Abdominal Imaging

• 1. Hepatocytes(polygonal cells)
• -85%
• -Metabolic functional cells (membrane transport)

• 2.Sinusoidal Cells
• -Endothelial cells
• -Kupffer's cells (phagocytic)

• Particulate = morphological
• Hepatobiliary = Functional

Gold, I-131, In-113 (produced in a tin generator)

• VIAL A
• 1. Source of sulfur
• 2. Gelatin - Prevents overswelling (puts - charge around particles so they repel each other)
• 3. EDTA - Chelates Al+ (prevents excess Al reacts w/ phosphate which will cause a lung scan)

• VIAL B
• Acid (lowers pH)

• VIAL C
• Buffer (inc pH to 6)

80% of SC are .4-.6 um

• 5 mCi
• 85% liver; spleen 5%; bone 10%
• Localized via phagocytosis by Kupffer cells

• Old: I-131 Rose Bengal
• Current: Tc 99m iminodiacetic acid analogs

• Yes:
• 1st FX: Drug portion (affects biologic distribution)
• 2nd FX: Chelate portion (binds Tc **necessary for organ localization**)

• 1. Anionic, fat loving, high extraction
• 2. Active transport
• 3. Compete w/ bilirubin uptake
• Lidofenin the least, Mebrofenin and Disofenin the most
• 4. ^ bilirubin=v liver uptake=^ kidney excretion
• 5. Critical Organ: large intestine

• Normal liver: 5-10 min
• "  GB: 10-20 min

• GB seen w/n 4 hr is CHRONIC cholecystitis
• "   seen w/n after 4 hr ACUTE

No SB activity = OBSTRUCTION

• .04 mg/kg over 3 min
• contracts sphincter of Oddi for GB visualization
• CHRONIC: GB shows
• ACUTE: GB NO show after 30 min

• 5mg/kg/day given 5 days prior
• enzyme inducer ^ bilirubin conjugation and excretion
• used to differentiate b/n biliary atresia and hepatitis
• HEPATITIS: bowel excretion occurs
• BILIARY ATRESIA: no bowel

• .02 ug/kg over 60 min (too fast will cause pt to vomit)
• PRE-CCK to reduce false positives
• POST CCK to measure EF (<38% is abnormal)

• Old RBC's are destroyed in the spleen
• Radiolabeled RBC's look like old RBC's which is good for spleen imaging

*Size of RBC is 7.5 um*

Seperate plasma so you only have tinned RBC so that TC take place of tin and labels RBC.**Sodium hypochloride gets rid of extra tin in vial**

Heating for more than 15 min=^ destruction= ^ liver uptake=BAD

• fragile cell membrane on RBC'S cause them to burst as they squeeze thu the 3 um sized fenestrae in the spleen sinusoids
• phagocytosis occurs
• 1 mCi
• DTST 30 MIN
• 70% uptake in spleen

• Pros of SC:
• Fast blood clearance
• High target to bkgd

• Pros of RBC:
• Best for intermittent bleed (this makes it agent of choice since GI bleeds are INTERMITTENT)

• 20 mCi in vitro method
• 5min img/1 hr; 24 hr image delay
• Active bleeding:
• -^ accumulation a@ site
• -translocation of activity