SU-E-T-466: TCP and NTCP: Is That All?

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Physics

Background:

• Modern radiotherapy techniques like IMRT and VMAT offer improved tumor coverage but raise concerns about secondary cancer risks due to neutron and photon contamination.
• Balancing treatment benefits against risks of organ damage and secondary cancers is crucial for selecting optimal radiotherapy techniques.

Purpose of the Study:

• To develop a tool for estimating radiotherapy treatment success by incorporating neutron secondary cancer risk.
• To assess the impact of neutron peripheral dose on overall treatment outcomes.

Main Methods:

• A novel digital detector (DD) was developed for real-time assessment of neutron equivalent dose distribution in organs.
• A biological model was created integrating real-time neutron dose data with tumor control (TCP) and normal tissue complication (NTCP) probabilities derived from DVH.
• The model was applied to evaluate treatment success across various radiotherapy techniques (3DCRT, IMRT, VMAT, Helical Tomotherapy) at different energy levels.

Main Results:

• High-energy, MU-demanding techniques achieved the highest uncomplicated tumor control rates.
• Neutron peripheral dose risks are significant and comparable to established normal tissue complication probabilities (NTCPs), necessitating their inclusion in treatment assessment.

Conclusions:

• The developed methodology for online organ neutron peripheral dose assessment can be effectively integrated with biological models.
• This integration enables accurate prediction of treatment success, crucially accounting for secondary cancer risks in radiotherapy planning.