表 1. Noise power spectrum average peaks and average spatial frequencies obtained for three reconstruction types (n=50) .

3种重建方式的噪声功率谱平均峰值和平均空间频率（n=50）

Item	FBP	IR	DL
NPS: Noise power spectrum; FBP: Filtered back projection; IR: Iterative reconstruction; DL: Deep learning.
NPS average peak/HU2·mm2	147.70	90.68	65.25
NPS average spatial frequency/mm−1	2.93	2.73	2.45