Treatment planning systems dosimetry auditing project in Portugal

Area of Science:

• Medical Physics
• Radiotherapy
• Radiation Oncology

Background:

• The Medical Physics Division of the Portuguese Physics Society (DFM_SPF) collaborated with the IAEA on a national radiotherapy audit.
• The audit focused on the optimal usage of treatment planning systems (TPS) in clinical practice.
• This initiative aimed to assess the national radiotherapy workflow and dose delivery accuracy.

Purpose of the Study:

• To evaluate the performance and consistency of treatment planning systems across Portuguese radiotherapy centers.
• To ensure the optimal utilization of radiotherapy treatment planning systems.
• To identify areas for improvement in radiotherapy planning and dose delivery.

Main Methods:

• A national audit project was conducted from September 2011 to April 2012, involving all 24 radiotherapy centers in Portugal.
• The audit simulated the entire external beam radiotherapy workflow, including image acquisition, treatment planning, and dose delivery.
• A thorax CIRS phantom was used with 8 planning test cases for photon beams, assessing 15 measuring points and 5 sum results across various clinical techniques in 3D Conformal Radiotherapy.

Main Results:

• A total of 50 photon beams (4-18 MV) were audited using 25 linear accelerators and 32 distinct calculation algorithms.
• A very good consistency was observed in the performance of identical algorithms across different centers and for each beam quality.
• The audit provided comprehensive data on the national status of TPS calculations and dose delivery.

Conclusions:

• The national status of treatment planning system calculations and dose delivery for 3D conformal radiotherapy is generally acceptable.
• No major causes for concern were identified regarding the current radiotherapy practices in Portugal.
• The project successfully strengthened cooperation between centers and professionals, fostering future national collaborations in medical physics.