Initial Evaluation of a Novel Slot-Scanning Technology for Pediatric Scoliosis Imaging
Abstract
Purpose
To evaluate a new slot scanning technology (True2Scale (T2S), Multitom Rax, Siemens Healthcare, Germany) and compare it with conventional EOS biplane slot scanning (EOS Imaging, France) for scoliosis examinations via phantom and retrospective patient studies.
Methods
Anthropomorphic phantom evaluations and dose measurements were performed before T2S clinical deployment. 25 adolescent patients who underwent scoliosis exams on both systems within one year were retrospectively identified. Images were anonymized and randomized for a blinded reader study, in which two radiologists rated image quality across 16 anatomy sites, overall exam quality, and implant depiction using four-point scales, and noted Risser scores. Patient organ doses and effective doses (ED) were estimated using PCXMC software (STUK, Finland). Linear mixed model (LMM) analyses were conducted to identify factors influencing image quality and ED.
Results
Among five options, T2S convolution kernel 2 was selected based on the overall best signal-noise and contrast-noise ratios, consistent with radiologist assessment. ED for comparable default T2S and EOS protocols were found to be similar. Clinically, posteroanterior (PA) projection was acquired in 22 EOS and 2 T2S exams due to system differences. Ultra-low-dose protocols were used in 3 EOS and 5 T2S exams per institutional follow-up procedures. Median (Quartile1, Quartile3) ED for EOS versus T2S was 0.125 (0.112, 0.156) versus 0.094 (0.070, 0.280) mSv for 18 two-view exams, and 0.068 (0.055, 0.072) versus 0.033 (0.023, 0.067) mSv for 7 frontal-only exams. Intraclass Correlation Coefficients between readers were 0.757 and 0.955 for image quality and Risser scores, respectively (both p<0.001). LMM analyses revealed lower ED with the ultra-low-dose protocol (p<0.001) and PA projection (p<0.05), as expected, but not with scanner system. System differences did not significantly influence image quality.
Conclusion
With appropriate protocol setup and convolution kernel 2, T2S showed comparable radiation dose and image quality to EOS with strong reader agreement.