SU-E-J-26: Automated Estimation Method of Patient Setup Errors Using Simulated Portal Images for Prostate Cancer...

Area of Science:

• Medical Physics
• Radiotherapy
• Image Analysis

Background:

• Accurate patient positioning is critical for effective radiotherapy.
• Setup errors can lead to under- or over-dosing of the target volume.
• Automated methods can improve the efficiency and accuracy of error detection.

Purpose of the Study:

• To develop and evaluate a novel automated method for estimating patient setup errors.
• To utilize simulated and real portal images for error detection in prostate cancer radiotherapy.

Main Methods:

• A template matching technique using cross-correlation and Sobel filters was employed.
• Simulated portal images were generated from CT data using X-ray attenuation principles.
• Digitally reconstructed radiography (DRR) and simulated portal images were used with localized pelvic templates for error estimation.

Main Results:

• The method achieved average residual errors of 0.79 mm (LR) and 3.17 mm (SI) for DRR images.
• For simulated portal images, average residual errors were 1.26 mm (LR) and 2.05 mm (SI).
• A combined approach using simulated and DRR images yielded an overall Euclidean distance error of 3.22 mm.

Conclusions:

• The developed automated method demonstrates potential for accurate patient setup error estimation in prostate cancer radiotherapy.
• This technique can contribute to enhanced treatment accuracy and patient safety.