Serial and Parallel Organs

  • Organs vary in their sensitivity not only to the amount of radiation dose they receive, but also to the distribution of that dose.
  • Organs may be divided into subunits. Each subunit may be functional or non-functional following radiation damage.
    • Subunits may be as small as cells or as large as lobes of the liver.
  • Serial Organs are organs in which disabling any subunit causes the entire organ to fail.
  • Parallel Organs are organs in which many or all of the subunits must be disabled to cause organ failure.
Serial OrgansParallel Organs
Spinal CordLungs
Brain StemLiver
Optic StructuresKidneys