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

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiological Health

Background:

• Radiotherapy accelerators, such as the Clinac 21EX, are sources of neutron radiation.
• Intensity-modulated radiation therapy (IMRT) is an advanced radiotherapy technique that delivers precise radiation doses.
• Understanding neutron dose equivalent in IMRT is crucial for patient and staff safety.

Purpose of the Study:

• To quantify neutron dose equivalent in IMRT compared to standard non-IMRT treatments.
• To investigate the relationship between neutron dose, patient dose, and machine workload.
• To establish recommendations for reporting neutron production in IMRT.

Main Methods:

• Experiments were performed on a Clinac 21EX radiotherapy accelerator.
• An IMRT treatment plan was utilized for dose measurements.
• Neutron dose equivalent was measured as a function of patient dose and machine workload.

Main Results:

• IMRT mode demonstrated a higher neutron dose intensity relative to patient dose compared to standard non-IMRT.
• When normalized to machine workload, measured neutron dose equivalents were found to be similar between IMRT and non-IMRT modes.
• This indicates that workload is a significant factor in neutron production.

Conclusions:

• Neutron production in IMRT is more dose-intensive per patient dose.
• Reporting neutron production relative to machine workload is recommended for IMRT treatment modes.
• This approach provides a more consistent comparison of neutron dose across different treatment techniques.