 MAA to deep vein not superficial vein
- then remove to see is it obstruct