Objective To optimize image quality and radiation dose of infant chest digital radiography and to explore feasibility of reducing tube voltage and adjusting according to infant chest area. Methods 0 to 3-year-old infants were randomly divided into two average groups of 0- and 1-3 year-old, and then each age group was randomly assigned to optimization and control groups in digital radiography. Measurement of radiation dose used dose area product (DAP). Mean DAP between groups was compared by using t test, and the image quality of optimization was compared by rank sum test. Results A total of 400 cases of 0 to 3-year-old infants were identified, and finally 391 cases of infants anteroposterior chest image were included, including 196 cases in the optimization group (0-years: n=91; 1-3 years: n=105) and 195 cases in the control group (0-years: n=103; 1-3 years: n=92). The results showed: there were significant differences in the mean DAP in 0-years, 1-3 years and total infants between the optimization group and the control group (all P valuelt;0.05). The DAP of the optimization group was lower, and reduction of DAP was approximately 21.6% compared to the control subject. The Wilcoxon signed-rank test showed the difference of subjective evaluation of image quality was significantly different (P=0.000). High-quality image of the optimization group increased approximately 43.9% more than control subject. Conclusion Reducing tube voltage and adjusting according to infants chest area can not only reduce the radiation dose but also improve image quality in digital radiography.
【Abstract】Objective To investigate the irradiating effect of low intensive microwave (LIM) on pathological process of blood vessel restenosis(RS) and assess the probability of LIM irradiation to prevent was used RS.Methods Fortyfour male healthy New Zealand rabbits were randomly divided into 2 groups. Fogarty catheter traumatize to the tunica intima of iliac artery so as to establish RS models. Two thousand four hundred and fifty MHz microwave with different power of 2 ,5 and 10 mW/cm2 was used, locally to irradiate EIA in irradiating group (1 h/d). Specimens were obtained at different time of 3,7,14 and 28 d after operation. Morphological changes of tissues were observed with HE and EF staining and the area of tunica intima, tunica media and the rate of cavity stenosis were analyzed with image analysis system; apoptosis was detected with TUNEL; phenotype and microstructure of VSMC were observed with TEM. Results After microwave irradiating, inflammatory reaction in early period was suppressed, mural thrombus decreased, the proliferation and migration of VSMC depressed, the area of tunica intima and the rate of cavity stenosis obviously reduced comparing with the control group (P＜0.01). The rate of apoptosis cells showed that there were no obvious differences among each group on 3 d after operation (Pgt;0.05). At other different time, however, the rate of apoptosis cells in irradiating groups obviously increased than that of the control group (P＜0.01), particularly in the one with power of 5 mW/cm2 .The number of synthesis form VSMC in the control group occupied (93.50±3.45)% of the total number of VSMC on 14 d after operation. Most of VSMC appear contractile in irradiating group in which a lot of morphological changes of apoptosis in fibroblast and VSMC existed.Conclusion LIM irradiation could obviously prevented from pathologic procedure of RS. After LIM irradiating, inflammatory reaction in early period is suppressed, the proliferation and migration of VSMC depressed. LIM irradiation promotes cell apoptosis, effectively prohibites the occurring and development of RS. LIM irradiation has had relationship between quantity and effect, power span to effectively prohibit RS, particularly in the one with power of 5 mW/cm2.
Objiective To observe the changes of angioarchitecture of the optic disc in cats eyes after radial optic neurotomy (RON). Methods Ten healthy adult cats underwent unilateral RON randomly in 10 eyes as an operative group in this trial, and the fellow eyes (10 eyes) were as the control group. The colophony samples of vascular angioarchitecture of 20 eyes were made 90 days after RON and scanning electron microscope was used for the observation. Results In the control group, the blood supply of optic disc mainly came from the short posterior ciliary artery, pial artery, and retinal ciliary artery; the choroidal capillary vessels around the optic disc didnprime;t take part in the blood supply in the anterior area; retinal central vascular system and complete arterial circle around the optic nerves were not seen. In the operative group, a V-shaped defect of the optic disc, retinal blood vessels and choroidal capillary vessels was found at the surgical incision; no injury of retinal blood vessels and choroidal large vascular layer was seen, and neovascularization at the incision were not found. Conclusions RON may cause the vascular defect of the optic disc and the peripheral local tissues. The depth of the incision doesnprime;t reach the Zinn-Hallers circle. (Chin J Ocul Fundus Dis, 2007, 23: 170-172)
【摘要】 目的 评价64层螺旋CT低剂量冠状动脉血管成像的价值。 方法 2009年1-6月157例患者随机分为3组，常规剂量组（A组）管电流量采用1 000 mAs，两个低剂量组（B、C组）分别采用800、600 mAs。对3组的图像质量、噪声、CT剂量指数（CTDI）、剂量长度乘积（DLP）和有效剂量（ED）进行评估。 结果 A、B、C组图像噪声分别为20.50±3.23、23.02±3.05和26.28±2.58，组间差异均无统计学意义（Pgt;0.05）；A、B、C组的CTDI分别为（58.7±0.23）、（46.98±2.27）、（35.28±3.56） mGy，DLP分别为（1 050.88±89.63）、（846.21±57.86）、（641.13±32.15） mGy?cm，ED分别为（14.78±2.56）、（11.85±1.87）、（8.98±1.15） mSv，B、C组的CTDI、DLP、ED均明显低于常规剂量A组（Plt;0.05），C组的CTDI、DLP、ED均为3组中最低值。 结论 64层螺旋CT冠状动脉血管检查，采用600 mAs管电流量获得的冠脉图像既可满足诊断需要，又可使患者接受的辐射剂量降低。【Abstract】 Objective To evaluate the best tube current for low-dose radiation CT in coronary artery imaging by 64-slices multi-detector CT. Methods From January to June 2009, a total of 157 consecutive patients were randomly divided into 3 groups: group A (conventional group): 1 000 mAs; group B: 800 mAs; group C: 600 mAs. The image quality, noise, CT dose index (CTDI), dose length product (DLP) and effective dose (ED) in each group were measured and compared respectively. Results The image noise scores in group A, B, and C were (20.50±3.23), (23.02±3.05) and (26.28±2.58), respectively. There was no statistically significant difference among the three groups in the two indexes (Pgt;0.05). The CTDI in group A, B and C were (58.7±0.23), (46.98±2.27), and (35.28±3.56) mGy, respectively; the DLP in each were (1 050.88±89.63), (846.21±57.86), and (641.13±32.15) mGy?cm, respectively; the Ed were (14.78±2.56), (11.85±1.87), and (8.98±1.15) mSv, respectively. All of the differences among the three groups in CTDI, DLP and ED were statistically significant (Plt;0.05). Conclusion The image with 600 mAs as tube current in the coronary artery imaging of 64-slices multi-detector CT could fulfill the need of the diagnosis, and the radiation dose is apparently lower than the conventional scan.
Objective To investigate the effects of ectomesenchymalstem cells on hematopoiesis after total body irradiation in rats. Methods The primary ectomesenchymal stem cells were isolated from E11.5 SD fetal mandibular processes by 25g/L trypsin and cultured with DMEM/F12. The morphology and growthrate were observed by inverted microscope. Eighty SD male rats randomly dividedinto ectomesenchymal stem cells group (n=20), fibroblast group(n=20), saline group(n=20) and control group(n=20), the first three groups were irradiated with 60Co γ rays at 6.0 Gy. The number of their bone marrow nucleated cells was counted after 4 weeks; the forming ability of colony-forming unit-granulocyte macrophage(CFU-GM) and histopathology of bone marrow were also observed. Results The cultured cells displayed monolayer growth and fibroblast-like with 2-4 processes. The ectomesenchymal stem cells could increase the number of bone marrow nucleated cells and peripheral blood white cell count, and improve the forming ability of CFU-GM. After 4 weeks of transplantation, the number of the peripheral blood white cells in group A was more than that in groups B and C(Plt;0.05), the contents of Hb in groups A and D was significantly higher than those in groups B and C(Plt;0.0). After 4 weeks, the bone morrow nucleated cells in group A were significant more than those in groups B and C(Plt;001); CFU-GM in groups A and D was higher than that in groups B and C(Plt;0.01). Conclusion Ectomesenchymal stem cells have characteristics of stem cells. It may improve hematopoiesis recovery of irradiated rats.
ObjectiveTo discuss the value of dual-source CT Flash scanning in reducing the dose of radiation in 3D cardiac imaging. MethodWe collected 60 patients from March to August 2014 who should undergo cardiac 3D CT scanning before radiofrequency ablation. They were randomly divided into group A and B with 30 in each. Patients in group A underwent flash technology scanning, while those in group B accepted conventional retrospective electrocardiography-gated scanning. CARE Dose techniques were used to collect data. Scanning parameters were the same for both groups:collimation was 128×0.6 mm, reconstruction thickness was 0.75 mm, reconstruction interval was 0.7 mm, and field of view was 180-200 mm. After image acquisition, we measured the CT values and noise of left atrium and various branches of the pulmonary veins (upper left, lower left, upper right, and lower right). Statistical software was used for the two groups of images to analyze the carrier noise ratio (CNR), signal noise ratio (SNR), blinded scores, computed tomography dose index (CTDIvol), and dose-length product (DLP) of the left atrium and pulmonary vein. ResultsCNR and SNR of the left atrium and various pulmonary veins between the two groups had no significant differences (P>0.05) . Blinded scores between the two groups were not significantly different (P>0.05) . CTDIvol in group A and group B was respectively (2.92±0.38) and (20.15±12.09) mGy, with a significant difference (t=?7.803, P<0.001) . DLP of group A was (59.30±6.67) mGy·cm, significantly lower than that in group B [(334.43±216.71) mGy·cm] (t=?6.591, P<0.001) . Flash-efficient radiation dose was (0.83±0.94) mSv in group A, far below that in group B [(4.53±3.03) msv], and the difference was statistically significant (t=?6.684, P<0.001) . ConclusionsDual-source CT Flash technology applied in 3D cardiac scanning can reduce radiation dose as well as meet the needs of image diagnosis.
The Monte Carlo N-Particle (MCNP) is often used to calculate the radiation dose during computed tomography (CT) scans. However, the physical calculation process of the model is complicated, the input file structure of the program is complex, and the three-dimensional (3D) display of the geometric model is not supported, so that the researchers cannot establish an accurate CT radiation system model, which affects the accuracy of the dose calculation results. Aiming at these two problems, this study designed a software that visualized CT modeling and automatically generated input files. In terms of model calculation, the theoretical basis was based on the integration of CT modeling improvement schemes of major researchers. For 3D model visualization, LabVIEW was used as the new development platform, constructive solid geometry (CSG) was used as the algorithm principle, and the introduction of editing of MCNP input files was used to visualize CT geometry modeling. Compared with a CT model established by a recent study, the root mean square error between the results simulated by this visual CT modeling software and the actual measurement was smaller. In conclusion, the proposed CT visualization modeling software can not only help researchers to obtain an accurate CT radiation system model, but also provide a new research idea for the geometric modeling visualization method of MCNP.
ObjectiveTo study the examinees' cognitive level of the X-ray radiation, and to provide references for popularizing radiation protection knowledge. MethodWe chose patients who were checked in the Department of Radiology in our hospital between August 30 and October 29, 2013 as our study subjects, and carried out investigation by anonymous questionnaires. The investigation content included the respondents' basic information, ways to obtain the radiation knowledge, how well the patients knew about the fundamental radiation knowledge and their attitudes towards radiological examination and so on. A total of 2 315 patients were investigated, and 2 315 questionnaires were issued. Finally all questionnaires were retreated. ResultsAmong the 2 315 patients, 2026 (87.52%) knew the radiation symbol and 1 821 (78.66%) knew that X-ray radiation was harmful to the human body. Different age, gender, occupation, educational level and previous X-ray examination made significant differences in the fundamental knowledge on X-ray (P<0.05) . Attitudes towards X-ray examination was significantly different due to different age, occupation, and educational level (P<0.05) . Most examinees got the X-ray fundamental radiation knowledge from the publicity and medical staff in hospitals. ConclusionsTo make the examinees keep right attitudes and behaviors in radiographic examination, further effective methods of popularizing the basic knowledge of radiation should be carried out. Those publicity and medical staff in hospitals are the main force in the popularization of radiation knowledge.
ObjectiveTo evaluate the value of 70 kV and sonogram-affirmed iterative reconstruction technique in CT examination for children with congenital heart disease. MethodsThirty children with congenital heart disease who underwent CT scan between January and September 2014 were included in this study. According to the different tube voltage, they were randomly divided into group A (80 kV) and group B (70 kV), with fifteen in each. All the children were scanned on a dual-source-CT (Siemens Definition Flash). Group A used filtered back projection reconstruction. Group B used sonogram-affirmed iterative reconstruction. We measured and calculated the pulmonary artery signal-to-noise ratio at the level of main pulmonary artery window, the signal-to-noise ratio of the ascending aorta, noise ratio contrast between the pulmonary artery and erector spinae and between the ascending aorta and erector spinae. The image quality for congenital heart disease was assessed by two senior radiologists. The measurement of radiation dose included effective dose (ED), volume CT dose index (CTDIvol) and dose length product (DLP). ResultsThere were no significant differences between group A and B in terms of pulmonary artery signal-to-noise ratio (14.54±3.77, 11.23±2.52), the signal-to-noise ratio of the ascending aorta (14.76±3.41, 12.31±3.47), the noise ratio contrast between pulmonary artery and erector spinae (12.04±3.96, 9.18±3.76) and between the ascending aorta and erector spinae (12.47±4.59, 9.77±4.41) (P > 0.05). There was significant difference between group A and group B in CTDIvol[(0.53±0.09), (0.38±0.03) mGy], DLP[(12.93±1.79), (6.67±0.72) mGy·cm], and ED[(0.34±0.05), (0.17±0.02) mSv] (P < 0.05). ConclusionThe application of 70 kV and sonogram-affirmed iterative reconstruction technique in CT examination for children with congenital heart disease can significantly reduce the radiation dose without any influence on image quality.