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

Abstract

A realistic knowledge of the energy spectrum is very important in Quality Control (QC) of X-ray tubes in order to reduce dose to patients. However, due to the implicit difficulties to measure the X-ray spectrum accurately, it is not normally obtained in routine QC. Instead, some parameters are measured and/or calculated. PENELOPE and MCNP5 codes, based on the Monte Carlo method, can be used as complementary tools to verify parameters measured in QC. These codes allow estimating Bremsstrahlung and characteristic lines from the anode taking into account specific characteristics of equipment. They have been applied to simulate an X-ray spectrum. Results are compared with theoretical IPEM 78 spectrum. A sensitivity analysis has been developed to estimate the influence on simulated spectra of important parameters used in simulation codes. With this analysis it has been obtained that the FORCE factor is the most important parameter in PENELOPE simulations. FORCE factor, which is a variance reduction method, improves the simulation but produces hard increases of computer time. The value of FORCE should be optimized so that a good agreement of simulated and theoretical spectra is reached, but with a reduction of computer time. Quality parameters such as Half Value Layer (HVL) can be obtained with the PENELOPE model developed, but FORCE takes such a high value that computer time is hardly increased. On the other hand, depth dose assessment can be achieved with acceptable results for small values of FORCE.

A Monte Carlo‐based dosimetric characterization of Esteya®, an electronic surface brachytherapy unit

“…It has been pointed out in the literature that modifications of the transport parameters C1 and C2 for high‐energy electrons in the target, even with small nonzero values, may affect water dosimetry . However, there is no evidence indicating that the use of VRIF may bias simulations in water . In our opinion, the most efficient strategy is to develop an EFEN by fixing the transport parameters only after the use of some VRT over the target.…”

“…Unlike other authors, we found a deterioration in the simulation efficiency with the use of C1 and C2 parameters in combination with VRIF F = 150 (see Fig. ).…”

Task-based measures of image quality and their relation to radiation dose and patient risk

“…The simulation tools that are most commonly used today are Monte Carlo simulations (e.g. EGS, MCNP, Fluka, Penelope and GEANT (Bielajew et al 1994, Baró et al 1995, Agostinelli et al 2003, Ferrari et al 2005, Allison et al 2006, Reed 2007, Ljungberg and King 2012, Pozuelo et al 2012). The models range from pure mathematical models (ICRP 1979, Zankl et al 1988) to various anthropomorphic voxel phantoms (Zubal et al 1994, Xu et al 2000, Petoussi-Henss et al 2002, Kramer et al 2004, Lee et al 2006, Menzel et al 2009, Xu and Eckerman 2010.…”

Facilidades de códigos de Monte Carlo para obter CSR

“…Muitas aplicações são encontradas na literatura utilizando o PENELOPE, com destaque para metrologia, mamografia, radiologia diagnóstica, entre outros. Bastante utilizado desde geometrias simples às mais complexas, como forma de estimar o comportamento de determinado sistema a ser estudado [22][23][24]. Este algoritmo de simulação pode ser aplicado para modelagens com energias iniciais entre 1 keV e 1 GeV.…”