We have successfully implemented online 4D dose reconstruction in our research treatment planning and delivery platform. The tracking solution can be used on a conventional linac. The tracking and delivery software DynaTrack runs on a computer in the linac control room, while the workstation running DynaPlan can be placed anywhere, as long as a lowlatency network connection is available. The algorithms for dose calculation and accumulation reach a high memory bandwidth of 50-70 GB/s on the workstation used in this study. Although the runtimes are reasonably stable, Windows is not a real-time operating system. Hence there might always be an unexpected lag, resulting in individual outlier runtimes for a few scattered instances. The mean computation time per MLC aperture ranged from 21.3 to 34.5 ms which was well below 40 ms. Hence, a computation rate of 25 Hz can be maintained. If latency builds up nonetheless, it can be compensated during beam-off periods, when no accumulation has to be performed. For the patient **data** in this study, the runtimes scale with the size of the dose-influence data. On computers with less memory bandwidth or computational power, the number of slices to calculate and accumulate dose for could be decreased (e.g., to the target region-of-interest only, instead of the whole lung volume).