Development of a three-dimensional dose evaluation method for computed tomography.

Area of Science:

• Medical Physics
• Radiological Imaging
• Radiation Dosimetry

Background:

• Computed tomography (CT) scans involve an X-ray tube orbiting a patient.
• Two-dimensional (2D) dose distributions can be visualized using radiochromic film in phantoms.
• Three-dimensional (3D) dose mapping is crucial for accurate radiation therapy planning and quality assurance.

Purpose of the Study:

• To evaluate the concept and methodology for creating a 3D dose map.
• To develop a phantom system using radiochromic film for 3D dose distribution acquisition.
• To assess coronal and axial plane dose distributions within CT phantoms.

Main Methods:

• Utilized half-cylindrical acrylic phantoms (10 and 16 cm diameter, 30 cm length) with sandwiched radiochromic film.
• Acquired 2D dose distribution images using an XR-QA2 film, image scanner, and processing software.
• Reconstructed 3D dose distribution by rotating 2D data and applying image processing techniques to the red channel of the film image.

Main Results:

• Successfully generated a 3D pixel value map representing dose distribution.
• Demonstrated the feasibility of creating cross-sectional color images from processed 2D data.
• Developed a reproducible dose measurement procedure for 3D dose distribution using the phantom system.

Conclusions:

• The developed methodology provides a viable approach for constructing 3D dose maps from CT scans.
• This technique enhances the ability to analyze complex radiation dose distributions in medical imaging.
• The study establishes a foundation for advanced phantom-based dosimetry in CT applications.