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Contribution of photon counting CT to the detectability of lung nodules using ultra-low dose CT protocols: a phantom study

Year: 2025

Type: article

Abstract: Purpose To compare the image quality obtained with an energy-integrating detector CT (EID-CT) and a photon-counting CT (PCCT) in ultra-low dose (ULD) chest CT protocols for three patient morphology configurations. Materials and methods ULD-CT acquisitions were performed at Sn100 kV on PCCT and EID-CT using an image quality phantom. Different phantom sections were used to simulate standard, overweight and obese patients and the ULD levels were adapted to each section: 0.4, 0.8 and 1.6 mGy, respectively. Noise power spectrum (NPS) and task-based transfer function (TTF) were computed to assess noise magnitude, noise texture and spatial resolution, respectively. Detectability indexes (d′) were computed to model the detection of a high-contrast solid nodule (HCN). Results At all dose levels, noise magnitude values were significantly lower with PCCT than with EID-CT (−8.9 ± 0.4 %; p < 0.05). Values of average NPS spatial frequencies were significantly higher (p < 0.05) with PCCT (0.446 ± 0.010 mm −1 ) than with EID-CT mode (0.323 ± 0.011 mm −1 ). For the air insert, TTF values at 50 % were significantly lower for PCCT (0.719 ± 0.045 mm −1 ) than with EID-CT (0.916 ± 0.030 mm −1 ) at 1.6 mGy but similar for other dose levels (p < 0.05). For the simulated chest lesion, d′ values were significantly higher (p < 0.05) with PCCT than with EID-CT. The improvements in d′ values was 23.6 ± 5.5 % for HCN. Conclusion Compared with EID-CT, using PCCT makes it possible to reduce noise, improve noise texture and, above all, improve the detection of simulated high-contrast thoracic lesion in ULD CT protocols.

Source: Physica Medica

DOI: 10.1016/j.ejmp.2025.105180