“…Recommended dose constraints in spinal SRS are also conservative like the brain: 14 Gy/1 Fr (EQD2 2 = 56 Gy) to 0.03 cc (radius = 2 mm) of spinal cord, 10 Gy/1 Fr (EQD2 2 = 30 Gy) to absolute spinal cord volumes smaller than 0.35 cc (radius = 4 mm), and 10 Gy/1 Fr to no more than 10% of the partial spinal cord volume (5–6 mm above the target spine to 5–6 mm below the target spine). 178 , 179 ) In recent RCT protocols, the dose constraint to the spinal cord in high-precision 3DXT was 17 Gy/2 Fr (EQD2 2 = 44.6 Gy), which is biologically similar to the dose constraint of 44 Gy/22 Fr (EQD2 2 = 44 Gy) in conventional 2DXT. 180 ) However, using the same dose constraints to the spinal cord, high-precision 3DXT was able to give 24 Gy/2 Fr (EQD2 2 = 84 Gy, EQD2 10 = 44 Gy) to vertebral metastatic tumors improving the therapeutic radio for pain at 3 months compared with the 2DXT, 20 Gy/5 Fr (EQD2 2 = 43.8 Gy, EQD2 10 = 31.3 Gy).…”