1. Mammography
  2. Radiography
Anode material:
Tube voltage:
 18 ... 40 kV

The default value for the air kerma of the initial spectrum is 1 mGy. The final air kerma can be defined later.
Calculate Initial Spectrum


Anode material:
Peak tube voltage:
 kV
Final air kerma:
 mGy


Filter object Filter attenuation properties Beam parameters behind filter Beam intensity quantities
material thickness / mm mass density / (g/cm³) photon fluence transmission factor energy fluence transmission factor air kerma transmission factor mean energy / keV air kerma half- value layer thickness / (mm AI) specific photon fluence * mm² * nGy photon fluence * mm² air kerma / mGy


 OR   Thickness: mm
Add Filter



Excel Export
Spectrum as CSV
Literature
[1]
John M. Boone, Thomas R. Fewell, Robert J. Jennings: Molybdenum, rhodium, and tungsten anode spectral models using interpolating polynomials with application to mammography; Medical Physics 24(12), 1883 - 1874, 1997

[2]
John M. Boone, J. Anthony Seibert: An accurate method for computer-generating tungsten anode x-ray spectra from 30 to 140 kV; Medical Physics 24(11), 1661 - 1670, 1997

[3]
T.R. Fewell, R.E. Shuping: Handbook of Mammographic X-ray Spectra; HEW Publication (FDA) 79-8071; Rockville, MD (1978)

[4]
T.R. Fewell, R.E. Shuping, K. Healy: Handbook of Computed Tomography X-ray Spectra; HHS Publication (FDA) 81-8162; Rockville, MD (1981)
Glossary
voltage ripple
difference between maximum and minimum value divided by the maximum value for a temporally periodic tube voltage (see Figure 8 in [2])

initial spectrum
the "raw" spectrum – without any filtering - emerging without any modification from John Boone's data (see [1] and [2])
John Boone's spectra – in his own nomenclature – are called "modified Fewell spectra” and provide an approximation
to the spectra from X-ray tubes being present in John Boone's laboratory during the investigations described in [1] and [2].
For mammography spectra the inherent filtering corresponds to 0.5 mm of Be, for radiography spectra it is equivalent to 1.1 mm of Al at 62.5 kVp

transmission factor
ratio between output value (having traversed the filter) and corresponding input value of some radiation intensity quantity (photon fluence, energy fluence, or air kerma)

photon fluence
mean number of photons per unit area

energy fluence
mean amount of photon energy per unit area
The energy fluence in an X-ray beam is equal to the product of the photon fluence and the mean spectral energy.

air kerma
mean absorbed energy per unit absorber mass deposited in dry air by an X-ray beam

air kerma half value layer
the thickness of an Aluminum filter generating an air kerma transmission (and thus also absorption) factor of 50 percent

specific photon fluence
ratio between photon fluence and air kerma

Output spectra
The numerical values for output spectra are provided in two-column ASCII files whose contents has to be understood as follows:
The entries in the first column indicate the photon energy in keV.
The entries in the second column indicate the corresponding mean number of photons per mm² and keV.

The spectral simulation is based on the concept of a "needle beam geometry".

In other words, it does not take into account any geometrical effects like e.g. the spatial beam divergence which manifests itself as the "inverse square law".

The investigation of special tube parameters like air kerma yield factors (unit: Gy/As) is beyond the scope of this simulation tool. Only spectral features are investigated.