Radiation myelopathy: a radiobiological review

Abstract

Purpose

In radiotherapy the risk of radiation myelopathy is radiobiologically considerable. This review aims to outline future radiobiological research to get closer to the mechanism of radiation myelopathy.

Methods

Different regimes and techniques of irradiation that deliver doses to the spinal cord lead to the development of radiation myelopathy. Up to now, interpretations of injuries have been based entirely on morphological observations and histological analysis.

Results

Using paralysis as the endpoint, large fraction size data were consistent with the linear quadratic model (α/β=2.41 Gy). Small fraction size data gave a much smaller value of α/β (0.48 Gy).

Conclusion

A possible explanation is the interaction of two different groups of target cells with different fractionation sensitivities and, therefore, different α/β values. This duality suggests that spinal cord vascular endothelial changes, both in the morphology and secretory profile, may convey information in addition to the definition of various cells that participate in the evolution of radiation myelopathy.