Positron CT apparatus and a timing correction method
AssigneeShimadzu Corporation
InventorsTomoaki Tsuda, Masanobu Sato
Life of this patent
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Abstract
A PET apparatus and a timing correction method of this invention select two target gamma-ray detectors which count coincidences, select a reference detector which is one detector out of the two selected gamma-ray detectors, select a gamma-ray detector different from the other, opposite detector, and when repeating the selection, make a time lag histogram concerning two gamma-ray detectors selected in the past a reference, and correct a time lag histogram concerning gamma-ray detectors selected this time based on the reference. By repeating an operation to make the corrected time lag histogram concerning the two gamma-ray detectors a new reference, an optimal time lag histogram can be obtained without repeating many measurements and computations.
Claims5
A timing correction method for use in counting coincidences of radiation released from a positron-emitting radioactive drug given to a patient, the timing correction method comprising:
- a histogram correcting step, in connection with a time lag histogram showing a count value distribution of time lag variations for each pair of detectors which count coincidences of the radiation, for:
- (i) selecting a first detector as a reference detector and a second detectors as a count detector which count coincidences, to obtain a time lag histogram of the first detector and the second detector, and selecting a group of detectors including the second detector,
- (ii) selecting a detector different from the second detector from the group of detectors,
- (iii) correcting a time lag histogram of the first detector and the selected different detector using the time lag histogram of the first detector and the second detector,
- (iv) newly selecting a detector, which has not been previously selected, from the group of detectors, and correcting a time lag histogram of the first detector and the newly selected detector using the time lag histogram of the first detector and the second detector,
- (v) repeating (iv) until all of the detectors in the group of detectors are subjected to (iv), and
- repeating (i)-(v) by selecting a new reference detector, a new counter detector and a new group of detectors until all of a plurality of detectors in a positron CT apparatus are subjected to the selection and correction, the new reference detector being selected from a previously selected group of detectors.
Dependencies are inferred from the claim text.