Card Set Information

2013-03-06 17:15:54

Kowalski's lung lecture
Show Answers:

  1. What are the 2 main group of lung pharmaceutical agents?
    • 1. Perfusion (labeled particles)
    • -Tc 99m Macroaggregated Albumin (MAA)

    • 2. Ventilation Agents (gases and aerosols)
    • -Xenon 133 (gas)
    • - Tc 99m DTPA (aerosol)
  2. How does the perfusion scan work?
    1: MAA (20-60 microns) is trapped in smaller sized lung capillaries arterioles

    • 2: PE causes regions of absent radioactivity 
    • NORMAL: no perfusion defects (hot)
    • ABNORMAL: obstructed perfusion (cold), ventilation confirms this
  3. List some biological properties of MAA
    • 1. Particle clearance by fragmentation
    • 2. T 1/2 depends on size of particle and hardness (how hot temp is when making particles)
    • 3. Cleared particles are phagocytosed in RES with proteolytic digestion in Kupffer's cell.
  4. What is the relationship between time, MAA particles and activity?
    • Increases                             Decreases
    • Time                                    Activity
    • #of MAA Particles
  5. How big are MAA particles and how many are typically given to adult patients?
    • MAA
    • size: 20-60 microns (too small, it goes to liver)
    • # of particles:300,000 (3mCi)

    * Dilute if suspected pulmonary hypertension*
  6. What's the purpose of Lung Ventilation Imaging
    • 1. Assess lung ventilation
    • 2. Differentiate PE from COPD
  7. What are the 3 phases of Vent study?
    • Wash-In: (inhales Xe 133 10mCi)
    • Equilibrium: pt re-breathes gas/O2 mixture (5min after inhalation)
    • Wash-Out: Pt inhales air, Xe-133 exhaled
  8. What does COPD and PE look like on vent and perf images?
    •                  Vent                 Perf
    • COPD      Defect               Defect

    Pe           Normal              Defect
  9. What 2 ways does MAA enter systemic circulation?
    1. After fragmentation in lung (no risk)

    • 2. Via right-to left cardiac shunt (VSD- ventricular septal defect)
    • -MAA bypassed lungs and ends up in kidney/brain.

    *Max pt dose of 1mg MAA particles*