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Objective To analyze the hemodynamic parameters of anomalous origin of the right coronary artery from the left coronary artery sinus (AORL) based on computational fluid dynamics (CFD), so as to make an evaluation of the disease. Methods A normal right coronary artery (RCA) case and an AORL case were selected. Two models were reconstructed in Mimics software and imported into ANSYS CFX software for hemodynamics simulation. The hemodynamics of normal RCA model and AORL model were compared. Results AORL model had a smaller volume flow (9.35 cm3/s), which might lead to insufficient blood supply downstream of the RCA; the pressure at the acute corner of AORL model (13.78 kPa) was lower than normal RCA model (14.9 kPa); the wall shear stress (WSS) of AORL model (12.83 Pa) was larger than that of normal RCA model (9.74 Pa); the total deformation of AORL model was relatively large. Conclusions The entrance velocity and pressure of AORL were lower than those of normal RCA, which might lead to ischemic symptoms. The research findings are of theoretical significance for the effective evaluation of ischemia and other diseases in clinic.
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Objective To establish a method based on 3D printing radiology equivalent phantom for individual radiotherapy dose verification,and to offer an assurance for the safety of 3D conformal radiotherapy.Methods Two patients' CT data was collected,reconstructing the first patient's skull and brain tissue to generate a skull-brain phantom for the purpose of testing the equivalent material.The second patient's data was used for whole head tissue reconstruction to produce a head phantom with equivalent material.By inserting ionization chamber dosimeters to target region for radiotherapy program,equivalent phantom dose distribution of lesions location was obtained in order to verify and calibrate the actual radiation treatment planning for patients.Results DR,CT images of the phantoms revealed that the difference of X-ray gray value between brain skull phantom and patient's skull was 13 721,CT value difference between equivalent tissue of brain skull phantom and that part of the patient was 35-40 HU,and CT difference between head phantom temporalis and that of the patient tissue was 18-28 HU.The imaging data indicated that the radiation equivalence of 3D printing phantom was similar to that of human body tissue,and the equivalent dose distribution accorded well with the normal range of treatment.The dose verification of phantom model can effectively improve the accuracy of the radiotherapy system.Conclusions The personalized radiotherapy phantom which based on the 3D printing and tissue equivalent technology is suitable for personalized radiation therapy validation.With advantages of easy accessibility,highly-personalized degree and high precision,this technology provides a reliable and safe way for radiation therapy.
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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.
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Objective To explore the relationship between image quality and different exposure intensity of digital radiography(DR).Methods Using a contrast-detail phantom Cdrad 2.0,observers evaluated images on the monitots when exposure parameters were 90 kV and mAs ranged from 0.5 to 16.0 mAs.Then calculate image quality figure(IQF),and ANOVA was used to analyze the difference of IQF under different radiation dose in 8 subjects.Results (1)When exposure parameters were 90 kV and mAs altered from 0.5 to 8.0 mAs.the IQF observed on the monitor was reduced,and the minimal value was 38.54±2.82.When mAs changing from 8.0 to 16.0 mAs.IQF observed on the monitor was increased,and the maximum was 44.33±2.35.(2)Under the different exposure condition,the difference of IQF values were statistically significant(F=60.35,P＜0.01).Conclusions With the increased exposure intensity,the image quality on monitor increased.When mAs was 8.0 mAs,image quality was the optimum When mAs was more than 8.0 mAs,the image quality on monitor reduced.
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By software and signal analysis,visualization of medical NMR signals becomes possible.The T1,T2 resonance frequency value reflecting human tissue characteristics,and the FID,echo wave as well as other curves reflecting the intensity of signals,can contribute a lot to the teaching of the applied analysis of clinical NMR and MRI principles.
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0. 05); lung field Az_1=0.6964, Az_2=0.7958, showing significant difference (?~2=4.9947, P
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Objective To study the influence of CRT brightness on image reading. Methods Both physical testing and compared viewing were used in the study. (1) Setting the CRT brightness at high and low grade (the blank brightness of CRT was 112 cd/m 2 and 82 cd/m 2, respectively). (2) 21 films with the density ranging from 0.27 to 2.71 were digitized by a scanner and displayed on the CRT. The brightness of CRT that varied with film density was measured by a bright meter, then the relation chart between CRT brightness and the film density was drawn. (3) Thirteen films on which there were many small and low contrast signals were viewed on CRT by three doctors. The tested data were calculated by statistics (? 2 test, the difference was significantly marked when P 0.05), but the signals viewed in the lung were 87 and 29, and the difference was significantly marked (? 2=53.73, P