Calculation of perturbation correction factors for some reference dosimeters in high-energy photon beams with the Monte Carlo code PENELOPE

Mazurier, J.; Gouriou, J.; Chauvenet, B.; Barthe, J.

doi:10.1088/0031-9155/46/6/309

Cited by 17 publications

(17 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 and 17. PENELOPE has been applied to many different problems [18][19][20][21][22][23][24][25] and has been validated extensively. [26][27][28] PENE-LOPE was adapted to the specific requirements of the MANTIS simulation using PENEASY, a generic main program and accessory routines that allow easy configuration of PENELOPE.…”

Section: Iia Physics Modelsmentioning

confidence: 99%

Anisotropic imaging performance in breast tomosynthesis

et al. 2007

View full text Add to dashboard Cite

We describe the anisotropy in imaging performance caused by oblique x-ray incidence in indirect detectors for breast tomosynthesis based on columnar scintillator screens. We use MANTIS, a freely available combined x-ray, electron, and optical Monte Carlo transport package which models the indirect detection processes in columnar screens, interaction by interaction. The code has been previously validated against published optical distributions. In this article, initial validation results are provided concerning the blur for particular designs of phosphor screens for which some details with respect to the columnar geometry are available from scanning electron microscopy. The polyenergetic x-ray spectrum utilized comes from a database of experimental data for three different anode/filter/kVp combinations: Mo/Mo at 28 kVp, Rh/Rh at 28 kVp, and W/Al at 42 kVp. The x-ray spectra were then filtered with breast tissue (3, 4, and 6 cm thickness), compression paddle, and support base, according to the oblique paths determined by the incidence angle. The composition of the breast tissue was 50%/50% adipose/glandular tissue mass ratio. Results are reported on the pulse-height statistics of the light output and on spatial blur, expressed as the response of the detector to a pencil beam with a certain incidence angle. Results suggest that the response is nonsymmetrical and that the resolution properties of a tomosynthesis system vary significantly with the angle of x-ray incidence. In contrast, it is found that the noise due to the variability in the number of light photons detected per primary x-ray interaction changes only a few percent. The anisotropy in the response is not less in screens with absorptive backings while the noise introduced by variations in the depth-dependent light output and optical transport is larger. The results suggest that anisotropic imaging performance across the detector area can be incorporated into reconstruction algorithms for improving the image quality of breast tomosynthesis. This study also demonstrates that the assessment of image quality of breast tomosynthesis systems requires a more complete description of the detector response beyond local, center measurements of resolution and noise that assume some degree of symmetry in the detector performance.

show abstract

Section: Iia Physics Modelsmentioning

confidence: 99%

Anisotropic imaging performance in breast tomosynthesis

et al. 2007

View full text Add to dashboard Cite

show abstract

“…2 that is published and freely distributed with the PENELOPE code by the Nuclear Energy Agency ͑NEA͒. PENELOPE has been applied to many problems [5][6][7][8][9][10][11][12] and has been validated extensively. [13][14][15] PENELOPE was adapted to the specific requirements of the MANTIS simulation using PENEASY, 42 a generic main program and accessory routines that allow easy configuration of PENELOPE.…”

Section: A Physics Modelsmentioning

confidence: 99%

Anisotropic imaging performance in indirect x-ray imaging detectors

Badano¹,

Kyprianou²,

Sempau³

2006

Med. Phys.

View full text Add to dashboard Cite

We report on the variability in imaging system performance due to oblique x-ray incidence, and the associated transport of quanta (both x rays and optical photons) through the phosphor, in columnar indirect digital detectors. The analysis uses MANTIS, a combined x-ray, electron, and optical Monte Carlo transport code freely available. We describe the main features of the simulation method and provide some validation of the phosphor screen models considered in this work. We report x-ray and electron three-dimensional energy deposition distributions and point-response functions (PRFs), including optical spread in columnar phosphor screens of thickness 100 and 500 microm, for 19, 39, 59, and 79 keV monoenergetic x-ray beams incident at 0 degrees, 10 degrees, and 15 degrees. In addition, we present pulse-height spectra for the same phosphor thickness, x-ray energies, and angles of incidence. Our results suggest that the PRF due to the phosphor blur is highly nonsymmetrical, and that the resolution properties of a columnar screen in a tomographic, or tomosynthetic imaging system varies significantly with the angle of x-ray incidence. Moreover, we find that the noise due to the variability in the number of light photons detected per primary x-ray interaction, summarized in the information or Swank factor, is somewhat independent of thickness and incidence angle of the x-ray beam. Our results also suggest that the anisotropy in the PRF is not less in screens with absorptive backings, while the noise introduced by variations in the gain and optical transport is larger. Predictions from MANTIS, after additional validation, can provide the needed understanding of the extent of such variations, and eventually, lead to the incorporation of the changes in imaging performance with incidence angle into the reconstruction algorithms for volumetric x-ray imaging systems.

show abstract

“…The detailed description of the physics models [3] is published and freely distributed with the penelope code by the Nuclear Energy Agency (NEA). penelope has been applied to many problems [5][6][7][8][9][10][11][12] and has been validated extensively [13][14][15]. penelope was adapted to the specific requirements of the mantis simulation using peneasy, a generic main program and accessory routines that allow easy configuration of penelope.…”

Section: Methodsmentioning

confidence: 99%

Three-dimensional columnar CsI model for x-ray imaging system simulations using MANTIS: validating for noise, blur, and light output

2006

View full text Add to dashboard Cite

In previous work, we and others have focused the validation of detector models for computational simulations of imaging system performance on matching, to a small difference, specific aspects of the detector's performance, i.e., modulation transfer function or light output. In this work, instead, we selected three parameters that, together, represent a more complete description of the imaging properties of the phosphor screen to be modeled. The three performance parameters are the information or Swank factor determined from pulse-height spectra, the light output (either in absolute or relative scale), and the point-response function. Using this general methodology, we created screen models that exhibit good agreement with recent experimental measurements available in the literature, over a wide x-ray energy range (18-75 keV), and for front-and back-screen configurations. The models are being used in conjunction with mantis, a Monte Carlo code for simulating imaging systems that tracks x rays, electrons, and optical photons in the same geometric model, with x-ray and electron physics models from the penelope package, and optical physics models from detect-ii. This study allows us to incorporate realistic detector models into a detailed and complete Monte Carlo simulation of the entire imaging system, including the object and its absorbed dose map, and the properties of the imaging acquisition.

show abstract

Calculation of perturbation correction factors for some reference dosimeters in high-energy photon beams with the Monte Carlo code PENELOPE

Cited by 17 publications

References 9 publications

Anisotropic imaging performance in breast tomosynthesis

Anisotropic imaging performance in breast tomosynthesis

Anisotropic imaging performance in indirect x-ray imaging detectors

Three-dimensional columnar CsI model for x-ray imaging system simulations using MANTIS: validating for noise, blur, and light output

Contact Info

Product

Resources

About