A method for multichannel dosimetry with EBT3 radiochromic films

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiological Imaging

Background:

• Radiochromic films are widely used for radiation dosimetry.
• Accurate dose measurement is critical for effective radiation therapy.
• Existing multichannel dosimetry methods have limitations in handling film disturbances.

Purpose of the Study:

• To present an improved multichannel dosimetry method for radiochromic films.
• To incorporate information from unexposed film images to enhance accuracy.
• To evaluate the performance of the new method against existing techniques.

Main Methods:

• The proposed method applies perturbations to scanned dose data, considering color channel dependency.
• Comparison with previous multichannel and single-channel methods using depth dose profiles and perpendicular dose maps.
• Evaluation of 30 intensity-modulated radiation therapy (IMRT) quality assurance tests using gamma analysis.

Main Results:

• The improved method shows better agreement with experimental measurements and treatment planning systems.
• Statistically significant improvements in mean gamma pass rates were observed.
• The coefficient of variation was comparable across methods over a wide dose range.

Conclusions:

• The enhanced multichannel dosimetry method effectively mitigates common disturbances in radiochromic films.
• This method leads to superior gamma analysis results compared to existing approaches.
• The improved accuracy supports more reliable radiation dose assessment in clinical settings.