To explore the effect and experience of quality control circle(QCC) in quality control testing for CT scanners, the quality control circle group was set up to determine the theme of quality control circle, and the causes of the failure of the quality control testing for CT scanners were analyzed, then the corresponding corrective measures were formulated and carried out. After the activity of the quality control circle, the qualified rate of CT quality control testing in the second level 2nd Class of public hospitals and private hospitals in Shanghai increased from 40.6% to 86.1%. By conducting quality control circle activities, we found the problems existed in the quality control testing of CT scanners, and put forward many corresponding corrective measures and solutions which finally improved the qualified rate of CT quality control testing.
China ; Quality Control ; Tomography Scanners, X-Ray Computed ; standards ; Tomography, X-Ray Computed

OBJECTIVE: The purpose of this study was to evaluate any improvement in the quality of abdominal CTs after the utilization of the nationally based accreditation program. MATERIALS AND METHODS: Approval was obtained from the Institutional Review Board, and informed consent was waived. We retrospectively analyzed 1,011 outside abdominal CTs, from 2003 to 2007. We evaluated images using a fill-up sheet form of the national accreditation program, and subjectively by grading for the overall CT image quality. CT scans were divided into two categories according to time periods; before and after the implementation of the accreditation program. We compared CT scans between two periods according to parameters pertaining to the evaluation of images. We determined whether there was a correlation between the results of a subjective assessment of the image quality and the evaluation scores of the clinical image. RESULTS: The following parameters were significantly different after the implementation of the accreditation program: identifying data, display parameters, scan length, spatial and contrast resolution, window width and level, optimal contrast enhancement, slice thickness, and total score. The remaining parameters were not significantly different between scans obtained from the two different periods: scan parameters, film quality, and artifacts. CONCLUSION: After performing the CT accreditation program, the quality of the outside abdominal CTs show marked improvement, especially for the parameters related to the scanning protocol.
*Accreditation ; Humans ; *Quality Improvement ; Radiography, Abdominal/*standards ; Republic of Korea ; Retrospective Studies ; Tomography, X-Ray Computed/*standards

This paper introduces the significance, the present development situation and some suggestions of the medical measurements.
Diagnostic Equipment ; standards ; Equipment and Supplies ; standards ; Magnetic Resonance Imaging ; instrumentation ; standards ; Medical Staff ; education ; Research Design ; standards ; Tomography, X-Ray Computed ; standards

OBJECTIVE: The CT accreditation program was established in 2004 by the Korean Institute for Accreditation of Medical Image (KIAMI) to confirm that there was proper quality assurance of computed tomography (CT) images. We reviewed all the failed CT phantom image evaluations performed in 2005 and 2006. MATERIALS AND METHODS: We analyzed 604 failed CT phantom image evaluations according to the type of evaluation, the size of the medical institution, the parameters of the phantom image testing and the manufacturing date of the CT scanners. RESULTS: The failure rates were 10.5% and 21.6% in 2005 and 2006, respectively. Spatial resolution was the most frequently failed parameter for the CT phantom image evaluations in both years (50.5% and 49%, respectively). The proportion of cases with artifacts increased in 2006 (from 4.5% to 37.8%). The failed cases in terms of image uniformity and the CT number of water decreased in 2006. The failure rate in general hospitals was lower than at other sites. In 2006, the proportion of CT scanners manufactured before 1995 decreased (from 12.9% to 9.3%). CONCLUSION: The continued progress in the CT accreditation program may achieve improved image quality and thereby improve the national health of Korea.
*Accreditation ; Korea ; Phantoms, Imaging ; Societies, Medical ; Tomography, X-Ray Computed/*standards

OBJECTIVE: To devise a new method to measure the amount of soft tissue in pulmonary ground-glass opacity nodules, and to compare the use of this method with a previous volumetric measurement method by use of a phantom study. MATERIALS AND METHODS: Phantom nodules were prepared with material from fixed normal swine lung. Forty nodules, each with a diameter of 10 mm, were made with a variable mean attenuation. The reference-standard amount of soft tissue in the nodules was obtained by dividing the weight by the specific gravity. The imaging data on the phantom nodules were acquired with the use of a 16-channel multidetector CT scanner. The CT-measured amount of soft tissue of the nodules was calculated as follows: soft tissue amount = volume x (1 + mean attenuation value / 1,000). The relative percentage error (RPE) between the CT-measured amount of the soft tissue and the reference-standard amount of the soft tissue was also measured. The RPEs determined with use of the new method were compared with the RPEs determined with the current volumetric measurement method by the use of the paired t test. RESULTS: The CT-measured amount of soft tissue showed a strong correlation with the reference-standard amount of soft tissue (R(2) = 0.996, p < 0.01). The mean RPE of the CT-measured amount of soft tissue in the nodules was -7.79 +/- 1.88%. The mean RPE of the CT-measured volume was 114.78 +/- 51.02%, which was significantly greater than the RPE of the CT-measured amount of soft tissue (p < 0.01). CONCLUSION: The amount of soft tissue measured by the use of CT reflects the reference-standard amount of soft tissue in the ground-glass opacity nodules much more accurately than does the use of the CT-measured volume.
Animals ; Lung Neoplasms/*radiography ; Phantoms, Imaging ; Reference Standards ; Swine ; *Tomography, X-Ray Computed

OBJECTIVE: To explore the high-risk fault risk of CT simulator and the main causes of the risk, and to put forward effective risk management strategies. METHODS: The failure mode and effect analysis method was used to identify and control the operational fault risk of CT simulator. RESULTS: 5 major fault components, 8 fault failure models and 17 failure causes were analyzed. The top 5 failure causes are:anode target surface burn caused by direct scanning without warming up the tube (590.4), tube failure (518.2), burnout of joints caused by aging of high voltage cables (424.2), motor carbon brush wear (304.8) and belt break (296.4). CONCLUSIONS The failure mode and effect analysis method can effectively identify the risk of equipment failure, and thus specifically formulate risk management and control measures to ensure the normal operation of equipment and the safety of doctors and patients.
Equipment Failure ; statistics & numerical data ; Humans ; Risk Management ; methods ; Tomography, X-Ray Computed ; standards

Computed tomography (CT) is an essential imaging modality. To solve the problem caused by increasing radiation exposure from CT scanner and to elevate the image quality, we aimed to apply the general objective image quality methods in CT image quality evaluation. After analyzing the perceptual features of CT image, we tested several popular objective image quality metrics, which focus on the similar perceptual features, on the CT image of phantom and animals. Experiments for verifying the feasibility were carried out. Compared with the subjective ratings from two professional radiation physicians, the complex wavelet-based structural similarity metric presents the better prediction results of the image quality.
Computer Simulation ; Equipment Design ; Humans ; Image Processing, Computer-Assisted ; instrumentation ; Quality Control ; Radiation Dosage ; Radiometry ; Tomography, X-Ray Computed ; standards

OBJECTIVES: To explore the characteristics of nasal bone fracture caused by blunt instrument, including the fracture types, the fracture repair, and the difference of manifestations between X-ray and CT. To provide reference for the identification. METHODS: The information of basic situation, fracture site, injury manner, diagnosis method, expert opinion of 95 adult nasal fracture cases caused by blunt object, which occurred in Gutian county of Fujian province from January 1999 to December 2013, were analyzed by descriptive statistics. The identification conclusions of different injuries were compared according to new and old standards as well. RESULTS: There were total 95 adults including 87 male and 8 female. The fracture site and quantity have significant correlation with the nasal bone anatomical relations and the direction and size of the force. Compound fracture was most common. The fracture that could not be determined by X-ray could be clearly diagnosed by CT examination. According to new and old standards, different fracture types have different identification conclusions. CONCLUSIONS There are gender differences in nasal bone fracture cases. Larger external force is easy to cause compound fracture. CT examination is significantly better than X-ray examination.
Adult ; Female ; Humans ; Male ; Nasal Bone/injuries* ; Radiography ; Reference Standards ; Sex Factors ; Skull Fractures/diagnostic imaging* ; Tomography, X-Ray Computed

This review article comprehensively discusses multidetector CT urography protocols and their role in imaging of the urinary tract in patients with hematuria.
Hematuria/etiology/*radiography ; Human ; Incidental Findings ; Sensitivity and Specificity ; Tomography, X-Ray Computed/*methods/standards ; Urinary Tract/abnormalities ; Urography/methods/standards ; Urologic Diseases/complications/congenital/radiography

Concerns have been raised over x-ray radiation dose associated with repeated computed tomography (CT) scans for tumor surveillance and radiotherapy planning. In this paper, we present a low-dose CT image reconstruction method for improving low-dose CT image quality. The method proposed exploited rich redundancy information from previous normal-dose scan image for optimizing the non-local weights construction in the original non-local means (NLM)-based low-dose image reconstruction. The objective 3D low-dose volume and the previous 3D normal-dose volume were first registered to reduce the anatomic structural dissimilarity between the two datasets, and the optimized non-local weights were constructed based on the registered normal-dose volume. To increase the efficiency of this method, GPU was utilized to accelerate the implementation. The experimental results showed that this method obviously improved the image quality, as compared with the original NLM method, by suppressing the noise-induced artifacts and preserving the edge information.
Algorithms ; Artifacts ; Humans ; Imaging, Three-Dimensional ; methods ; Phantoms, Imaging ; Radiation Dosage ; Radiation Protection ; standards ; Radiographic Image Interpretation, Computer-Assisted ; methods ; standards ; Tomography, X-Ray Computed ; methods