Radiobiological considerations of re-irradiation tolerance of the spinal cord

Abstract

Re-irradiation tolerance of the spinal cord depends upon the volume of the spinal cord irradiated, the total dose, the dose per fractional, the elapsed time between the treatments and the region of the spinal cord involved. Clinical data on the retreatment tolerance of the spinal cord are sparse and inconclusive. Radiobiological laboratory evidence has indicated the presence of long term recovery of the spinal cord damage. Fractionation sensitivity during reirradiation is comparable with the first session of radiation treatment. After an initial dose of 45 Gy, 50% recovery has been reported by Schultheiss and Stephens for an elapsed period of two years for re-irradiation considerations.