bone scans - bennett

Question 1

Technetium-99

Answer 1

• rapid osteoblastic mediated chemical absorption on the surface of hydroxy appetite
  
  • BONE TURNOVER (senstivie, but not specific)
• physical half life = 6hrs
• 3 phase diagnostic study
  
  • 1st phase = dyamic or blood flow phase (3 secs)
  • 2nd phase = blood pool phase or tissue phase (3mins)
  • 3rd phase = delayed imaging phase (static) or bone imaging (3 hours)
    
    • localized to bone

Question 2

Gallium - 67 citrate

Answer 2

• Diagnostic tracer used for neoplasms; inflammatory disorders
• less dependent on blood flow
• MECH:
  
  • leukocyte localization, lactoferrina nd tarnsferrin binding and sideropohores of bacteria, bacterial uptake by phagocytes
• Slower rate of excretion
• Imaging performed:
  
  • 6-24 hours post injection for INFECTION
  • 24-72 hours post injection for NEOPLASMS

Question 3

Indium 111

Answer 3

• Oxine labeled white blood cells (INFECTIOUS PROCESSES)
• Binds to the cytoplasmic component of WBC cell membrane
• Dependent on chemotaxis of leukocytes

Question 4

Ceretec

Answer 4

• Tc 99 labelled WBC’s (HMPAO)
• INCREASED specificity for infectious processes