Abstract
A tungsten anode spectral model using interpolating polynomials (TASMIP) was used to compute x-ray spectra at 1 keV intervals over the range from 30 kV to 140 kV. The TASMIP is not semi-empirical and uses no physical assumptions regarding x-ray production, but rather interpolates measured constant potential x-ray spectra published by Fewell et al. [Handbook of Computed Tomography X-ray Spectra (U.S. Government Printing Office, Washington, D.C., 1981)]. X-ray output measurements (mR/mAs measured at 1 m) were made on a calibrated constant potential generator in our laboratory from 50 kV to 124 kV, and with 0-5 mm added aluminum filtration. The Fewell spectra were slightly modified (numerically hardened) and normalized based on the attenuation and output characteristics of a constant potential generator and metal-insert x-ray tube in our laboratory. Then, using the modified Fewell spectra of different kVs, the photon fluence Φ at each 1 keV energy bin (E) over energies from 10 keV to 140 keV was characterized using polynomial functions of the form Φ(E)=a0[E]+a1[E] kV+a2[E] kV2+··· +(n)[E] kV(n) · A total of 131 polynomial functions were used to calculate accurate x-ray spectra, each function requiring between two and four terms. The resulting TASMIP algorithm produced x-ray spectra that match both the quality and quantity characteristics of the x-ray system in our laboratory. For photon fluences above 10% of the peak fluence in the spectrum, the average percent difference (and standard deviation) between the modified Fewell spectra and the TASMIP photon fluence was - 1.43% (3.8%) for the 50 kV spectrum, -0.89% (1.37%) for the 70 kV spectrum, and for the 80, 90, 100, 110, 120, 130 and 140 kV spectra, the mean differences between spectra were all less than 0.20% and the standard deviations were less than ~ 1.1%. The model was also extended to include the effects of generator-induced kV ripple. Finally, the x-ray photon fluence in the units of photons/mm2 per mR was calculated as a function of HVL, kV, and ripple factor, for various (water-equivalent) patient thicknesses (0, 10, 20, and 30 cm). These values may be useful for computing the detective quantum efficiency, DQE(f), of x- ray detector systems. The TASMIP algorithm and ancillary data are made available on line at http://www.aip.org/epaps/epaps.html.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1661-1670 |
| Number of pages | 10 |
| Journal | Medical Physics |
| Volume | 24 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 1997 |
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Keywords
- Computer model
- Computer simulation
- Detective quantum efficiency
- Spectra
- X ray
ASJC Scopus subject areas
- Biophysics
Cite this
An accurate method for computer-generating tungsten anode x-ray spectra from 30 to 140 kV. / Boone, John M; Seibert, J Anthony.
In: Medical Physics, Vol. 24, No. 11, 11.1997, p. 1661-1670.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - An accurate method for computer-generating tungsten anode x-ray spectra from 30 to 140 kV
AU - Boone, John M
AU - Seibert, J Anthony
PY - 1997/11
Y1 - 1997/11
N2 - A tungsten anode spectral model using interpolating polynomials (TASMIP) was used to compute x-ray spectra at 1 keV intervals over the range from 30 kV to 140 kV. The TASMIP is not semi-empirical and uses no physical assumptions regarding x-ray production, but rather interpolates measured constant potential x-ray spectra published by Fewell et al. [Handbook of Computed Tomography X-ray Spectra (U.S. Government Printing Office, Washington, D.C., 1981)]. X-ray output measurements (mR/mAs measured at 1 m) were made on a calibrated constant potential generator in our laboratory from 50 kV to 124 kV, and with 0-5 mm added aluminum filtration. The Fewell spectra were slightly modified (numerically hardened) and normalized based on the attenuation and output characteristics of a constant potential generator and metal-insert x-ray tube in our laboratory. Then, using the modified Fewell spectra of different kVs, the photon fluence Φ at each 1 keV energy bin (E) over energies from 10 keV to 140 keV was characterized using polynomial functions of the form Φ(E)=a0[E]+a1[E] kV+a2[E] kV2+··· +(n)[E] kV(n) · A total of 131 polynomial functions were used to calculate accurate x-ray spectra, each function requiring between two and four terms. The resulting TASMIP algorithm produced x-ray spectra that match both the quality and quantity characteristics of the x-ray system in our laboratory. For photon fluences above 10% of the peak fluence in the spectrum, the average percent difference (and standard deviation) between the modified Fewell spectra and the TASMIP photon fluence was - 1.43% (3.8%) for the 50 kV spectrum, -0.89% (1.37%) for the 70 kV spectrum, and for the 80, 90, 100, 110, 120, 130 and 140 kV spectra, the mean differences between spectra were all less than 0.20% and the standard deviations were less than ~ 1.1%. The model was also extended to include the effects of generator-induced kV ripple. Finally, the x-ray photon fluence in the units of photons/mm2 per mR was calculated as a function of HVL, kV, and ripple factor, for various (water-equivalent) patient thicknesses (0, 10, 20, and 30 cm). These values may be useful for computing the detective quantum efficiency, DQE(f), of x- ray detector systems. The TASMIP algorithm and ancillary data are made available on line at http://www.aip.org/epaps/epaps.html.
AB - A tungsten anode spectral model using interpolating polynomials (TASMIP) was used to compute x-ray spectra at 1 keV intervals over the range from 30 kV to 140 kV. The TASMIP is not semi-empirical and uses no physical assumptions regarding x-ray production, but rather interpolates measured constant potential x-ray spectra published by Fewell et al. [Handbook of Computed Tomography X-ray Spectra (U.S. Government Printing Office, Washington, D.C., 1981)]. X-ray output measurements (mR/mAs measured at 1 m) were made on a calibrated constant potential generator in our laboratory from 50 kV to 124 kV, and with 0-5 mm added aluminum filtration. The Fewell spectra were slightly modified (numerically hardened) and normalized based on the attenuation and output characteristics of a constant potential generator and metal-insert x-ray tube in our laboratory. Then, using the modified Fewell spectra of different kVs, the photon fluence Φ at each 1 keV energy bin (E) over energies from 10 keV to 140 keV was characterized using polynomial functions of the form Φ(E)=a0[E]+a1[E] kV+a2[E] kV2+··· +(n)[E] kV(n) · A total of 131 polynomial functions were used to calculate accurate x-ray spectra, each function requiring between two and four terms. The resulting TASMIP algorithm produced x-ray spectra that match both the quality and quantity characteristics of the x-ray system in our laboratory. For photon fluences above 10% of the peak fluence in the spectrum, the average percent difference (and standard deviation) between the modified Fewell spectra and the TASMIP photon fluence was - 1.43% (3.8%) for the 50 kV spectrum, -0.89% (1.37%) for the 70 kV spectrum, and for the 80, 90, 100, 110, 120, 130 and 140 kV spectra, the mean differences between spectra were all less than 0.20% and the standard deviations were less than ~ 1.1%. The model was also extended to include the effects of generator-induced kV ripple. Finally, the x-ray photon fluence in the units of photons/mm2 per mR was calculated as a function of HVL, kV, and ripple factor, for various (water-equivalent) patient thicknesses (0, 10, 20, and 30 cm). These values may be useful for computing the detective quantum efficiency, DQE(f), of x- ray detector systems. The TASMIP algorithm and ancillary data are made available on line at http://www.aip.org/epaps/epaps.html.
KW - Computer model
KW - Computer simulation
KW - Detective quantum efficiency
KW - Spectra
KW - X ray
UR - http://www.scopus.com/inward/record.url?scp=0030657556&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030657556&partnerID=8YFLogxK
U2 - 10.1118/1.597953
DO - 10.1118/1.597953
M3 - Article
C2 - 9394272
AN - SCOPUS:0030657556
VL - 24
SP - 1661
EP - 1670
JO - Medical Physics
JF - Medical Physics
SN - 0094-2405
IS - 11
ER -