[Measurement for Maximum Leaf Velocity Using Piecewise Linear Approximation under Constant Acceleration of Multileaf...

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Context:

• Accurate measurement of multileaf collimator (MLC) performance is essential for ensuring precise radiation delivery in dynamic treatments.
• Variations in MLC leaf velocity can impact dose accuracy and treatment efficacy.
• Monitoring MLC parameters over time is critical for quality assurance in radiotherapy.

Purpose:

• To propose and validate a novel method for determining the maximum leaf velocity (Vmax) of MLCs during dynamic irradiation.
• To establish a reliable technique for assessing MLC performance using log file data.
• To enable easy confirmation of Vmax stability over extended periods.

Summary:

• The study developed a method using log file data and piecewise linear approximation to calculate leaf velocity (v(t)) during dynamic MLC irradiation.
• Maximum leaf velocity (Vmax) was determined from the constant velocity segments of the fitted v(t) curve.
• Measurements over seven months demonstrated clear distinction of acceleration and velocity segments, yielding Vmax values with low standard deviations (<0.04 cm/s).

Impact:

• The proposed method provides an accessible tool for verifying the long-term stability of MLC Vmax.
• Consistent Vmax is crucial for maintaining the accuracy and safety of Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT).
• This technique supports quality assurance protocols, enhancing the reliability of radiation treatment delivery.