Simulation of Cone Beam CT System Based on Monte Carlo Method

TL;DR

This paper develops and validates a Monte Carlo-based simulation model of a Cone Beam CT system to enhance image quality and dose assessment in adaptive radiation therapy.

Contribution

A novel Monte Carlo simulation model of the CBCT system was established and validated against measurements, improving dose verification in ART.

Findings

Calculated PDD within 1% accuracy up to 10cm depth

Over 85% of lateral dose points within 2% of measurements

Model aids in improving CBCT image quality and dose assessment

Abstract

Adaptive Radiation Therapy (ART) was developed based on Image-guided Radiation Therapy (IGRT) and it is the trend of photon radiation therapy. To get a better use of Cone Beam CT (CBCT) images for ART, the CBCT system model was established based on Monte Carlo program and validated against the measurement. The BEAMnrc program was adopted to the KV x-ray tube. Both IOURCE-13 and ISOURCE-24 were chosen to simulate the path of beam particles. The measured Percentage Depth Dose (PDD) and lateral dose profiles under 1cm water were compared with the dose calculated by DOSXYZnrc program. The calculated PDD was better than 1% within the depth of 10cm. More than 85% points of calculated lateral dose profiles was within 2%. The correct CBCT system model helps to improve CBCT image quality for dose verification in ART and assess the CBCT image concomitant dose risk.