Dose-response curves for MRI-detected radiation-induced temporal lobe reactions in patients after proton and carbon ion therapy: Does the same RBE-weighted dose lead to the same biological effect?

作者：Gillmann Clarissa; Lomax Antony J; Weber Damien C; Jaekel Oliver; Karger Christian P^*

来源：Radiotherapy and Oncology, 2018, 128(1): 109-114.

DOI：10.1016/j.radonc.2018.01.018

• Proton and carbon ion radiotherapy
• Relative biological effectiveness
• Local effect model
• Temporal lobe tolerance dose

Purpose: To derive the dose-response curve for temporal lobe reactions (TLRs) after proton therapy and to compare the resulting relative biological effectiveness (RBE)-weighted tolerance doses based on an RBE of 1.1 with published values for carbon ions, which were calculated by the two versions of the local effect model (LEM I or IV).
Methods and materials: 62 patients treated with protons for skull base tumors were analyzed for TLRs using magnetic resonance imaging. Within the mean follow-up time of 38 months, TLRs were observed in six patients. Dose-response curves based on the RBE-weighted maximum dose, excluding the 1 cm(3) - volume with the highest dose, were derived and compared to previously published dose-response curves for carbon ions, which were obtained using LEM I or IV, respectively.
Results: The dose-response curves for protons and LEM I were found to be almost identical while the curve of LEM IV was shifted toward higher doses. The resulting tolerance doses at the 5% effect level were 68.2(+2)(-5) 68.6(+3.0)(-3.9) and 78.3(+3)(-5) Gy (RBE), respectively.
Conclusions: The RBE-weighted dose prescription for protons leads to the same RBE-weighted dose-response curve for TLR as the one for LEM I-based carbon ions, while LEM IV predicts clinically significant higher tolerance doses.

• 出版日期2018-7