Scintillation camera utilizing energy dependent linearity correction
AssigneeSopha Medical Systems, Inc.
InventorsJohn C. Engdahl, Michel Pierfitte
Life of this patent
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Abstract
A scintillation camera is provided with multiple linearity correction maps which are accessed as a function of the value of the energy of a detected radiation event, so as to separately correct for spatial dislocation errors in multiple energy ranges as a function of detected position. The correction maps may be obtained by direct measurement of nonlinearities for each of the desired energy ranges individually, or sets of corrections for some energy ranges may be obtained by extrapolation calculation from correction factors which have been obtained by direct measurement.
Claims6
A method for correcting spatial coordinates of detected radiation events computed by a scintillation camera, comprising the steps of:
- determining the energy range of a detected radiation event;
- selecting a set of predetermined spatial coordinate correction factors as a function of the determined energy range of said detected event;
- retrieving correction factors from the selected set of predetermined spatial coordinate correction factors as a function of said computed spatial coordinates;
- and
- correcting said computed spatial coordinates with the retrieved correction factors.
A scintillation camera, comprising:
- a camera head including a detector for detecting an incident radiation event;
- means for computing spatial coordinates corresponding to the location of the detected radiation event;
- means for developing an energy signal proportional to the energy level of said detected radiation event;
- means for determining a range of energies into which said energy signal falls and generating a signal corresponding thereto;
- storage means for storing a plurality of sets of spatial coordinate correction factors, each corresponding to a particular energy range;
- means for selecting a set of spatial coordinate correction factors from said storage means as a function of said signal from said means for determining;
- means for retrieving correction factors from the selected set of spatial coordinate correction factors as a function of the computed spatial coordinates;
- and
- means for correcting said computed spatial coordinates with the retrieved correction factors.
A method of calibrating a scintillation camera, comprising the steps of:
- obtaining separate sets of spatial coordinate correction factors for each of a plurality of radiation events of different energy ranges;
- and
- storing the separately obtained sets of spatial coordinate correction factors in a storage memory of said scintillation camera along with the energy range to which each of said sets corresponds.
Dependencies are inferred from the claim text.