Evaluation of patient-specific motion management for radiotherapy planning computed tomography using a statistical...

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• Accurate radiotherapy requires precise tumor targeting, which can be challenged by organ motion.
• Lung stereotactic body radiotherapy (SBRT) and prostate volumetric modulated arc therapy (VMAT) are advanced radiation techniques sensitive to positional accuracy.

Purpose of the Study:

• To evaluate the probabilistic randomness of treatment predictions using computed tomography (CT) data.
• To assess the importance of patient-specific motion management in lung SBRT and prostate VMAT.

Main Methods:

• Analysis of 3D displacement errors in 4DCT for lung SBRT patients (n=30) comparing upper lobe (UG) vs. middle/lower lobe (LG) groups.
• Utilized Shewhart control charts to analyze 3D displacement errors between planning CT (MPCT) and cone-beam CT (CBCT) for prostate VMAT patients (n=24).

Main Results:

• Significant differences in 3D displacement errors were observed between UG and LG in lung SBRT, but no correlation with duty cycle.
• Prostate VMAT analysis showed >8 mm 3D displacement errors exceeding control limits on Shewhart charts.

Conclusions:

• Overall statistical data from planning CT indicate probabilistic randomness in predictions during lung SBRT and prostate VMAT.
• Patient-specific motion management is essential to improve treatment accuracy in these radiotherapy techniques.