A systematic benchmark method for analysis and comparison of IMRT treatment planning algorithms

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Intensity-modulated radiation therapy (IMRT) systems are increasingly used, but their complexity poses challenges for dosimetrists and physicists.
• Numerous commercial IMRT systems exist, featuring distinct software and planning options that can be overwhelming for users.

Purpose of the Study:

• To develop and present tools and procedures for evaluating and comparing different intensity-modulated radiation therapy (IMRT) systems.
• To investigate the characteristics of IMRT algorithms and explore the influence of various parameters on dose distribution.

Main Methods:

• Utilizing geometric target volumes (TV) and critical normal tissues (CNT) within a simulated quality assurance phantom.
• Employing a half-donut (hemi-annulus) TV with a central cylinder CNT on a CT scan.
• Defining a dose-homogeneity index (DHI) as the ratio of the dose received by 90% of the volume to the minimum dose received by the hottest 10% of the volume.

Main Results:

• A systematic approach is suggested for varying IMRT parameters, starting with the number of intensity stratifications.
• The effects of priority and penalty settings on both the target volume and critical normal tissues were explored.
• The influence of the number of beams on dose distributions, DHI, subfield count, and monitor units was evaluated.

Conclusions:

• The proposed phantom geometry and DHI provide a robust method for characterizing IMRT algorithms.
• The study outlines a structured parameter exploration strategy to optimize IMRT treatment planning.
• These methods aid in understanding and comparing the performance of different IMRT systems.