X-ray simulation with the Monte Carlo code PENELOPE. Application to Quality Control.

Area of Science:

• Medical Physics
• Computational Physics

Background:

• Accurate X-ray energy spectrum knowledge is crucial for X-ray tube quality control (QC) to minimize patient radiation dose.
• Routine QC often measures indirect parameters due to the challenges of direct X-ray spectrum measurement.

Purpose of the Study:

• To evaluate Monte Carlo simulation codes (PENELOPE, MCNP5) as tools for verifying QC parameters.
• To simulate X-ray spectra, considering equipment specifics, and compare them with theoretical models.
• To perform a sensitivity analysis of simulation parameters influencing spectral accuracy and computational efficiency.

Main Methods:

• Utilized PENELOPE and MCNP5 Monte Carlo codes to simulate X-ray spectra, including Bremsstrahlung and characteristic X-rays.
• Compared simulated spectra against the theoretical IPEM 78 spectrum.
• Conducted a sensitivity analysis to identify key parameters affecting simulation outcomes, focusing on the FORCE factor.

Main Results:

• The FORCE factor was identified as the most influential parameter in PENELOPE simulations, significantly impacting computer time.
• Optimizing the FORCE factor is essential for achieving agreement between simulated and theoretical spectra while reducing computation time.
• The PENELOPE model can determine quality parameters like Half Value Layer (HVL), though high FORCE values increase computation time; depth dose assessment is feasible with lower FORCE values.

Conclusions:

• Monte Carlo simulations offer a viable method for verifying X-ray tube QC parameters.
• Careful optimization of simulation parameters, particularly the FORCE factor, is necessary to balance accuracy and computational efficiency.
• The developed PENELOPE model shows potential for various QC applications, with parameter tuning critical for specific quality metrics.