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Objective To investigate the effect of adjusting tube current time product (mAs) according to head circumference index on head CT image quality and organ-specific-dose level based on Monte Carlo analysis platform.Methods A total of 92 patients including children and adolescents with different clinical symptoms undergoing head CT scan were prospectively selected between September 2017 and June 2018 in the First Hospital of Jilin University.Without limiting the size of the head circumference,there were 22 patients were selected as conventional group by random number table,whose head circumference was 48.1-59.2 cm.Low dose group was divided into following three subgroups according to different head circumferences:A group 54.1-57.0 cm (n=22);B group 51.1-54.0 cm (n=26) and C group 48.1-51.0 cm (n=22).Tube current time product was 250 mAs for conventional group,200 mAs for A group,150 mAs for B group and 100 mAs for C group,respectively.The organ-specific-radiation doses (brain,eye lens and salivary gland) were recorded by Monte Carlo analysis platform and the subjective and objective image quality score was evaluated.Analyses of the differences between four groups were compared with image quality score as well as organ-specific-radiation dose by single factor variance.Results Radiation dose to brain was conventional group (34.37±3.62),A group (25.91±0.99),B group (23.18±6.11) and C group (17.38 ± 3.23) mSv,respectively.The difference was of statistical significance in the four groups (F=54.51,P＜0.05).Dose to eye lens was conventional group (41.54± 1.04),A group (33.03±0.35),B group (26.18±2.72) and C group (20.88±4.45) mSv,with statistical significance in difference between the four groups (F=189.75,P＜0.05).Dose to salivary gland was conventional group (35.04 ± 4.94),A group (25.92 ± 0.99),B group (22.93 ± 6.54) and C (14.96±2.67) mSv,respectively,with statistical significance in difference between the four groups (F=65.74,P＜0.05).Image quality scores were respectively conventional group (4.97±0.13),A group (4.77 ± 0.49),B group (4.60 ± 0.49) and C group (3.98 ± 0.61),respectively,with statistical significance between them (F=3.89,P＜0.05),but without statistical significance in difference between the four groups (P ＞ 0.05).The signal-to-noise ratios of gray matter in A,B and C groups were conventional group (18.69 ± 3.55),A group (16.76 ± 2.87),B group (15.05 ± 2.80) and C group (13.65±2.53),respectively,without statistical significance in difference between the four groups (P＞ 0.05);The signal-to-noise ratios of white matter in conventional group (17.46±3.72),A group (15.54± 2.81),B group (13.71±2.43) and C group (11.77±2.18),respectively,without statistical significance in difference between the four groups (P＞0.05).Conclusions Adjusting the tube current time product (mAs) according to head circumference index of children and adolescents can make scanning program more personalized and reduce organ-specific-radiation doses to sensitive organs without compromise of image quality.
ABSTRACT
Alveolar soft part sarcoma (ASPS) is a kind of extremely rare malignant soft tissue sarcoma, which was first discovered and defined by American scholars in 1952. Its main manifestation is painless and slow growth mass, and distant metastasis often occurs in lung, bone, brain, liver with poor prognosis. In recent years, with the accumulation of the number of cases and the development of related technology, the diagnosis and treatment of ASPS have been improved greatly. However, the primary intracranial ASPS is still rare, this paper reviews the progress of primary intracranial ASPS, in order to provide help for its clinical diagnosis and treatment.
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<p><b>OBJECTIVE</b>To prepare the submicron emulsion of fresh Zhongjiefeng volatile oil.</p><p><b>METHOD</b>The Zhongjiefeng volatile oil submicron emulsion was obtained after passing the elementary emulsion through a high pressure homogenizer. The physical and chemical stability of the emulsion was evaluated with the stability parameter of centrifugation, appearance of emulsion and the pH. The formulation and processing factors were optimized by single factor reviewing and orthogonal experimental design.</p><p><b>RESULT</b>By controlling various processing factors and optimizing formulation, the stable submicron emulsion of Zhongjiefeng volatile oil was prepared. Its mean particle diameter was 164-169 nm with PDI 0.084-0.107 and Zeta electric potential was -40 mV.</p><p><b>CONCLUSION</b>The formulation and preparation technique of the emulsion is reasonable.</p>