RESUMO
PURPOSE: To investigate the dose saving potential of direct-converting CdTe photon-counting detector technology for dedicated breast CT. MATERIALS AND METHODS: We analyzed the modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) of two detector technologies, suitable for breast CT (BCT): a flat-panel energy-integrating detector with a 70 µm and a 208 µm thick gadolinium oxysulfide (GOS) and a 150 µm thick cesium iodide (CsI) scintillator and a photon-counting detector with a 1000 µm thick CdTe sensor. RESULTS: The measurements for GOS scintillator thicknesses of 70 µm and 208 µm delivered 10% pre-sampled MTF values of 6.6 mm(-1) and 3.2 mm(-1), and DQE(0) values of 23% and 61%. The 10% pre-sampled MTF value for the 150 µm thick CsI scintillator 6.9 mm(-1), and the DQE(0) value was 49%. The CdTe sensor reached a 10% pre-sampled MTF value of 8.5 mm(-1) and a DQE(0) value of 85%. CONCLUSION: The photon-counting CdTe detector technology allows for significant dose reduction compared to the energy-integrating scintillation detector technology used in BCT today. Our comparative evaluation indicates that a high potential dose saving may be possible for BCT by using CdTe detectors, without loss of spatial resolution.
