Future oncology (London, England) 2013-06
Reirradiation with stereotactic body radiotherapy: analysis of human spinal cord tolerance using the generalized linear-quadratic model.
ABSTRACT
AIM
Using the generalized linear-quadratic (gLQ) model, we reanalyzed published dosimetric data from patients with radiation myelopathy (RM) after reirradiation with spinal stereotactic body radiotherapy (SBRT).
MATERIALS & METHODS
Based on a published study, the thecal sac dose of five RM patients and 14 no RM patients were reanalyzed using gLQ model. Maximum point doses (Pmax) in the thecal sac were obtained. The gLQ-based biological effective doses were calculated and normalized (nBEDgLQ) to a 2-Gy equivalent dose (nBEDgLQ = Gy2/2_gLQ). The initial conventional radiotherapy dose, converted to Gy2/2_gLQ, was added.
RESULTS
Total (conventional radiotherapy + SBRT) mean Pmax nBEDgLQ was lower in no RM than RM patients: 59.2 Gy2/2_gLQ (range: 37.5-101.9) versus 94.8 Gy2/2_gLQ (range: 70.2-133.4) (p = 0.0016). The proportion of total Pmax nBEDgLQ accounted for by the SBRT Pmax nBEDgLQ was higher for RM patients. No RMs were seen below a total spinal cord nBEDgLQ of 70 Gy2/2_gLQ.
CONCLUSION
The gLQ-derived spinal cord tolerance for total nBEDgLQ was 70 Gy2/2_gLQ.
Related Questions
In a patient who received full dose to the spinal cord 10+ years prior, would SBRT be appropriate salvage therapy or is hyperfractionation prefer...
New comment by Radiation Oncologist at Indiana University Health ( May 21, 2020)
To piggyback on this, does anyone know if this was published? I am interested in reviewing but have not been able to find this series.