Dynamic range and optimization strategies for radiochromic film calibration using gradient radiation fields

Area of Science:

• Medical Physics
• Radiotherapy Dosimetry

Background:

• Radiochromic film is crucial for radiotherapy dose verification.
• Optimizing calibration point distribution is essential for accurate film dosimetry.

Purpose of the Study:

• To optimize gradient positioning for uniform radiochromic film calibration.
• To assess the impact of physical wedge parameters on dose gradients and dynamic range.

Main Methods:

• Numerical parameterization of physical wedge profiles.
• Developed an optimization algorithm based on histogram bin height minimization.
• Evaluated field size, depth, and energy effects on dose dynamic range.

Main Results:

• Maximum dynamic range achieved with a 20x20 cm field at 5 cm depth.
• Optimized positioning required 7 exposures for 1-10 Gy and 8 exposures for 1-20 Gy.
• Demonstrated film calibration with optimized gradient positioning.

Conclusions:

• The study presents an optimized method for radiochromic film calibration.
• This approach enhances dosimetric accuracy and material efficiency in clinical settings.
• The methodology is adaptable for dynamic wedges.