Red Shell: Defining a High-Risk Zone of Normal Tissue Damage in Stereotactic Body Radiation Therapy

Rather than defining tolerance and toxicity as simply a dose level received by the tissues, the volume of tissue receiving risk levels above tolerance can be quantified as the “cost” of SBRT. This concept may be adopted in other techniques offering ablative and high-dose gradients. Further consideration should be given to collecting clinical data for refining the choice of constraint doses, especially in parts of the brain, lung, liver, and kidney.