Tc-99m Sestamibi and tetrophosmin Flashcards
Passive Diffusion of sestamibi
Cytoplasmic mitochondria binding
1st pass cetraction of 60%
Fixed localization (minimal redistribution)
1-2% dose localization in myocardium
Myocardial retention: T1/2 = 6 hrs
Normal Biodistribution sestamibi
- Hepatobiliary
- -gall bladder
- colon (CO)
- bowel
- GU
- cardiac
Advantages sestamibi
Radionuclide characteristics
Improved resolution
Decreased imaging time
Fixed distribution
Delayed imaging
Passive diffusion tetrophosmin
Cytoplasmic mitochondrial binding
1st pass extraction of 50%
1-2% localization in myocardium
Myocardial retention: T1/2 = 4 hrs
Normal biodistribution tetrophosmin
- colon
- gb
- gu
advantages tetrophosmin
Less hepatic uptake
More rapid clearance from liver after exercise
RP reconstitution
parameters
SPECT +/- CT, 370 - 1110 MBq
128 matrix, 64 views, 180o – covers 45 RAO to 135 LPO
Usually use circular b/c elliptical can create artifacts, or use a
roving zoom
25-30 sec per view, dual-headed camera (half-time imaging
or resolution recovery)
1 day protocol
- Rest Dose
- 1 - 2 hrs Rest Images
- 1 - 4 hrs Stress Test/Inject
- 0.5 - 1.5 hrs Stress Images
protocol advantages and disadvatages
Department
Patient
Dose
Images
Two Day protocol
- Day One Stress
- Stress/inject
- 0.5 - 1.5 hrs Image
- Day Two Rest
- Inject 1 - 2 hrs images
Dual isotope
One day
Rest: 201Tl
Stress: 99mTc agent
Patient prep
NPO 4 hrs
No caffeine or nicotine for 12 - 24 hrs
1 Day Study
Light meal between rest & stress
Medications to discontinue
Stop Dypyridimole & Adenosine
Stop :
Theophylline - 3 Days
Aminophylline - 2 Days
Pentoxifylline - 1 Day
- Calcium Channel Blockers
(48 - 72 hrs
- Beta blockers (72 hrs)
- Long-acting nitrates (12hrs)
