IMRT 2018

Proposal Of Human Spinal Cord Re-irradiation

▪ Accumulated dose was calculated using the Biological Effective Dose with a/b of 2 Gy and 4 Gy ▪ The cumulative doses ranged from 108 to 205 Gy (median dose, 135 Gy) ▪ Myelopathy was seen only in patients who had received one course to a dose of >102 Gy (n = 9) or were retreated after 2 months (n = 2). ▪ In the absence of these two risk factors, no myelopathy developed in 19 patients treated with <135.5 Gy or 7 patients treated with 136-150 Gy

0% risk of myelopathy if Cumulative dose <70-75Gy (EQD2/2) One course <50Gy (EQD2/2) Interval >6 months

Nieder C, Grosu AL, Andratschke NH, Molls M. Proposal of human spinal cord reirradiation dose based on collection of data from 40 patients. Int J Radiat Oncol Biol Phys. 2005 Mar 1;61(3):851-5.