Radiopharmaceuticals for Cardiac Imaging

• Endothelial inflammation
• Plaque formation
• Flow limiting CA stenoiss
• Ischemia
• Ventricular dysfunction
• ECG abnormality
• Chest pain
• Infarctions

1. Tl 201 Thallous Chloride

2. Sestamibi<Cardiolite> (used for heart and breast img)

3. Tetrofosmin <Myoview>(used for heart img)

4. RBC's

1. Add Tc 04 to kit and heat in boiling water for 10 min

Tc04 + citrate ------> Tc Citrate

2.  Copper complex is broken; free MIBI ligands displace citrate forming Tc Sestamibi

**MIBI is an oily liquid that has to be compounded to coppper**

1. Add up to 240 mCi of Na99mTcO4 in 4-8 mL in kit.

2. Remove 2ml of N2 gas from vial to admit air.

3. Incubate 15min, use w/n 12 hrs.

*Hydrogen radical H+ and hydrated electron e- are reducing species.  Letting air into the vial allowes O2 to scavenge the reducing species*

*Tetrofosmin is mixed with gluconate to keep it soluble*

• 1.Rb 82
• 2. F18-FDG
• 3. N-13 Ammonia

• Active transport
• Redistribution
• -K+ analog, remains in heart longer than K+

• Blood flow markers:
• -Rb82
• -N13 Ammonia

• Viability:
• F18 FDG

• 1. High first pass extraction
• 2. Remain fixed in the heart long enough to image

• REST: .6-.8 mL/min/g
• STRESS: 3-4 mL/min/g

• 1. Short axis
• 2. Vertical long axis
• 3. Horizontal long axis

• Both are vasodilators
• Increase CA blood flow 4-5x

• *Adenosine directly stimulates CA receptors WHILE
• dipyridamole blocks adenosine re-uptake

**Caffiene BAD bc it blocks adenosine from reaching receptors...stop 12 hrs prior**

• 1. STRESS: Inject 3-4 mCi; DTST 15 min
• 2. WAIT 2.5-4 hr; take rest images

• PROBLEMS:
• Sensitivity is high but specificity is low

regadenosine:  BOLUS (inj given after)

dipyridamole:  4 min (inj given after)

adenosine: 6 min (inj given half way)

• 1. Extent: Large, med, or small
• 2. Severity: marked, moderate, mild, or questionable.
• 3. Reversibility:
•    Ischemia: completely reversible-partially reversible
•    Scar: permanent (not reversible)
• 4. Interpretation can be:
• -Qualitative, semi-quantitative, quantitative

• REVASCULARIZATION
• >10%

• 1. Less attenuation artifacts
• 2. Quantitative
• 3. High signal to noise ratio

• 1. Rest CT
• 2. Rest Study (40 mCi)
• 3. Stress Study (Regadenosine + 2nd inj)
• 4. Stress CT

• Has a higher 1st pass extraction flow compared to MIBI and Tl 201
• CAN DO exercise study

• 1. Assess ventricular wall motion abnormalities
• (Hypokenesis, akenesis, dyskenesis)
• 2. Assess systolic wall thickening
• 3. Measure EF and volumes

• 1. FIRST-PASS Angiogram Study
• -IV bolus TcO4
• evaluate R and L EF

• 2. ECG Gated Equilibrium Study (MUGA)
• -IV inj of RBC's, MIBI, Tetrofosmin
• -Assess L EF only!!

• 1. In Vivo
• -Inject Sn-PYP (Sn associates with hemoglobin, reducing the Tc and allowing it to tag to hemoglobin)
• -Wait 20 min
• -Inj 30 mCi of TcO4

• 2. Modified In Vivo Method
• -Inject PYP; wait 20 min
• -Remove 10mL blood w/ heparinized syringe containing 30 mCi of TcO4
• -Incubate 10 min; reinject pt.

 

= EF

Determine if revascularization would benefit the patient

SPECT : Tl201 Thallium Chloride (Rest/Redistribution Study)

PET: N13 or F18 FDG (Perfusion/ Metabolism Study)

• 1. High carb meal
• 2. Inject 25 mCi
• 3. Acquire CT image
• 4. Wait 4 min to allow blood clearance
• 5. Acquire PET images

**Follow with F-18 FDG Metabolism Study (make sure glucose is within range; inj 15 mCi)**