Table 1.

Reportable parameters for UHDR electron and proton beam deliveries

Parameters	Definition	Electron	Cyclotron	Synchrocyclotron	Synchrotron
Beam Energy		Nominal energy	Delivered energies at nozzle	Delivered energies at nozzle	Delivered energies at nozzle
Pulse repetition rate	Number of pulses per second	<400 Hz	near 100MHz	<1000 Hz	<1 Hz for spill
Duty cycle	Ratio of pulse ON time to OFF time	1/2000 – 1/100	quasicontinuous	<10%	2- tens of ms per pill
Temporal pulse structure	Temporal sequence of pulses from the beginning to end of delivery, including the intervals between fields	To resolve individual pulses and pulse-shaped structures	To resolve per spot delivery time structure if PBS	To resolve beam pulses in addition to spot delivery time structure if PBS	To resolve spill duration and intervals, in addition to spot delivery time structure if PBS
Beam intensity	Number of particles irradiated	Per beam, can be replaced by the beam dose	Per beam and per spot if PBS	Per beam, per pulse and per spot if PBS	Per beam, per spill and per spot if PBS
Cumulative dose per delivery	$D$ in Fig. 1a at userdefined reference point(s)
Dose per pulse	$D_p$ in Fig. 1a at userdefined reference point(s)	Per beam pulse	Per spot if PBS	Per beam pulse in addition to per spot if PBS	Per spot if PBS
Instantaneous dose rate	${\dot{D}}_p$ in Fig. 1a at userdefined reference point(s)	10^4 – 10^6 Gy/sec	${\dot{D}}_p$ within a spot duration if PBS	${\dot{D}}_p$ within a spot duration if PBS	${\dot{D}}_p$ within a spot duration if PBS
Mean dose rate per beam	$\overline{\dot{D}}$ in Fig. 1a for each beam at userdefined reference point(s)	40 – 3000 Gy/sec	Delivery specific spot pattern if PBS	Delivery specific spot pattern if PBS	Delivery specific spot pattern if PBS
Mean dose rate per fraction	$\overline{\dot{D}}$ in Fig. 1a for each fraction at userdefined reference point(s)	Delivery specific fields	Delivery specific fields	Delivery specific fields	Delivery specific fields
Volumetric dose rate distribution per beam and per fraction	Temporal dose distribution at each voxel in the treatment volume	Derived via beam modelling and monitoring data	Derived via beam modelling and monitoring data	Derived via beam modelling and monitoring data	Derived via beam modelling and monitoring data