Clinical application of the optimized X-ray parameter model through analysis of disease risk and image quality when combining the ion chamber of automatic exposure control of digital radiography.

OBJECTIVE: To present an optimized examination model by analyzing the risk of disease and image quality according to the combination of the ion chamber of automatic exposure control (AEC) with digital radiography (DR). METHODS: The X-ray quality was analyzed by first calculating the percentage average error (PAE) of DR. After that, when using AEC, the combination of the ion chambers was the same as the left and centre and right, right and centre, left and centre, centre, right, and left, for a total of six. Accordingly, the entrance surface dose (ESD), risk of disease, and image quality were evaluated. ESD was obtained by attaching a semiconductor dosimeter to the L4 level of the lumbar spine, and then irradiating X-rays to dosimeter centre through average and standard deviation of radiation dose. The calculated ESD was input into the PCXMC 2.0 programme to evaluate disease risk caused by radiation. Meanwhile, image quality according to chamber combination was quantified as the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) through Image J. RESULTS: X-ray quality of DR used in the experiment was within the normal range of±10. ESD of six ion chamber combinations was 1.363mGy, 0.964mGy, 0.946mGy, 0.866mGy, 0.748mGy, 0.726mGy for lumbar anteroposterior (AP), and the lumbar lateral values were 1.126mGy, 0.209mGy, 0.830mGy, 0.662mGy, 0.111mGy, and 0.250mGy, respectively. Meanwhile, disease risk analyzed through PCXMC 2.0 was bone marrow, colon, liver, lung, stomach, urinary and other tissue cancer, and disease risk showed a tendency to increase in proportion to ESD. SNR and CNR recorded the lowest values when three chambers were combined and did not show proportionality with dose, while showed the highest values when two chambers were combined. CONCLUSION: In this study, combination of three ion chambers showed the highest disease risk and lowest image quality. Using one ion chamber showed the lowest disease risk, but lower image quality than two ion chambers. Therefore, if considering all above factors, combination of two ion chambers can optimally maintain the disease risk and image quality. Thus, it is considered an optimal X-ray examination parameter.

High-energy high-dose microfocus X-ray computed tomography driven by high-average-current photo-injector.

High-energy, high-dose, microfocus X-ray computed tomography (HHM CT) is one of the most effective methods for high-resolution X-ray radiography inspection of high-density samples with fine structures. Minimizing the effective focal spot size of the X-ray source can significantly improve the spatial resolution and the quality of the sample images, which is critical and important for the performance of HHM CT. The objective of this study is to present a 9 MeV HHM CT prototype based on a high-average-current photo-injector in which X-rays with about 70µm focal spot size are produced via using tightly focused electron beams with 65/66µm beam size to hit an optimized tungsten target. In digital radiography (DR) experiment using this HHM CT, clear imaging of a standard 0.1 mm lead DR resolution phantom reveals a resolution of 6 lp/mm (line pairs per mm), while a 5 lp/mm resolution is obtained in CT mode using another resolution phantom made of 10 mm ferrum. Moreover, comparing with the common CT systems, a better turbine blade prototype image was obtained with this HHM CT system, which also indicates the promising application potentials of HHM CT in non-destructive inspection or testing for high-density fine-structure samples.

Quantitative Analysis Methods Using Histogram and Entropy for Detector Performance Evaluation According to the Sensitivity Change of the Automatic Exposure Control in Digital Radiography.

The purpose of this study is to evaluate detector performance using histogram and entropy analysis according to the sensitivity change of the automatic exposure control (AEC). The experiment was performed as follows: The sensitivity of the detector was analyzed through a normalized histogram with sensitivities of S200, S400, S800, and S1000 of the AEC; the entropy of the image was then analyzed, and the signal volume of the detector was evaluated according to the sensitivity change. As the sensitivity of the AEC was increased from S200 to S1000, the histogram showed underflow, quantization separation, and dynamic range discrepancy. In addition, entropy showed a decrease as sensitivity was set higher; in particular, entropy degradation was more prominent at sensitivities above S800. Through the histogram and entropy analysis, it was concluded that the detector does not reproduce the sensitivity and signal volume accurately when the sensitivity of the AEC is set high in performance evaluation.

[Application of Pareto Analysis in Studying DR High Fault Rate].

OBJECTIVE: To explore the effect of Pareto analysis on the investigation of DR (Digital Radiography) high fault rate. METHODS: The quality control team was established to analyze the causes of DR high fault rate by using the fault statistics of eight DR in our hospital for nearly three years,and to formulate and implement countermeasures,then compare them with the data after rectification. RESULTS: After three months of implementation,the number of DR faults in our hospital decreased from 130 times/quarter to 47 times/quarter,a year-on-year drop was 63.8%.Among them,the number of console faults decreased from 105 times/quarter to 25 times/quarter,a year-on-year drop was 76.2%,close to 80%. CONCLUSIONS: Pareto analysis is effective in reducing DR fault rate and is worthy of being promoted to other medical devices.

Application of Pareto Analysis in Studying DR High Fault Rate / 中国医疗器械杂志

OBJECTIVE@#To explore the effect of Pareto analysis on the investigation of DR (Digital Radiography) high fault rate.@*METHODS@#The quality control team was established to analyze the causes of DR high fault rate by using the fault statistics of eight DR in our hospital for nearly three years,and to formulate and implement countermeasures,then compare them with the data after rectification.@*RESULTS@#After three months of implementation,the number of DR faults in our hospital decreased from 130 times/quarter to 47 times/quarter,a year-on-year drop was 63.8%.Among them,the number of console faults decreased from 105 times/quarter to 25 times/quarter,a year-on-year drop was 76.2%,close to 80%.@*CONCLUSIONS@#Pareto analysis is effective in reducing DR fault rate and is worthy of being promoted to other medical devices.

Study on public dose burden in Suzhou from medical exposure in X-ray digital radiography and computed tomography / 中华放射医学与防护杂志

Objective To estimate the effective dose burden to the public in Suzhoui induced by medical exposure from computed tomography (CT) and digital radiography (DR).Methods Twenty-seven hospitals were selected by stratified random sampling.The application information was colleted from picture archiving and communication system (PACS) and radiology information system (RIS).For DR,DAP was measured by the dose-area product meter in different body parts,then the effective dose values were calculated by the DAP.For CT,effective dose was estimated by measuring CT dose index weighted (CTDIw) and scanning parameters in different parts of the body.The public dose burden caused by DR and CT medical exposure in Suzhou was estimated according to the scanning time and effective dose to each part.Results The effective dose due to DR examination was abdomen AP 0.565 mSv,pelvis AP 0.280 mSv,skull LAT 0.016 mSv,skull AP 0.012 mSy,chest LAT 0.111 mSv,chest AP 0.060 mSv,thoracic spine LAT 0.100 mSv,thoracic spine AP 0.102 mSv,lumbar spine LAT 0.307 mSv and lumbar spine AP 0.152 mSv,respectively.The effective doses from CT scanning were 1.33 mSv for head,5.75 mSv for thorax and 7.31 mSv for abdomen,respectively.The annual collective effective dose in Suzhou in 2017 from DR exposures and CT scans was 9 593.07 man · Sv,and the average annual effective dose was 0.898 mSv.Conclusions The contribution of CT medical radiation to the public dose is much greater than that of DR.Controlling the frequency of medical exposure and single scan dose is an effective way to reduce the public dose burden.The public dose burden from DR and CT medical exposure in Suzhou is at a high level and attention needs to be paid by relevant health administrative departments.

Study on public dose burden in Suzhou from medical exposure in X-ray digital radiography and computed tomography / 中华放射医学与防护杂志

Objective@#To estimate the effective dose burden to the public in Suzhoui induced by medical exposure from computed tomography (CT) and digital radiography (DR).@*Methods@#Twenty-seven hospitals were selected by stratified random sampling. The application information was colleted from picture archiving and communication system (PACS) and radiology information system (RIS). For DR, DAP was measured by the dose-area product meter in different body parts, then the effective dose values were calculated by the DAP. For CT, effective dose was estimated by measuring CT dose index weighted (CTDIw) and scanning parameters in different parts of the body. The public dose burden caused by DR and CT medical exposure in Suzhou was estimated according to the scanning time and effective dose to each part.@*Results@#The effective dose due to DR examination was abdomen AP 0.565 mSv, pelvis AP 0.280 mSv, skull LAT 0.016 mSv, skull AP 0.012 mSv, chest LAT 0.111 mSv, chest AP 0.060 mSv, thoracic spine LAT 0.100 mSv, thoracic spine AP 0.102 mSv, lumbar spine LAT 0.307 mSv and lumbar spine AP 0.152 mSv, respectively. The effective doses from CT scanning were 1.33 mSv for head, 5.75 mSv for thorax and 7.31 mSv for abdomen, respectively. The annual collective effective dose in Suzhou in 2017 from DR exposures and CT scans was 9 593.07 man·Sv, and the average annual effective dose was 0.898 mSv.@*Conclusions@#The contribution of CT medical radiation to the public dose is much greater than that of DR. Controlling the frequency of medical exposure and single scan dose is an effective way to reduce the public dose burden. The public dose burden from DR and CT medical exposure in Suzhou is at a high level and attention needs to be paid by relevant health administrative departments.

Investigation and analysis on entrance surface dose of patients in radiography procedures in China / 中华放射医学与防护杂志

Objective To investigate the entrance surface dose to the examined patients in radiography using digital and screen-film system in hospitals at different levels in 15 provinces and municipalities in China,in order to provide data for developing diagnostic reference level of radiography suitable for our national physical characteristics.Methods According to the requirements of the Technical Study on Medical Radiation Hazard Assessment and Control,the examined patients aged 20-70 years were selected,with body weight ranging from 55 to 80 kg for male and 50 to 70 kg for female.TLDs were used to measure the entrance surface dose to adult patients in radiography.No less than 10 examined patients were required at each body position,with examined locations including head (PA,LAT),chest (PA,LAT),abdomen (AP),pelvis (AP),lumbar (AP,LAT),and thoracic vertebra (AP,LAT).Results A total of 19 975 individuals undergoing radiography and 1 813 radiographic equipment of different types including screen-film radiography,computed radiography (CR) and digital radiography (DR),were investigated in 342 hospitals in 15 provinces and municipalities throughout the country.For these three types of equipment,the average entrance surface dose to the examined were 1.75,1.9,and 1.15 mGy in head (PA),1.69,1.46and 1.03 mGy in head (LAT),0.75,0.65 and 0.36 mGy in chest (PA),1.81,1.26 and 0.88 mGy in chest (LAT),4.37,3.77 and 2.15 mGy in abdomen (AP),3.73,3.56 and 2.75 mGy in pelvis (AP),5.49,5.84 and 4.17 mGy in lumbar (AP),12.01,9.37 and 6.82 mGy in lumbar (LAT),4.53,3.65 and 2.49 mGy in thoracic vertebra (AP),and 6.91,6.43 and 4.15 Gy in thoracic vertebra (LAT).Conclusions Entrance surface dose caused by radiography examination varies dependent on different exposure locations.Entrance surface doses caused by digital radiography are all lower than by screen-film radiography;those caused by digital radiography are lower than by computed radiography,except for thoracic vertebra (AP).In all examinations,no difference of statistical significance is found between CR and screen-film radiography in entrance surface dose.

Statistics and analysis of detection data for radioactivity performance of DR / 中国医学装备

Objective: To analyze and research detection data of radioactivity performance of digital radiography (DR) equipment so as to provide reference for purchasing DR equipment in hospital. Methods: Through collected the analysis results of detection data of quality control of 153 DR equipment of third level 1st class hospital, third level 2nd class hospital and county level hospital of Yunnan province. The comparison analysis about these DR equipments depended on the hospital type, nationality of equipment and duration of service. Results: There were 50 DR equipment and 103 DR equipments in the third level 1st class hospital and the third level 2nd class hospital, respectively. And in the third level 1st class hospital, there was 79.17% of DR equipments was imported equipment, while it was 51.45% in the third level 2nd class hospital. Besides, the duration of service of the most of DR equipments was 0-4yeras in the third level 2nd class hospital, while it was 5-7 years in the third level 1st class hospital. Conclusion: Most of the DR equipments in the third level 1st hospitals are imported equipment, and their duration of service were longer. On the other hand, in the comparison between imported equipment and domestic equipment, there are a certainly gap in quality stability, reliability and other aspects.

Reduced radiation dose and improved image quality using a mini mobile digital imaging system in a neonatal intensive care unit.

This study was aimed to assess the radiation dose and image quality of a mini-mobile digital imaging (mini-DI) system for neonatal chest radiography and compared to conventional digital radiography (DR). A total of 64 neonates were examined and anatomical landmarks were assessed. The entrance surface dose of mini DI and conventional DR was 26.64±0.15 µGy and 49.11±1.46 µGy, respectively (p<0.001). The mean SNR values for mini-DI and DR were 233.2±5.1 and 31.6±1.2, and 10% MTF values were 131 and 161µm. A newly developed mini-DI is capable of preserving the diagnostic information with dose reduction in neonates under intensive care.

A robust general phase retrieval method for medical applications.

From medical imaging perspective the robustness of a phase retrieval method is of critical importance. In this presentation we compare the robustness of two general phase retrieval methods, namely the transport of intensity equation inversion (TIE-inversion) method and the attenuation partition based (AP-based) method. We showed that the TIE-inversion method, regardless if being assisted with the Tikhonov regularization, failed to retrieve the phase maps in two experimental studies. The failure exposes this method's weakness as being unstable against the noise. In contrast, the sample phase maps are retrieved successfully by using the AP-based method. The stark performance differences of the two methods are rooted in their different techniques dealing with the singularity problem. This comparison shows that the robust AP-based phase retrieval method will be superior to the TIE-inversion method for medical imaging applications where radiation doses are stringently limited.

Retrospective evaluation of exposure index (EI) values from plain radiographs reveals important considerations for quality improvement.

INTRODUCTION: Following X-ray exposure, radiographers receive immediate feedback on detector exposure in the form of the exposure index (EI). PURPOSE: To identify whether radiographers are meeting manufacturer-recommended EI (MREI) ranges for routine chest, abdomen and pelvis X-ray examinations under a variety of conditions and to examine factors affecting the EI. METHODS: Data on 5000 adult X-ray examinations including the following variables were collected: examination parameters, EI values, patient gender, date of birth, date and time of examination, grid usage and the presence of implant or prosthesis. Descriptive statistics were used to summarize each data set and the Mann-Whitney U test was used to determine significant differences, with P < 0.05 indicating significance for all tests. RESULTS: Most examinations demonstrated EI values that were outside the MREI ranges, with significantly higher median EI values recorded for female patient radiographs than those for male patients for all manufacturers, indicating higher detector exposures for all units except for Philips digital radiography (DR), where increased EI values indicate lower exposure (P = 0.01). Median EI values for out of hours radiography were also significantly higher compared with normal working hours for all technologies (P ≤ 0.02). Significantly higher median EI values were demonstrated for Philips DR chest X-rays without as compared to those with the employment of a grid (P = 0.03), while significantly lower median EI values were recorded for Carestream Health computed radiography (CR) chest X-rays when an implant or prosthesis was present (P = 0.02). CONCLUSIONS: Non-adherence to MREIs has been demonstrated with EI value discrepancies being dependent on patient gender, time/day of exposure, grid usage and the presence of an implant or prosthesis. Retrospective evaluation of EI databases is a valuable tool to assess the need of quality improvement in routine DR.

Application value of computed radiography energy subtraction in detecting pulmonary soft-tissue:comparison with direct digital radiography / 中华放射医学与防护杂志

Objective To compare the efficiency of computed radiography energy subtraction (ES-CR) with direct digital radiography (DR) in detecting the pulmonary soft-tissue signals.Methods The adult chest phantom including TRG was imaged by ES-CR and DR separately and was estimated by 6 radiologists with 5-value-differentiation method. ROC was used to analyze the performance of two systems. Images of DR and ES-CR of 28 patients with small lung cancer were diagnosed by 3 radiologists. Results The area under the ROC curves was 0. 727 in ES-CR and 0.827 in DR (Z= 2.96,P ＜ 0. 05). 28 small lung cancer patients were significantly different between two systems (x2 = 5.14,P ＜0. 05). Conclusions The true positive proportion of DR might be higher than that of ES-CR. ES-CR is inferior to DR in detecting pulmonary soft-tissue signals.

Discussion on application value of CR and DR / 医疗卫生装备

According to the comparison of CR and DR in such aspects as principle analysis,main parameters,software operation capability and development prospects,along with our experience,it is concluded that CR is now fit for the middle and small hospitals as an expedient intergrading digital image equipment,while for the hospitals with workload of over 100 persons per day,DR should be the primary digital image equipment and CR should work as auxililiary digital image equipment.

Application of the Mobile DR System in Large-scale Physical / 医疗卫生装备

Objective To discuss the application value of the mobile DR in large-scale physical examination. Methods Compared each 500 chest images that collected for the physical examination by the mobile DR, direct digital radiography(DR), then did another comparison about each 300 chest images of mobile DR and phnendoskiascope, recorded them by no displayed, displayed and limpid-displayed. Results The resolution of images collected by the mobile DR was comparative with the ones collected by direct digital radiography, better than phnendoskiascope in showing details. Conclusion The mobile DR images have a good resolution ratio as DR images have, meanwhile, this machine is easy to be taken and removed Examination while DR could not, and therefore the machine can do large-scale physical whatever inside or outside.