Purpose: To develop a method to select optimal combinations of PRF, PW and N based on current pre-measured machine characteristics in order to achieve the requested dose and the dose rate with IntraOp Mobetron for FLASH dose delivery.
Methods: We have developed a mixed integer optimization based computer program in MATLAB to evaluate the various irradiation geometries and find the optimum combination of operating parameters in order to best provide a prescribed dose and dose rate (DR). At FLASH DRs, this machine can only be programmed to deliver an integer number of pulses (N) with a set pulse repetition frequency (PRF) and pulse width (PW). Many different irradiation geometries are possible utilizing 3 different cones and various cone sizes. The cone and cone size used to shape the beam and SSD determines the dose per pulse (Dpp). The optimization code minimizes a function of dose and DRs for a given beam energy, cone size and irradiation geometry. When the exact dose and DR cannot be achieved, optimization proposes PRF, PW, N, and SSD resulting in the closest dose and the DRs.
Results: The developed optimization allows for optimal combinations of PRF, PW and N based on current pre-measured machine characteristics in order to achieve the requested dose and DR; hence eliminating the creation, use and updates of big spreadsheets to cover all PRF, PW, N, cone size, and geometry combinations and increases efficiency when planning for irradiation of large number of samples.
Conclusion: We have developed a code that selects the optimum combination of PRF, PW, and N parameters in order to achieve the requested dose and the dose rate, thus increasing efficiency when planning for the irradiation of a large number of samples.