Abstract: Objective:To investigate the effect of radiation dose of dualsource computed tomography (CT) dual energy singlephase enhanced scan in patients with esophageal cancer.
Methods:The prospective study was conducted. The clinicopathological data of 56 patients with esophageal cancer who were admitted to the Lishui Hospital of Zhejiang University between January 2015 and December 2016 were collected. All the patients were divided into the experimental group (undergoing dualsource CT dual energy singlephase enhanced scan) and control group (undergoing dualphase CT enhanced scan) by randomised block method. TNM classification of esophageal cancer (Seventh Edition) published by American Joint Committee on Cancer (AJCC) was used as a standard TNM staging. Two observers independently read films. All the patients underwent radical resection of esophageal cancer or palliative surgery, and then received adjuvant radiochemotherapy. Followup using outpatient examination and telephone interview was performed to detect postoperative survival of patients up to March 2017. Observation indicators: (1) consistencies of T staging, N staging and M staging; (2) accuracies of T staging, N staging and M staging (pathological results as a gold standard); (3) radiation dose of CT scan; (4) treatment and followup situations. The Kappa test was used for evaluating the consistency, κ≥0.75 as a good consistency, 0.40≤κ<0.75 as a normal consistency and κ<0.40 as a poor consistency. Comparisons of count data and ratio were done by the chisquare test. Comparisons of measurement data were analyzed by the t test.
Results:A total of 50 patients were enrolled in the study, including 25 in the experimental group and 25 in the control group. (1) Consistencies of T staging, N staging and M staging: all the 50 patients finished successfully CT scans. Two observers considered that consistencies of T staging, N staging and M staging in the 2 groups were normal (κ=0.452, 0.618, 0.729, P<0.05). Consistencies of N staging and M staging were superior to T staging. (2) The pathological results were used as a gold standard. Accuracies of T staging, N staging and M staging in the experimental and control groups were 72%, 76% and 88%, 84% and 92%, 88%, respectively, with no statistically significant difference between the 2 groups (x²=0.10, 0.37, 0.50, P>0.05). (3) Radiation dose of CT scan: volume CT dose index (CTDIvol), dose length production (DLP) and effective radiation dose (E) were (10.35±2.01)mGy, (400.63±34.13)mGy·cm, (5.61±0.47)mSv in the experimental group and (3.55±0.60)mGy, (140.66±10.89)mGy·cm, (1.98±0.17)mSv in the control group, respectively. There were statistically significant differences in CTDIvol and E between the 2 groups (t=16.23, 36.30, P<0.05). (4) Treatment and followup situations: of 50 patients, 43 patients received treatments, including 32 undergoing radical resection (11 receiving postoperative adjuvant chemotherapy), 6 undergoing palliative surgery, 3 receiving single radiotherapy and 2 receiving single chemotherapy. Thirtysix of 43 patients were followed up for 3- 18 months, with a median time of 6 months. During followup, 1year survival rate was 61.1%.
Conclusion:Dualsource CT dual energy singlephase enhanced scan in patients with esophageal cancer cannot reduce accuracy of TNM staging, but decreased effectively radiation dose.