Isotope specific calibration of a dose calibrator for quantitative functional imaging
AssigneeSiemens Medical Solutions USA, Inc.
InventorManojeet Bhattacharya
Life of this patent
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Abstract
For dose calibration in functional imaging, an amount of bias in a dose calibrator measurement of activity is determined using a spectroscopic detector. The bias may then be used to correct dose values for the same isotope used to determine a factory-based sensitivity of the functional imaging system. When local functional imaging systems are calibrated, any difference in sensitivity from the factory measured sensitivity may be due to local dose calibrator bias, so the difference in sensitivity is used to determine a local correction.
Claims20
A method for dose calibration for quantitative single photon emission computed tomography (SPECT), the method comprising:
- measuring a first activity of a radioisotope sample with a high-purity Germanium detector, the radioisotope sample having a radioisotope;
- normalizing the first activity by an efficiency of the high-purity Germanium detector;
- measuring a second activity of the radioisotope sample with a first dose calibrator of a first SPECT system;
- normalizing the second activity by an efficiency of the first dose calibrator;
- calculating a bias based on the normalized first and second activities;
- correcting a dose value of a radiotracer of the radioisotope with a difference in sensitivity based on the bias;
- determining the difference in sensitivity by applying the calculated bias to a table of dose values for the radiotracer, the table having values measured by a second dose calibrator remote from the first SPECT system unit.
A method for dose calibration for quantitative nuclear imaging, the method comprising:
- measuring a first measure of activity for a radioisotope;
- measuring a second measure of activity for the radioisotope;
- calibrating the first measure by a spectroscopic detector with a sensitivity of the spectroscopic detector for the radioisotope;
- calibrating the second measure of the activity for the radioisotope by a first dose calibrator of a first SPECT system with a sensitivity of the dose calibrator for the radioisotope;
- determining a bias from the first and second measures of the activity;
- correcting a dose value of a radiotracer of the radioisotope with a difference in sensitivity based on the bias;
- and
- determining the difference in sensitivity by applying the determined bias to a table of dose values for the radiotracer, the table having values measured by a second dose calibrator remote from the first SPECT system unit.
A system for cross-calibration of dose in functional imaging quantification, the system comprising:
- a radiotracer source;
- a spectroscopic detector for measuring a first activity of the radiotracer source;
- a first dose calibrator for measuring a second activity of the radiotracer source;
- a memory containing executable instructions;
- a processor configured to execute the executable instructions, the executable instructions causing the processor to:
- determine a bias of the second activity measured by the first dose calibrator from the first activity measured by the spectroscopic detector;
- cross-calibrate the dose with a difference in sensitivity based on the bias;
- and
- determining the difference in sensitivity by applying the determined bias to a table of dose values for the radiotracer, the table having values measured by a second dose calibrator of a second system remote from the first dose calibrator.
Dependencies are inferred from the claim text.