Embodiments of the present disclosure provide improved techniques for dosimetry in radiotherapy treatment. In a fractionated radiotherapy treatment, once the first fraction is complete and has been verified, data is generated which is representative of the dose development during delivery of the treatment for that patient and that treatment plan. This data can be used as a comparator for the instantaneous doses observed during subsequent fractions, allowing real-time dosimetry verification for the second and subsequent fractions after a successful first fraction.
