Scan protocol optimisation : kV

• Generally standardised at around 120 kV

• Lower kV : 80 / 100 can be used

  • Higher dose for same image noise
  • Better contrast than at 120kV
    • Iodine – soft tissue contrast is better, so may be optimal for some angiographic head exams
  • Can be used in paediatric protocols to reduce beam intensity

• Higher kV : 135 / 140 sometimes used

  • Marginally lower dose for same image noise
  • Contrast is slightly poorer
  • Penetration is greater
    • Can be used for obese patients or dense body sections