Fig. 3.

Illustration of dose accumulation at the position of the red cross in panel a. Panel b plots $d\left(\overrightarrow{x},t\right)$ as a function of t, showing that most of the dose accumulation is within a narrow window of time (blue rectangle). Panel A displays the PBS spots which contribute significant dose to $\overrightarrow{x}$ (magenta dots); most of the dose is delivered between 10.0 and 92.5 ms of the PBS field delivery. A graphical example of $T\left(\overrightarrow{x}\right)=t_1‐t_0$ and $d^{†}$ for the point in the PBS field is illustrated in panels a, c. [Color figure can be viewed at wileyonlinelibrary.com]