To compare radiation dose and image quality between a slot-scanning system (SSS) and a dynamic flat-panel detector (DFD) in assessing scoliosis in children.

An experimental study was first performed with a phantom to assess the quality of each device. The clinical part included a prospective observational dosimetric and qualitative comparative study with acquisition of whole-spine X-ray: SSS (31 children), DFD (26 children). Institutional review board approval and informed consent were obtained. Dosimetric statistical analysis was performed from dose area product (DAP) and entrance skin dose measured by thermo-luminescent dosimeters localized in the cervical, thoracic and sacral areas. Assessment of the diagnostic quality (phantom and clinical) was realized by independent evaluation by 3 observers, using statistical analysis of quality score and inter-observer reproducibility.

DAP was equivalent with the 2 systems. Entrance skin dose was significantly higher with DFD in thoracic and pelvic regions (P<0.05). Image quality scores of the SSS were significantly better than DFD for a majority of criteria, in both phantom and clinical evaluations.

For scoliosis evaluation, the SSS, compared to the DFD system, offers enhanced image quality while reducing the entrance skin dose in the most radiosensitive areas.