[Study of Dose Recalculation Method on Overriding Lung Density Using CBCT Image in the Thorax]

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Accurate absorbed dose calculation is crucial for adaptive radiotherapy (ART) using on-board cone beam computed tomography (CBCT) in image-guided radiation therapy (IGRT).
• Existing methods face challenges with lung density variations in patient thorax conditions, impacting accuracy.
• A simple and precise dose calculation method is needed for ART.

Purpose of the Study:

• To propose a novel, simple, and accurate dose recalculation method for CBCT images in ART.
• To address the challenge of varying lung densities in dose calculations for lung cancer patients.
• To improve the precision of dose calculations in image-guided radiation therapy.

Main Methods:

• Developed a new dose recalculation procedure for CBCT images.
• Implemented a method to override and account for varying lung densities.
• Validated the method by comparing CBCT dose recalculation with the original treatment plan.

Main Results:

• The proposed method achieves accurate dose calculation, considering diverse patient lung densities.
• The technique effectively excludes artifacts caused by overriding lung density variations.
• The dose error between CBCT dose recalculation and the treatment plan was within ±1%.

Conclusions:

• The new method is a valuable tool for accurate dose calculation using CBCT images in ART.
• This approach enhances the reliability of adaptive radiotherapy, especially for lung cancer patients.
• The ±1% dose accuracy demonstrates the clinical utility of this method for IGRT.