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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.
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ObjectiveTo reduce the effective dose and maintain the image quality by adjusting the image processing parameters in the lumbar spine examinations.Methods This study investigated the influence of image processing parameters on image quality of Philips DR system by evaluating image quality of CDRAD 2.0 phantom.The parameters include detail contrast enhancement,noise compensation,unsharp masking and unsharp masking kernel.The entrance surface dose of phantom was measured by solidose meter.A synthetical parameters optimization project was proposed by analyzing the results of the investigation.This project was also testified by phantoms.ResultsImportant effects were the main effects of DCE,unsharp masking and kernel at the clinically used tube potential of 70 kVp( F =91.45,373.79,429.88,P ＜ 0.05).These effects indicated an increase of the 1QF about 20 units with increasing unsharp masking,while an increase of DCE and kernel led to decrease of IQF about 10 and 21 units.When the tube potential was increased to 85 kV,keeping the settings of the process parameters unchanged,the IQF increased.The results showed statically significant difference ( t =5.31,P ＜ 0.05 ).ConclusionIt is possible to lower the effective dose to the patient by the use of a higher tube potential and maintain a good image quality,and it will have little influence on clinic diagnosis through the most optimal setting of the process parameters.
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Objective: Introduce Internet and wireless communication technology into radiology image remote diagnosis system, develop a new system combined with PACS. Material and Methods: Used ASP.NET technology under VS. NET2005, and used JAVA to develop the image APPLET, Web server used 11S5.0, database used Microsoft SQL Server. Also need a SMS Modern to send message online. Results: Offer two ways to access medical image remote diagnosis system: Interact and wireless networks. Wherever a doctor he is, as long as has a computer or mobile phones can be connected to Interact or wireless network, can login diagnosis system, browse the patients' images, do some image processing, and also can send reports. Conclusions: The system can be put into practice, lifting the restrictions in time and place of remote diagnosis system, it try in full-development of telemedicine. Although at present reports of this form does not have legal effectiveness, this paper provided a new idea for development of medical image remote diagnosis system.
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Objective The imaging quality and irradiation dose were compared between scatter filtering template performance and conventional grid in digital radiography.MethodsImages of contrast-detail phantom and ROC statistic phantom corrected with scatter filtering template method and grid were obtained,respectively.The image quality factors(IQF)and sihnal detection probability values(Pdet)and imaging dose were analyzed by ANOVA,SNK and t test statistics for the two methods of scatter removing.ResultsThe difference of IQF and signal detection probability of images corrected by scatter filtering template technique and conventional snd Was statistically significant.ConclusionsIn digital radiography,STFF can effectively filter scattering,improve image quality without increasing the exposure.With the same image quality.it can reduce the entrance surface dose by about 30% than filter grid.In order to effectively filter scattering,improve the quality of X-ray image,and reduce the patient dose.STFF is an alternative method.
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ObjectiveTo analyze the effects of three different display devices on the interpretation of imaging data in medieal imaging system.MethodsThe luminance-meter L100 and the test patterns provided by the American Association of Physicists in Medicine(AAPM)were used to assess the performance of three display devices(the spherical,flat panel and liquid crystal display devices).The corresponding luminance response was compared with the reference criteria provided by AAPM Task Group 18(AAPM TG18).DR chest photography was taken on CDRAD2.0 contrast-detail phantom using the following experimental parameters:100 mA,80 kVp,and the exposure times for 6,10,12,and 16 ms.After each exposure,the surface dose of phantom was recorded and the image quality factor(IQF)was calculated.Statistical analysis of IQF was performed using ANOVA. ResultsThe maximum luminance values in the spherical,flat panel and liquid crystal display devices were 170,59 and 231 cd/m2 and the luminance ratio was 257, 99 and 350 respectively.There was a significant difference in the IQF bewteen the liquid crystal display device and other two display devices.Conclusion The liquid crystal display device has the better image quality.
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Objective To determine the urine parameters,body temperature and main organ coefficient of Fujian rabbits.Methods In this experiment,we selected twenty healthy Fujian rabbits with weight of about 2.5kg.Both male and female rabbits were ten.Before experiment,the rabbits drunk water freely.We collected fresh urine before breeding in the morning,and then determined the ten items urine parameters soon.Under the room temperature,we used electricity thermometer into the rabbits' rectum to determine the body temperature.Being fasting for 12h,the rabbits were anesthetized by 3% pentobarbital sodium,and then were put to death after bloodletting.The dissection took various internal organs immediately.The clean organs were weighed by electronic analytical balance.Results The results showed that the majority of the urine was yellow opacity,and the ten items urine parameters between male and female had no significant difference.The average body temperature of Fujian rabbits was 39.67℃ above other ones.There was no significant difference in main organ coefficient between male and female expect the lung and spleen.Conclusion In a word,it was objective to determine the body temperature,urine parameters,mainly organ coefficient of Fujian rabbits which were fed in conventional environment.It is valuable for the appliation of Fujian rabbits in life science sphere.
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Objective To get the maximum information from computed radiography (CR) output images by changing post-processing parameters. Methods Six experimental photos of polypropylene balls of 2.0 mm in diameter were taken by means of one time X-ray exposing on an imaging plate (IP) with different post-processing parameters including rotation amount (GA), gray gradation type (GT), rotation center (GC), shifting amount (GS), frequency rank (RN), frequency type (RT), and degree of enhancement (RE). 6 photos were viewed by three students and one radiologist on a 6 000 lx illuminance viewbox. Receiver operating characteristic (ROC) curves were made by means of 5-value-differentiation method. Results The largest mean area value (Az) below ROC curves of a low contrast experimental photo with post-processing parameters GA=1.0,GT=A, GC=1.6, GS=0.3, RN=4.0, RT=R and RE=3.0 was 0.96, and the maximum information was obtained. The smallest mean area value (Az) was 0.78 with changed post-processing parameters GA=0.8, GS=-0.2 and RE=0.5 while other parameters were not changed. The minimum information was obtained from this photo. Conclusion In order to get the maximum information from a CR output image, the post-processing parameters should be suitably selected.
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Objective To study the effect of image processing on overall Wiener spectrum (WS) in a computed radiography system. Methods Imaging plate was exposed using conventional X-ray equipment. Overall WS sampling films were made by changing 3 parameters of spatial frequency processing, including frequency rang(RN), frequency type(RT), and degree of enhancement(RE), and by changing 1 of 4 parameters of gradation processing(rotation amount,GA).WS values were calculated by scanning on micro-densimeter for every film proceeded as discrete signal using fast Fourier transform. Results (1) The WS value of subscan direction was 7.26?10 -5 mm 2 when the spatial frequency was 1.0 LP/mm, it was 1.57 times larger than that of scan direction. The WS had peaks under high spatial frequency at sunscan direction. (2) The WS value of RN with 0 at scan direction was 7.90?10 -5 mm 2 when the spatial frequency was 1.0 LP/mm, it was 1.70 times larger than that of RN with 5, and 3.30 times larger than that of RN with 9. (3) The WS value of RE with 1.5 at scan direction was 1.05?10 -4 mm 2when the spatial frequency was 1.0 LP/mm, it was 2.27 times larger than that of RE with 1.0, and 2.92 times larger than that of RE with 0.5. (4) The WS value of GA with 1.5 at scan direction was 1.25?10 -4 mm 2 when the spatial frequency is 1.0 LP/mm, it was 2.70 times larger than that of GA with 0.8. (5) The WS value of RT with T at subscan direction was 9.80?10 -5 mm 2 when the spatial frequency was 1.0 LP/mm, it was 1.02 times larger than that of RT with F, and 1.35 times larger than that of RT with R, and also 1.55 times larger than that of RT with P. Conclusions RN, RE, and GA contributed strongly to Wiener spectra, but the contribution of RT was small. When processing the clinical images, adequate processing parameters should be chosen to reduce the image noise, so as to meet the clinical diagnostic need.
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Objective To test the overall characteristic curve on a computed radiography system. Methods Imaging plate was exposed by scale-time expose using conventional X-ray equipment. It was processed by CR system. Density of different optical density wedge on CR film was measured by using densimeter. Then, characteristic curve was plotted. Results (1) Overall characteristic curve of CR system was affected by gradation processing. (2) Average gradient of overall characteristic curve was 1.98, 3.10, and 3.75 when GA was 0.8,1.4, and 2.4. (3) Overall characteristic curve rotated around rotation center when rotation amount was changed. Conclusion According to the diagnostic purpose and different body position, rotation amount can be selected, and different contrast imaging can be acquired.