虚拟仿真技术的不断成熟,使我们逐渐认识到了它在教育中所发挥的作用.医学影像学学生在传统的教学模式当中,面临着课堂枯燥,实验室仪器设备落后且缺乏等种种问题,尤其是在学习X线球管过程,无法细致直观地观察到X光线及成像过程.而正是虚拟仿真技术的出现,成为了解决以上问题的关键.通过将虚拟仿真技术与X线球管结合,不仅可以使学生更好地掌握对这方面知识,而且还可以锻炼学生们的自我钻研与创新能力,最重要的是这种技术对资金投入的要求不大,十分方便高效.尽管这种技术现在还没有完全普及,但不难想象,在未来的几年里,我们一定会在学生的课堂中,见识到该技术的风采.

为了比较乳腺恶性和良性病变在数字化乳腺X线图像中的影像学特征,在美国南佛罗里达大学的数字化乳腺X线图像数据库中随机选取466名病人的数字化乳房X线图像.在乳腺成像领域有着5年以上经验的放射学专家对乳腺恶性和良性病变的影像学特征进行比较.两样本t检验表明恶性乳腺病变在1 cm×1 cm区域内的钙化数量明显高于良性乳腺病变(P＜0.001).同时,恶性乳腺病变中的不规则或有毛刺状边缘的分叶状肿块的比例明显高于良性乳腺病变(P＜0.000 1).而不规则或边缘局限的分叶状肿块的比较结果却截然相反.此外,良性乳腺病变中边缘局限的椭圆或圆形肿块的比例明显高于恶性乳腺病变(P=0.001).然而,当前研究数据表明只有恶性乳腺病变表现出边缘局限的椭圆或圆形肿块.恶性乳腺病变的结构扭曲率(5.2％)略高于良性乳腺病变(1.7％)(P=0.042).其他的影像学特征并没有明显差异.本研究表明恶性乳腺病变的主要影像学特征为有毛刺状边缘或者结构扭曲的肿块、钙化集中(在1 cm×1 cm区域内的钙化数量超过21个),而良性乳腺病变的主要影像学特征为边缘局限的肿块.

Objective To explore the value of multi‐slice spiral CT in diagnosis of nodular goiter .Methods Clinical data of the patients with nodular goiter of 39 cases confirmed by surgery pathology were retrospectively analyzed and compared pathologic results with CT manifestations .Results CT showed isolated nodule type in 21 cases and the diagnosis accord‐ance rate of CT was 85 .7% (18/21) ,CT showed multiple nodular type in 13 cases and the diagnosis accordance rate of CT was 76 .9% (10/13) ,CT showed diffuse nodule type in 5 cases and the diagnosis accordance rate of CT was 60% (3/5) . Conclusion Multi‐slice spiral CT is helpful to the diagnosis and classification of nodular goiter .

Objective To investigate optimal radiation dose for digital radiography by researching the correlation between radiation dose and image quality of high kV chest radiography.Methods The kV of chest radiography was setted on 120 kV while mAs was changed.The chest radiography phantom and the contrast detail phantom CDRAD2.0 were exposed by DR with different mAs from 1 to 25 mAs.The entrance doses were measured for all exposures and the images were read independently by 5 observers on a higher resolution monitor of diagnosis work station.The image quality figure (IQF) was measured for each image.Comparison of the mean IQFs with different exposure doses were conducted in order to determined which was the optimal exposure condition for high kV radiography.The image quality of normal adult using different mAs,4 and 10 mAs for high KV chest radiography was compared.Results When the mAs was increased from 1 to 25 mAs,the entrance doses varied from 0.067 to 1.468 mGy.With the entrance doses increasing,the value of IQF was decreased (F =31.00,P ＜ 0.05).The values of IQF were statistically different between 1 and 4 mAs(F =15.3,P ＜0.05),and between 10 and 25 mAs(F =9.74,P ＜0.05).At 4 and 10 mAs with the entrance dose 0.250 and 0.606 mGy,the synthesis score of chest high kV radiography from two kinds of exposure dose was (24.8 ± 1.64),(25.8 ± 2.05),with no statistically significant difference.Conclusions For digital radiography,increasing radiation dose can improve image information.The optimal entrance dose of high kV chest radiography for standard body was about 0.250 mGy.

Pancreas is an important digestive organ in human body.Human healthy is threatened seriously by diseases of pancreas,especially pancreatic carcinoma.For this reason,it has a significant effect on treatment and cure to make an accurate and pristine diagnose.At present,CT is the chief examination method of pancreatic diseases.In recent years,high field magnetic resonance appeared and showed distinct superiority because of its sensitive signal change,multiple plane imaging,fat-suppression and fast dynamic enhancement imaging technology.This paper will review 3.0T MRI application on pancreas pathological changes.

Objective To study the relationship between the selection of tube tension in digitalchest radiograph and image quality.Methods When tube current was fixed at 4 mAs, the choice of X-ray tube voltage changed from 60 to 120 kV.CDRAD2.0 contrast details phantom and normal human chest were exposed by X-ray system with 7 kinds of tube voltage (the difference between tube voltage was 10 kV) ,and the X-ray incidental dose of phantom surface was measured.Five radiologists with 3 years working experience evaluated the image quality on monitor and calculated the image quality factor (IQF) and image reading score.Statistics analysis was then performed by using ANOVA test and t test.According to the results, the optimum tube voltage range was determined.Results (1) The incidental dose of phantom surface increased with the higher tube voltage.(2)When the tube voltage was changed from 60 kV to 120 kV, the IQF value observed in CDRAD2.0 phantom image on monitor was 75.0±10.4,57.1±6.4,52.7±2.5,47.9±4.5, 46.0±3.8,46.0±2.8,45.2±3.5 ,there was significant statistical differences between groups(F=19.10, P<0.01).(3)The integrated score of the chest image quality in the tube voltage 90 kV and 120 kV were 12.4±0.9 and 13.0±0.7, respectively, and there was no statistical difference between two groups(t= 1.500,P>0.05).Conclusions (1)With the increase of tube tension,the display capacity of display device gradually strengthened.When the tube tension exceeded 90 kV, the increase of image quality on monitor was not evident.(2) With proper radiation dose, the value of tube tension in digital X-ray chest photograph was about 90 kV.

Objective: Measure tube voltage of mid-frequency and industry-frequency X-ray machine: Analyzing the effect of tube voltage of mid-frequency and industry frequency X-ray machine to image quality by the evaluation of ROC curve.Methods:(1) Measuring tube voltage of mid-frequency and industry frequency X-ray machine by non-invasive Evaluator of Radiation Outputs and TGR statistic phantom for X-ray photograph of ALVIM Co.USA and organic glass module of 7cm thickness;(2) Under the test condition obtaining the same photo density(D=0.7±0.05),acquiring two genus X-ray photos in the different voltage(70kV,80kV,90kV);(3)Five observers read the six X-ray photos by two genus X-ray machine,estimate image in different signal diameter(Φ=1.4 mm,Φ=1.7 mm,Φ=2.0 mm),and calculate the probability of every signal,then draw ROC curve of the two machines.Results:(1) Tube voltage of mid-frequency X-ray machine is Smoother than industry frequency.(2) Five observers read the six X-ray photos by two genus X-ray machines.When the signal diameter less than and equal to 1.4mm,there is no marked difference between the probability of two diameter signal(t=0.750,P>0.05);While the signal diameter is 1.7mm and 2.0mm,there is marked difference between the probability of two diameter signal(t=2.525,P<0.05).Conclusion: Under the same testing condition,the area surrounding by ROC curve of mid-frequency X-ray machine is bigger than industry frequency,and the detecting capability to signal of mid-frequency X-ray machine is better than industry frequency.The image quality of mid-frequency X-ray machine is much better than industry frequency.