Dependence of image quality on geometric factors in breast tomosynthesis

摘要: Purpose: Accurate and precise knowledge of the geometric relationships between physical components (x-ray source, pivot point, elements x-ray detector) critically influences quality reconstructed images in digital breast tomosynthesis (DBT). The sensitivity image reconstruction to inaccuracies is investigated by simulation formation for a DBT system. Methods: A mathematical partial isocentric system described. block “phantom” containing small calcific particles used evaluate effect three linear angular parameters on localization structures within lesion contrast. Two types errors are studied: fixed offset random interprojection context filtered back projection algorithm. Results: It shown that, general, lead little degradation quality. However, lack precision can cause loss contrast introduce artifacts. For example, mismatches gantry angle 0.14° (standard deviation) reduce intensity 20%. Reconstruction particularly sensitive detector yaw mismatches; even (0.31°) Interprojection variations also errors. if projections occur these not accounted for, standard deviation 0.34° be expected induce 1 mm root-mean-square error shift location. Conclusions: In acquisition DBT, sensitivities six were evaluated. Image reconstructions relatively tolerant except yaw. uncorrected losses localization. Lesion affected more strongly compared tomosynthesis.