Method and Apparatus for Sensitivity Calibration

A method of identifying a miscalibrated dose calibrator, the method comprising:

• affixing a calibration radioactive source relative to a source holder;
• positioning the source holder in a dose calibrator;
• measuring radioactivity of the source using the dose calibrator;
• computing a deviation of the measured radioactivity from a precalibrated radioactivity value that has been corrected for decay that has occurred since a precalibration time;
• responsive to a determination that the computed deviation is outside a range specified by a predetermined threshold, displaying an indication that the dose calibrator is miscalibrated.

A radioactive source comprising:

• a radioactive isotope encapsulated in an enclosure;
• a handle portion having an axis aligned with the enclosure;
• and
• a substantially conical transition portion connecting the enclosure and the handle portion, wherein the transition portion is aligned along the axis;
• wherein an angle defined between the axis and a surface of the transition portion is configured to minimize a number of Compton-scattered gamma photons emitted by the isotope that are collimated by a collimator and detected by a detector of a gamma camera.

A device comprising:

• a radioactive point source;
• a collimator;
• a gamma ray detector configured to detect gamma photons emitted by the radioactive point source and passed through the collimator;
• one or more computer processors;
• and
• a non-transitory computer readable medium having instructions embodied tangibly thereupon, the instructions when executed configured to cause the one or more processors to perform operations of normalizing a sensitivity of a gamma camera, the operations comprising:
• computing a system-specific planar sensitivity for a combination of the collimator and detector using a number of gamma photons acquired, a time duration of acquisition of the number of gamma photons, and precalibrated radioactivity data of the radioactive point source corrected for decay that occurred after a precalibration time;
• computing a deviation of the computed system-specific planar sensitivity from a class standard sensitivity value for a combination of the radioactive point source, the collimator, and the detector;
• and
• scaling a class standard sensitivity value for a combination of a radiopharmaceutical, the collimator, and the detector by the computed deviation, to yield a scaled system-specific sensitivity value for the radiopharmaceutical.