What radiation dose constraints should be used for the spinal cord in pediatrics?  

Should they be context/disease specific? 

Should use of chemotherapy before/after, or during radiotherapy modify these tolerances?

Contexts: extramedullary vs. intradural extramedullary vs. intramedullary tumors

Diseases: low vs. high grade primary solid tumor/sarcoma or low vs. high grade primary cns tumors

Chemotherapy: are there agents which are considered high risk for myelopathy when combined with radiotherapy.