Activity cross-calibration of unsealed radionuclides utilizing a portable ion chamber
OwnerHans-Sonke Friedrich Jansinventor
Life of this patent
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Abstract
A system and method for cross-calibrating a radionuclide at two separate locations (A and B) includes the use of a portable ion chamber configured to fit within a dose calibrator, which ion chamber receives a syringe containing a known volume of a sample of a radionuclide. The portable ion chamber and dose calibrator with the syringe is transported to another location, where a second syringe, identical to the first containing a second sample of the same volume of the same radionuclide is measured in a second dose calibrator.
Claims11
A method of cross-calibrating a radionuclide at two separate locations (A and B) comprising the steps of:
- (a) drawing up a known amount of activity, A0A, at location A at calibration time t0A into a pre-defined volume in a first syringe;
- (b) inserting the syringe into a portable ion chamber, and placing the ion chamber into a dose calibrator;
- (c) measuring the chamber's response by integrating charge for a period of time tiA and determining a calibration factor;
- (d) transferring the ion chamber and the first syringe, emptied and cleaned, or an empty second syringe identical to the first syringe, to location B;
- (e) drawing a second sample having the same volume of the same radionuclide into the cleaned and emptied syringe or second syringe, placing the syringe into the ion chamber, placing the ion chamber into a second dose calibrator, and measuring the ion chamber's response in the second dose calibrator for a second period of time;
- (f) determining the activity of the second sample by adjusting with the location A calibration factor;
- and
- (g) cross-calibrating the second dose calibrator with the first dose calibrator using the measured activity of the second sample.
A system for cross-calibrating a radionuclide at two separate locations (A and B) comprising:
- (a) a portable ion chamber defining a cavity to receive a first syringe used to draw up a known amount of activity, A0A, at location A at calibration time t0A into a pre-defined volume;
- (c) a first dose calibrator defining a cavity to receive the portable ion chamber and a second dose calibrator defining a cavity to receive the portable ion chamber;
- (d) a processor configured to:
- (i) in the first dose calibrator at location A, measure the chamber's response for a first sample volume in the first syringe, by integrating charge for a period of time tiA and determining a calibration factor;
- (ii) measure the ion chamber's response in the second dose calibrator for a second period of time, after the ion chamber and the first syringe has been transferred to location B, and a second sample having the same volume of the same radionuclide into a cleaned and emptied first syringe or second identical syringe, placing the cleaned or second syringe into the ion chamber, placing the ion chamber into a second dose calibrator,
- (iii) determine the activity of the second sample by adjusting with the location A calibration factor;
- and
- (iv) cross-calibrate the second dose calibrator with the first dose calibrator using the measured activity of the second sample.
Dependencies are inferred from the claim text.