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Objective To investigate the stomach of low-dose spiral CT scan program. Materials and Methods 1. Research object and Equipment: 40 patients, CT scans before they are confirmed by endoscopy gastric cancer. Use SomatomEmotion single-slice spiral CT scanner. (2) Inspection method: (1) preparation and scanning technology scans of 40 patients with gastric cancer were randomly divided into four groups (80mAs group, 50mAs group, 30mAs group, 24mAs groups of 10 cases) lines of different low-dose CT scan of the stomach , and the same line of each patient scan range conventional dose (120mAs) scans. Patients were in the fasting state demanding oral warm water 800-1000ml. Scan parameters: tube voltage 130 kV, slice thickness 8 mm, a width of the collimator 8 mm, table speed 12. 5 mm, pitch 1.5, scan time 13-16 seconds. Low-dose CT tube current were used 80 mAs, 50 mAs, 30 mAs, 24 mAs. (2) image observation and evaluation will rebuild axial images at the appropriate window width and window level observed in conventional dose CT images as a reference standard to evaluate the image quality of low dose levels. CT imaging results from the three with senior independent blinded radiologists read the piece, there are differences prevail when consensus evaluation. (3) Measurement of radiation dose CT workstation automatically display a variety of conditions, single-dose CT scans weighted index (CTDIw value), unit of radiation dose: mGy. 3 for each dose group was treated group image quality (ie, conventional dose and low dose accordingly between) differences for matching non-parametric rank sum test, P lt; 0.05 considered statistically significant. Different low-dose group difference in image quality between the groups long on group level data comparable rank sum test, P lt; 0.01 was considered statistically significant. All data applications SPSS13.0 software package deal. Results 1 right stomach, gastric wall thickening and lumps, stomach cavity clearance and organ-definition display interface between the low-dose 80mAs, 50mAs compared with conventional dose 120mAs scan when the group no significant difference in image quality ( P gt; 0.05); while 24mAs scan, test groups were statistically significant differences in memory (P lt; 0.05), but the actual statistics show that although the image quality is worse than the reference image, but did not affect the lesions; 30mAs scanning, for stomach, gastric wall thickening and no effect on tumor display clarity, image quality within the group was not statistically significant (P gt; 0.05), while the gap on the stomach cavity and organs of the interface between the display sharpness , despite the difference in image quality within the group The statistical test showed significant (P lt; 0.05), but the actual statistics show that although the image quality is worse than the reference image, but no effect on the lesions. The image quality of low-dose groups were significantly different (P lt; 0.01), on the stomach, gastric wall thickening and mass-definition display, the image quality between the two groups were significantly different (P lt; 0.01), 24mAs with other low-dose group dose groups had significant difference (P lt; 0.01), while other low-dose groups were not statistically significant (P gt; 0.01). The stomach cavity and organs of the interface between the gap-definition display, in addition to 24mAs dose group and 80mAs dose groups were significant differences (P lt; 0.01), other low-dose groups were not statistically significant (P gt; 0.01). (2) on the liver, spleen and other organs of the real definition display, 80mAs scanned image quality obtained when the group was not statistically significant (P gt; 0.05); to 50mAs, 30mAs, 24mAs scan, the study of the liver , spleen and other organs of the substance decreased sharpness, image quality within the group there were statistically significant difference test (P lt; 0.05). 50mAs, 30mAs scan image quality of actual statistics show that although the difference in the reference image, but did not affect the lesions; to 24mAs scan, 100% (10/10) of the object of study of the liver, spleen definition display fuzzy affect the observation. In addition 30mAs image quality between the two groups with no statistical significance between 50mAs (P gt; 0.01), the low-dose group than showing statistical significance (P lt; 0.01). 3 to 120mAs as the standard, 80mAs, 50mAs, 30mAs, 24mAs group of single-dose CT scans weighted index CTDIw (mGy) were reduced by 33%, 58%, 75%, 80%. Conclusion In gastric cancer screening, without affecting the diagnostic accuracy of the premise, low-dose 3 0mAs scan obtained with conventional doses of the same image information and image quality, and the single-dose CT scans weighted index (CTDIw) reduced 75%, to minimize the radiation dose the patient received. Visible lower tube current is an effective way to reduce the radiation dose.
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