Optimization of Alanine Measurements for Fast and Accurate Dosimetry in FLASH Radiation Therapy.

Optimization of Alanine Measurements for Fast and Accurate Dosimetry in FLASH Radiation Therapy. Radiat Res. 2020 May 20;: Authors: Gondré M, Jorge PG, Vozenin MC, Bourhis J, Bochud F, Bailat C, Moeckli R Abstract FLASH radiation therapy (FLASH-RT) reference dosimetry to obtain traceability, repeatability and stability of irradiations cannot be performed with conventional dosimetric methods, such as monitor chambers or ionization chambers. Until now, only passive dosimeters have provided the necessary dosimetric data. Alanine dosimetry is accurate; however, to be used for FLASH-RT in biological experiments and for clinical transfer to humans, the reading time needs to be reduced, while preserving a maximum deviation to the reference of ±2%. Optimization of alanine dosimetry was based on the acquisition of electron paramagnetic resonance (EPR) spectra with a Bruker spectrometer. Reading parameters such as the conversion time, the number of scans, the time constant, the microwave power and the modulation amplitude of the magnetic field were optimized as a trade-off between the signal-to-noise ratio (SNR) and the reading time of one measurement using the reference 10.1 Gy alanine pellet. After optimizing the parameters, we compared the doses measured with alanine pellets up to 100 Gy with the reference doses, and then determined the number of measurements necessary to get a difference lower than ±2%. A low-dose alanine pellet of 4.9 ...
Source: Radiation Research - Category: Physics Authors: Tags: Radiat Res Source Type: research