Table 2.

Simulation time and time improvement with FastEPID.

	Conventional simulation	FastEPID simulation	FastEPID simulation on CPU cluster
Open field (${10}^8$ primary photons)	1412 CPU hours	10 CPU hours	No test
Las Vegas phantom (1 MU)	$1.383\times {10}^6$ CPU hours	$1.540\times {10}^4$ CPU hours	8 h
Pelvis phantom (1 MU)	No test	$5.095\times {10}^4$ CPU hours	30 h