Neutron production associated with radiotherapy linear accelerators using intensity modulated radiation therapy mode.

A number of experiments were conducted on a Clinac 21EX radiotherapy accelerator using an IMRT treatment plan to determine neutron dose equivalent as a function of both patient dose delivered and machine workload. It was determined that IMRT mode is more neutron dose intensive as a function of patient dose when compared to a similar standard non-IMRT treatment. It was found that when the neutron production is normalized to workload, the measured neutron dose equivalents are similar. It is therefore recommended that neutron production be reported as a function of workload when considering IMRT treatment modes.