Tomography using approximately coincident annihilation-photon detections to constrain an internal emission distribution. A calibrated model accounts for propagation, detector response, unrelated coincidences and scattering.
A pair of nearly simultaneous detector events treated as a candidate two-photon positron annihilation. True unscattered pairs define a coincidence line of response. For attenuation along one such line, the complementary survival path integrals add to the full chord and are independent of the annihilation depth.
The distance between positron emission and annihilation. Its distribution introduces a blur even if the subsequent line of response is measured perfectly.
Coincidence imaging using the detection-time difference to estimate annihilation position along a line of response. For timing difference , displacement from the midpoint is .
The line joining two coincident photon detections in ideal two-photon annihilation imaging. Finite detector size, non-collinearity and positron travel limit its relation to the original decay position.
A line defined by an approximately coincident detector pair in annihilation-photon tomography. An event constrains a possible annihilation location to that line within instrumental and physical uncertainties. Time-of-flight data can add a position constraint along it; attenuation, scattering and random coincidences change the forward model.
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