Feasibility Invertigation Of Individualized Low-dose Scan In Preoperative Evaluation Of Colorectal Cancer With Dual-source Computed

Objective:To evaluate the feasibility of low-dose dual-source CT undergoing individual adaptedexamination protocol in the preoperative T staging of rectal cancer.Materials and Methods:Eighty patients with histological proven rectal cancer were enrolled. Half of themwere randomly selected to be undertaken low-dose dual-source CT with individual adaptedexamination protocol. The other half, as a control group, were scanned normal dual-sourceCT technique. Sensitivity and specificity of low-dose group and normal group relative tothe pathologic staging were calculated respectively. Then diagnostic accuracy wasstatistically compared between two groups. CT dose index volume and dose-length productof patients was measured, and effective dose was estimated and compared between twogroups.Results:The accuracies of normal group and low-dose group were93.75%and92.5%,respectively. There were no statistical difference between them(t=0.81,P>0.05). Diagnosticaccuracy of TNM staging between two groups appeared consistent with t=0.81(P>0.05)forT-stage, t=0.68（P>0.05）for N-stage and100%for M-stage. The average effective dosesof normal group and low-dose group were6.44and3.12, respectively. The latter issignificantly lower than the former (t=2.566,p<0.05).Conclusions:With individual adapted examination protocol in dual-source CT the patient dose canbe reduced significantly without affecting the accuracy in T-staging diagnosis of rectalcancer.