Medical Physics — Imaging Modalities

digraph Imaging {
  rankdir=LR;
  node [shape=box, style=rounded];
  "X-ray" -> "Absorption of X-rays";
  "CT" -> "3-D from many X-rays";
  "MRI" -> "Proton spins in a field";
  "Ultrasound" -> "Reflected sound echoes";
  "PET" -> "Positron-emitting tracer";
}