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Objective To investigate the relation between 18F-FDG PET/CT metabolic parameters and the clinicopathological characteristics of colorectal cancer (CRC) patients. Methods We included 358 CRC patients who met the admission criteria. 18F-FDG PET/CT scans were performed before any treatment. Maximum standard uptake, average standard uptake, tumor metabolic volume (MTV) and total glycolysis (TLG) of the primary lesion of CRC were measured and calculated. The correlation of metabolic parameters with lesion location, pathological profile and TNM staging were investigated through Mann-Whitney U test and Kruskal-Wallis test. Results The MTV and TLG values in the primary foci of colon cancer were the highest, followed by sigmoid cancer and the lowest in rectal cancer, with statistically significant differences between the groups (P < 0.001). SUVmax values of poorly/poorly-moderately differentiated colorectal cancer were higher than those of moderately/well differentiated colorectal cancer (P=0.028). MTV values of primary mucinous adenocarcinoma were higher than those of primary adenocarcinoma (P=0.023). MTV and TLG values were higher in T4 lesions than those in T2-3 lesions (P=0.0001, P=0.007); SUVmax and SUVmean values of sigmoid carcinoma with distant metastasis were lower than those without distant metastasis(P=0.015, P=0.011). Conclusion The metabolic parameters of CRC are correlated with the lesion location, pathological features and TNM staging, which could partly reflect the pathological characteristics and heterogeneity of CRC.

In order to solve the problem of three-band bandpass signal aliasing, a delay-adjustable third-order bandpass sampling structure is proposed. By designing a digital anti-aliasing filter, the alias-free reception of three-band bandpass signals can be realized. The simulation results are given, the signal is reconstructed and the anti-aliasing performance is analyzed. After the three-passband signal passes through the anti-aliasing filter, the signal output signal-to-noise ratio can be above 28 dB. This method solves the bandpass. The multi-signal aliasing problem in sampling increases the sampling frequency selection range, which reduces the hardware burden and improves the flexibility of the software radio.