Radiography Technology Research Articles

A lattice scenario for a proton radiography accelerator

A proton radiography system is an accelerator-based facility. Especially high-energy proton radiography is an advanced hydrodynamics diagnostic tool, and it is the trend of radiography technology development. In this paper, a 20 GeV accelerator complex scenario, including a 35 MeV linac, a 1 GeV booster and a 20 GeV main ring, is introduced. The overall physics design of the proton radiography accelerator is described, including the design of each part of the accelerator and the choice of the main parameters.

Mammographic findings of women recalled for diagnostic work-up in digital versus screen-film mammography in a population-based screening program

Limited information is available concerning differences in the radiological findings of women recalled for diagnostic work-up in digital mammography (DM) versus screen-film mammography (SFM) screening. To compare the radiological findings, their positive predictive values (PPVs) for cancer and other process indicators of DM screening performed by computed radiography (CR) technology and SFM screening in a population-based program. The material consisted of women, 50-59 years of age, who were invited for screening: 30 153 women with DM in 2007-2008 and 32 939 women with SFM in 1999-2000. The attendance rate was 77.7% (23 440) in the DM arm and 83.8% (27 593) in the SFM arm. In the DM arm, 1.71% of those screened (401) and in the SFM arm 1.59% (438) were recalled for further work-up. The images resulting in the recall were classified as: 1) tumor-like mass, 2) parenchymal distortion/asymmetry, 3) calcifications, and 4) combination of mass and calcifications. The distributions of the various radiological findings and their PPVs for cancer were compared in both study groups. The recall rates, cancer detection rates, test specificities, and PPVs of the DM and SFM groups were also compared. Women were recalled for diagnostic work-up most often due to tumor-like mass. It was more common in SFM (1.08% per woman screened) than in DM (0.93%). The second most common finding was parenchymal distortion and asymmetry, more often in DM (0.58%) than in SFM (0.37%). Calcifications were the third most common finding. DM exposed calcifications more often (0.49%) than SFM (0.26%). The PPVs for cancer of the recalls were higher in DM than in SFM in all subgroups of radiological findings. The test specificities were similar (DM 98.9%, SFM 98.8%). Significantly more cancers were detected by DM (cancer detection rate 0.623% per woman screened, n=146) than by SFM (cancer detection rate 0.406% per woman screened, n=112). The PPVs for cancer of all recalls for diagnostic work-up were significantly higher in DM (36%) than in SFM (26%). In DM women were recalled for diagnostic work-up more often for calcifications, parenchymal distortions, and asymmetries than in SFM. In the case of tumor-like masses, more women were recalled in SFM. DM detected more cancers than SFM, and the PPVs for cancer were higher in DM than in SFM in all subgroups of radiological findings.

Muon radiography technology for detecting high-Z materials

This paper studies the possibility of using the scattering of cosmic muons to identify threatening high-Z materials. Various scenarios of threat material detection are simulated with the Geant4 toolkit. PoCA (Point of Closest Approach) algorithm reconstructing muon track gives 3D radiography images of the target material. Z-discrimination capability, effects of the placement of high-Z materials, shielding materials inside the cargo, and spatial resolution of position sensitive detector for muon radiography are carefully studied. Our results show that a detector position resolution of 50 μm is good enough for shielded materials detection.

디지털 방사선투과영상의 정밀성 평가에 관한 연구

Abstract Film based radiography imaging technique has been applied to the non-destructive test in medical, aircraft, and power industries contributing to the development of the industries. However, the complex process for imaging and analysis has increasingly demanded the reformation of the radiography test. A digital radiography imaging technologies has been com out from the demand. This study was mainly focused on the assessment on the accuracy for the each image from digital radiography test and film radiography test was proven to crate a better image in sensitivity than film radiography test. In the IQI (Image quality indicator) transmission test, one or two more line can be seen in digital image than in film image. When applying to the boiler tube weld, film image is detectable to the 1.0mm depth flaw; and digital image to the 0.5mm depth flaw. As a result of this study, digital radiography technology is determined to enhance the image quality, compared to film radiography technologiesKey Words : Non-destructive test, Digital radiography, Welding inspection

Needle vs. Powder Imaging Plate for Computer Radiography: Image Quality Measurement and Model Calculation

Computed radiography (CR) is a digital radiography technology in which a storage phosphor plate is used to store a latent X-ray image. The plate is exposed in a light-tight cassette and then read out in a scanner to create the digital image. Conventionally, CR powder imaging plates (PIP) are used based on BaFBr1-xIx:Eu2+ phosphor. The active layer consists of phosphor microcrystals in a polymer binder. A needle imaging plate (NIP), created by of vapor deposition of needle-shaped phosphor crystals, leads to better image quality because thicker phosphor layers, having higher X-ray absorption can be used. BaFBr1-xIx:Eu2+ is an excellent storage phosphor. It decomposes upon vaporization, however. For that reason, it is impossible to vapor deposit BaFBr1-xIx:Eu2+ needle crystals. At Agfa an excellent new storage phosphor, CsBr:Eu2+, was discovered. Since CsBr melts congruently, it allows thermal vapor deposition and production of NIP's. Measurements demonstrate that CsBr:Eu2+ NIP's allow to double CR image quality (DQE). A linear-systems approach is used to model signal and noise transfer in a CR system using PIP or NIP. The transfers are described by cascading transfer relationships for each process. The calculated image quality (DQE) is in good agreement with measurement for the PIP system. The model overestimates the NIP system DQE at high spatial frequencies. An overestimation of the system gain may be the reason.

The Strategy to be "Paperless" Via a Cost-Effective Filmless Plan

The group of folks assigned to the project were identified, and on April 23, 2001, an Request For Information (RFI) was released to 11 preidentified Picture Archiving Communication System (PACS) vendors. Our project was unique in 2 respects. First, there was an aggressive timeline. Second there was specific outpatient environment requirements. There was a need to move images and other patient-related data between several sites while depending heavily on the Wide Area Network (WAN) design rather than the typical Local Area Network (LAN) configuration. We learned quickly that there was not one live site, at which we could visit to observe our vision in action, nor had any solution been built to accomplish our specific objectives. The months of May, June, and July consisted of vendor meetings, RFI response reviews and, clinical and corporate visits ending on August 9, 2001 when our prime vendor of choice was selected. During this process, we identified deal breakers outlining specific needs for "go live," which is targeted for Q2 (2nd Quarter) 2002. The biggest workflow opportunity is to be paperless as well as filmless. By this we not only mean traditional RIS information but also patient documents (insurance information, physician script) as well as modality-patient-specific information. All of this information needs to be available electronically to accomplish) any patient record, any place, any time! The month of August was filled with WAN and LAN solution investigations. The solution of choice will be both cost effective and challenged to achieve 99.9% reliability. A cost-benefit analysis was performed and reviewed to better understand our return on investment. The months of September and October have been dedicated to Computerized Radiography (CR) technology. The TEAM reviewed 3 solutions, which consisted of both sit-down sessions as well as clinical site assessments. Again, "deal breaker" criteria were summarized and a solution chosen. Contract negotiations will soon conclude, and an aggressive implementation will begin!

Comparison of an amorphous silicon/cesium iodide flat-panel digital chest radiography system with screen/film and computed radiography systems--a contrast-detail phantom study.

Flat-panel (FP) based digital radiography systems have recently been introduced as a new and improved digital radiography technology; it is important to evaluate and compare this new technology with currently widely used conventional screen/film (SF) and computed radiography (CR) techniques. In this study, the low-contrast performance of an amorphous silicon/cesium iodide (aSi/Csl)-based flat-panel digital chest radiography system is compared to those of a screen/film and a computed radiography system by measuring their contrast-detail curves. Also studied were the effects of image enhancement in printing the digital images and dependence on kVp and incident exposure. It was found that the FP system demonstrated significantly better low-contrast performance than the SF or CR systems. It was estimated that a dose savings of 70%-90% could be achieved to match the low-contrast performance of the FP images to that of the SF images. This dose saving was also found to increase with the object size. No significant difference was observed in low-contrast performances between the SF and CR systems. The use of clinical enhancement protocols for printing digital images was found to be essential and result in better low-contrast performance. No significant effects were observed for different kVps. From the results of this contrast-detail phantom study, the aSi/CsI-based flat-panel digital chest system should perform better under clinical situations for detection of low-contrast objects such as lung nodules. However, proper processing prior to printing would be essential to realizing this better performance.

Digital mammography performed with computed radiography technology

Introduced by Fuji Photo Film Japan in the early 1980s, computed radiography (CR) technology has developed considerably since then to become the mature widely installed technology it is today (about 7500 systems worldwide). Various mammographic examinations require high performance results to which CR complies on demand or following some procedures such as geometrical magnification carried out during the examination. The basic CR principles and digital image processing as well as technical improvements are detailed in this study, which also includes a synthesis of the articles on CR mammographic applications referenced in the bibliography, focusing on strong points, limits and current methods of surpassing these limits. New CR technology development perspectives in mammography and computed assisted diagnosis (CAD) algorithms will allow wider use of this method in the near future.

Digital radiography and conventional imaging of the chest: a comparison of observer performance.

The purpose of this study was to compare observer performance in interpreting high-quality, digitally acquired computed radiographs of the chest displayed on either laser-printed radiographs or a workstation with observer performance in interpreting conventional chest radiographs. We performed a receiver-operating-characteristic study in which the presence or absence of five abnormalities was determined by nine experienced radiologists on 310 posteroanterior radiographs of the chest displayed in three forms: conventional radiographs, laser-printed films of digital radiographs, and digital radiographs on a high-resolution workstation. The results of our study suggest that observer performance with laser-printed films of digital radiographs obtained with high-resolution (4K x 5K), high-contrast sensitivity (12 bits) and appropriate exposure is comparable to observer performance with conventional radiographs. Observer performance with digital radiographs displayed on the workstation was found to be significantly lower for abnormalities that contained high-frequency and low-contrast information (e.g., interstitial disease and pneumothorax). Computed radiography technology can produce image quality that is adequate for interpreting posteroanterior radiographs of the chest. Observer performance is not as good when radiographs displayed on workstations are used to diagnose specific abnormalities.

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Training of Radiologic Technologists

On Sept. 7, 1966, 350 people gathered at the University of Maryland Center of Adult Education as guests of the Division of Radiological Health of the United States Public Health Service to consider problems relating to the training of radiologic technologists (1). As stated by Dr. Donald R. Chadwick, Chief of the Division, the basic question the Conference considered was “What will it take to provide adequate numbers of qualified operators of x-ray machines in medicine?” Never before have so many persons, knowledgeable and experienced in the various facets of radiologic technology, been gathered under one roof: 22 radiologists including half the members of the Commission on Technologist Affairs of the American College of Radiology; 80 radiologic technologists (almost all of them teachers and supervisors and including the national officers of the American Society of Radiologic Technologists); officers of the American Registry of Radiologic Technologists, American Radiography Technology, and of the New York State Licensing Board; 10 physicists; representatives of labor and in-dustry, and a host of federal, state, and municipal public health officials. The Center of Adult Education is a large, new, comfortable hotel-like facility, rather remotely situated on a corner of the University of Maryland campus. It provided an ideal milieu for a conference of this sort, where the participants could devote their entire time to the work in hand, as they did, without the distractions which would have been present if the conference had been held in a large city hotel. The session opened on Wednesday evening with dinner and a “get-acquainted” social hour, extended throughout the day and evening on Thursday, and closed on Friday afternoon. Thursday forenoon was devoted to formal presentations designed to seek out and present the basic questions to be considered. Group discussions followed on Thursday afternoon and Friday forenoon. At the closing general sessions on Friday the moderators of the four groups summarized the conclusions of the groups and a general discussion period followed. Finally, summary talks were given by Walter D. Jacobs, Ph.D., Associate Professor of Government and Politics, University of Maryland, who had been brought in as an outside observer; Clark Warren, R. T., Past President of the ASRT; and Harold O. Peterson, M.D., Chairman of the ACR Committee on Technologist Affairs. The keynote address on Thursday was presented by Dr. Russell H. Morgan, Professor of Radiological Science, Johns Hopkins University. Doctor Morgan, who has been Chairman of the National Advisory Committee on Radiation (NACOR) since its inception in 1957, summarized some of the recent findings of the Committee (2) and posed a number of questions.