Monte Carlo modeling of coherent scattering: influence of interference

In this study, the authors present Monte Carlo (MC) simulation results for the intensity and angular distribution of scattered radiation from cylindrical absorbers. For coherent scattering the authors have taken into account the effects of interference by using new molecular form factor data for the AAPM plastic materials and water. The form factor data were compiled from X-ray diffraction measurements. The new data have been implemented in the authors' Electron Gamma Shower (EGS4) Monte Carlo system. The hybrid MC simulation results show a significant influence on the intensity and the angular distribution of coherently scattered photons. It is concluded that MC calculations are significantly in error when interference effects are ignored in the model for coherent scattering. Especially for simulation studies of scattered radiation in collimated geometries, where small angle scattering will prevail, the coherent scatter contribution is highly overestimated when conventional form factor data are used.

[1]  J Persliden,et al.  Calculation of the small-angle distribution of scattered photons in diagnostic radiology using a Monte Carlo collision density estimator. , 1986, Medical physics.

[2]  R. H. Pratt,et al.  Rayleigh scattering by energetic photons: Development of theory and current status , 1993 .

[3]  Lellery Storm,et al.  Photon cross sections from 1 keV to 100 MeV for elements Z=1 to Z=100 , 1970 .

[4]  M J Yaffe,et al.  Coherent scatter in diagnostic radiology. , 1983, Medical physics.

[5]  J. H. Hubbell,et al.  Relativistic atomic form factors and photon coherent scattering cross sections , 1979 .

[6]  L. Morin.  Molecular Form Factors and Photon Coherent Scattering Cross Sections of Water , 1982 .

[7]  J F Williamson,et al.  Monte Carlo evaluation of kerma at a point for photon transport problems. , 1987, Medical physics.

[8]  H Bernstein,et al.  On the significance of very small angle scattered radiation to radiographic imaging at low energies. , 1983, Medical physics.

[9]  Y. Namito,et al.  Implementation of linearly-polarized photon scattering into the EGS4 code , 1993 .

[10]  D. Rogers,et al.  EGS4 code system , 1985 .

[11]  K Doi,et al.  Physical characteristics of scattered radiation in diagnostic radiology: Monte Carlo simulation studies. , 1985, Medical physics.

[12]  A. L. Hanson,et al.  Interaction of keV photons with matter and new applications , 1992 .

[13]  U Neitzel,et al.  X-ray diffraction measurements of some plastic materials and body tissues. , 1987, Medical physics.

[14]  On the significance of scattered radiation in industrial X-ray computerized tomographic imaging , 1994 .

[15]  A. Berroir,et al.  Calculation of x-ray single scattering in diagnostic radiology. , 1983, Physics in medicine and biology.