2017_SBRT_Course Book
Safety of spine SBRT: myelopathy
OAR definition
Dose in patients with radiation myelopathy Conclusion
Study # events
Ryu 2006
SC 6mm CC of TV
1 / 177
9.6Gy to 10%
10% < 10Gy
Gibbs 2009
6 / 1075
NS
D max
8.5 – 26.2Gy
1cm 3 < 8Gy
D max below thresholds using LQ model
Sahgal 2010
5 / 24 case control study
Thecal sack
D max
median 59Gy (nBED 2/2 )
• (Very) Few patients developed radiation induced myelopathy • Dose – response inconclusive • However: follow-up short in majority of patients
ESTRO SBRT 2017 - Matthias Guckenberger
07.09.17
15
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Safety of spine SBRT: myelopathy Multi-institutional analysis: • 9 cases with radiation induced myelopathy • 66 cases w/o radiation induced myelopathy Sahgal IJROBP 2012 1 fraction 3 fractions 5 fractions 1%probability 9.2 14.8 18.2 2%probability 10.7 17.4 21.5 3%probability 11.5 18.8 23.1 4%probability 12 19.6 24.4 5%probability 12.4 20.3 25.3 • Doses converted to 2Gy equivalent dose (EQD2/2) • Dmax to thecal sack • LARGE confidence intervals
ESTRO SBRT 2017 - Matthias Guckenberger
07.09.17
16
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