Application Of Low-dose Multi-slice CT Scanning In Diagnosis And Treatrment Of Patients With Hepatocellular Carcinoma

Objective: To evaluate the value of low-dose technique to reduce theradiation dose in multi-slice CT scanning in abdominal imaging of patients withhepatocellular carcinoma.Methods: Part one:66patients were divided into two groups.33patients ingroup A, underwent conventional-dose multi-slice CT examination by Spiralscan;33patients in group B, underwent low-dose multi-slice CT examination byAxial scan.Part two:27patients with hepatocellular carcinoma all had abdomalCT examination twice. First visit patients were in group C, underwentconventional-dose MSCT examination by Spiral scan; Return visit patients ingroup D, underwent low-dose MSCT examination by Axial scan. All groupsexamined with120KV, Auto mA, Noise Index=9, rotation time0.6/cycle, scanslice thickness5mm,underwent plain scans, arterial phase scans, and portalvenous phase scans. The image quality scores and image noises and radiationdoses were compared in groups A、B and C、D.Results: Part one: The image quality score in groups A was4.63±0.41;The image quality score in groups B was4.48±0.44.The image quality scores in groups A and B showed no statistical difference (P＞0.05). The image noisein group A plain scanned was10.45±1.74; The image noise in group Aarterial phase scanned was12.25±1.85; The image noise in group A portalvenous phase scanned was11.39±2.24. The image noise in group B plainscanned was10.31±0.82; The image noise in group B arterial phase scannedwas12.50±1.16; The image noise in group B portal venous phase scannedwas12.09±1.34.The image noises had no significant difference in bothgroups (P＞0.05).The radiation dose in group A was（5.70±2.19）mSv; Theradiation dose in group B was（3.65±1.01）mSv. There were significantdifference in radiation doses between groups A and B (P＜0.01).Part two:Theimage quality score in groups C was4.93±0.40; The image quality score ingroups D was4.48±0.45.The image quality scores in groups C and D showed nostatistical difference (P＞0.05). The image noise in group C plain scanned was10.43±1.81; The image noise in group C arterial phase scanned was12.19±1.85;The image noise in group C portal venous phase scanned was11.53±2.31. Theimage noise in group D plain scanned was10.29±0.85; The image noise ingroup D arterial phase scanned was12.42±1.19; The image noise in group Dportal venous phase scanned was12.00±1.31.The image noises had nosignificant difference in both groups (P＞0.05).The radiation dose in group Cwa（s5.74±2.04）mSv; the radiation dose in group D wa（s3.51±0.90）mSv. Therewere significant difference in radiation doses between groups C and D (P＜0.05).Conclusions: Axial scan and Auto mA technique provide adequate imagequality without loss of diagnostic information.The radiation dose much lowerthan the conventional-dose MSCT examination.