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US 4,905,150 AGranted
X-ray diagnostics installation with mean parenchyma dose calculator
AssigneeSiemens Aktiengesellschaft
InventorsHorst Aichinger, Karlheinz Koehler
Life of this patent
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Abstract
An x-ray diagnostics installation, of the type suitable for mammography, includes a calculator, such as a computer, which calculates the mean parenchyma dose based on a prescribed relationship from exposure values. The mean parenchyma dose can be read from the computer by a printer to obtain a permanent record.
Claims3
An x-ray diagnostics installation for mammography exposures comprising:
- means for generating an x-ray beam in which an examination subject is disposed;
- means for recording an x-ray image formed by radiation attenuated by said examination subject;
- and
- means for calculating a means parenchyma dose D for said examination subject according to the following equations:
- ##EQU3## with f=1.03 (conversion factor)
- d=subject thickness in cm
- d.sub.F =thickness of the fatty tissue
- d.sub.F =0.5 cm for d.ltoreq.5.0 cm
- d.sub.F =1.0 cm for d.ltoreq.5.0 cm
- J.sub.E =k.multidot.(I.multidot.t)
- I=x-ray tube current
- t=exposure time
- k=calibration
- a=1/d.multidot.In J.sub.E /J.sub.A
- J.sub.A =exit dose.
12 more elements
Dependencies are inferred from the claim text.