Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Software Validation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed2001

Extraction of full absorption peaks in airborne gamma-spectrometry by filtering techniques coupled with a study of the derivatives. Comparison with the window method.

In this paper, an adaptation of a spectral profile analysis method, currently used in high-resolution spectrometry, to airborne gamma measurements is presented. A new algorithm has been developed for extraction of full absorption peaks by studying the variations in the spectral profile of data recorded with large-volume NaI detectors (16 l) with a short sampling time (2 s). The use of digital filters, taking into consideration the characteristics of the absorption peaks, significantly reduced the counting fluctuations, making detection possible based on study of the first and second derivatives. The absorption peaks are then obtained by modelling, followed by subtraction of the Compton continuum in the detection window. Compared to the conventional stripping ratio method, spectral profile analysis offers similar performance for the natural radioelements. The 137Cs 1SD detection limit is approximately 1200 Bq/m2 in a natural background of 200 Bq/kg 40K, 33 Bq/kg 238U and 33 Bq/kg 232Th. At low energy the very high continuum leads to detection limits similar to those obtained by the windows method, but the results obtained are more reliable. In the presence of peak overlaps, however, analysis of the spectral profile alone is not sufficient to separate the peaks, and further processing is necessary. Within the framework of environmental monitoring studies, spectral profile analysis is of great interest because it does not require any assumptions about the nature of the nuclides. The calculation of the concentrations from the results obtained is simple and reliable, since only the full absorption contributions are taken into consideration. A quantitative estimate of radioactive anomalies can thus be obtained rapidly.

Air Pollution, Radioactive↗
PubMed2004

The accuracy of preoperative orthognathic predictions.

We assessed the accuracy of preoperative OPAL trade mark orthognathic predictions by retrospective analysis of 25 Class II patients who had had orthodontic treatment combined with mandibular advancement osteotomy. Preoperative and postoperative lateral cephalographs were digitised and surgical predictions generated using OPAL software. Each prediction was compared with the corresponding clinical changes. We also made a method error study by doing a random retracing of 25 cephalographs. Predictions of some of the principal OPAL values (SNA, ANB, LAFH%, OJ, OB) were reasonably accurate in terms of mean values. However, there were large individual variations for most variables and predictions of the vertical skeletal, incisor, and Wits measurements were imprecise. In particular, there was a bias towards under-prediction of the vertical skeletal changes when there was more backward mandibular rotation than anticipated. Immediate postoperative cephalographs were also affected by a 2.1mm mean downward displacement of the mandible as a result of the surgical wafer.

Adult↗
PubMed2003

Flexible ligand docking using evolutionary algorithms: investigating the effects of variation operators and local search hybrids.

The docking of ligands to proteins can be formulated as a computational problem where the task is to find the most favorable energetic conformation among the large space of possible protein-ligand complexes. Stochastic search methods such as evolutionary algorithms (EAs) can be used to sample large search spaces effectively and is one of the commonly used methods for flexible ligand docking. During the last decade, several EAs using different variation operators have been introduced, such as the ones provided with the AutoDock program. In this paper we evaluate the performance of different EA settings such as choice of variation operators, population size, and usage of local search. The comparison is performed on a suite of six docking problems previously used to evaluate the performance of search algorithms provided with the AutoDock program package. The results from our investigation confirm that the choice of variation operators has an impact on the search-capabilities of EAs. The introduced DockEA using the best settings found obtained the overall best docking solutions compared to the Lamarckian GA (LGA) provided with AutoDock. Furthermore, the DockEA proved to be more robust than the LGA (in terms of reproducing the results in several runs) on the more difficult problems with a high number of flexible torsion angles.

Algorithms↗
PubMed2002

Validation of Vitek version 7.01 software for testing staphylococci against vancomycin.

We tested 143 isolates of staphylococci with vancomycin by the National Committee for Clinical Laboratory Standards broth microdilution (BMD) reference method and compared the results to those generated using the Vitek automated system (GPS-105 and GPS-107 cards and version 7.01 software). For ten isolates, the vancomycin MICs by BMD were 8 microg/ml. By Vitek, the vancomycin MICs ranged from 2 to 16 microg/ml. Vancomycin MICs of > or =32 microg/ml were reported for two additional isolates by Vitek; however, the MICs decreased to < or =0.5 microg/ml on retesting. By BMD, the vancomycin MICs for both isolates were 1 microg/ml. While the modal vancomycin MIC results by BMD for S. aureus and coagulase-negative staphylococci (CoNS) were both 1 microg/ml, Vitek results showed a mode of < or =0.5 microg/ml for S. aureus, and a mode of 2 microg/ml for CoNS. Vitek did not report vancomycin MICs of 1 or 4 microg/ml for any of the isolates tested. While the sensitivity of detecting staphylococci with reduced susceptibility to vancomycin appears to be improved with Vitek version 7.01 software, when compared to earlier software versions, laboratories may notice an overall shift in MIC data toward higher vancomycin MICs, although for the most part, this does not affect the categorical interpretations of the results.

Anti-Bacterial Agents↗
PubMed1999

Computer-assisted instructions for patients with bronchial asthma.

We produced computer-assisted instruction (CAI) software for bronchial asthma patients (asthma educational system with computer-assisted instruction; ASTCAI) to assist in self-management and avoid asthmatic attacks and death. ASTCAI is a question-and-answer program operating in a multimedia environment, and was evaluated from questionnaires which 33 patients were asked. Thirty-two patients could perform ASTCAI without any assistance. The responses of 31 patients (94%) indicated that they had no difficulty with manipulation, and 29 patients (88%) stated that the program was beneficial to control of their asthma. Elderly patients (over 65) required more time than younger adults. Emergency visits or admissions of at least 1 year after the first CAI trial decreased in eight out of 26 patients, while only two patients deteriorated compared to the previous year. Our results show that CAI is feasible for most patients, and through active self-learning CAI can improve motivation for self-management as well as supplement the physician's instructions.

Adolescent↗
PubMed1994

[Continuous administration of drugs by infusion pumps. Presentation of an infusion rate mathematical computing software].

Intensive therapy includes continuous delivery of drugs with infusion pump. This article describes an infusion rate computing programme using a Macintosh micro-computer and the HyperCard 2 software. The latter permits the classification of data onto cards collected in stacks. The card that is displayed when the programme is launched shows fifteen buttons assigned to various drugs. Click upon a button opens the corresponding card which displays the presentation of the drug and suggests a dilution. The next step associates input of patient's weight into the appropriate field and a click on the main button. A display then indicates for various standard dosages, the corresponding rate of infusion in mL.h-1 and the daily consumption of the drug. In order to avoid casual or voluntary changes of the setting, soft securities have been inserted in the programme.

Humans↗
PubMed2001

Bi-directional computing architecture for time series prediction.

A number of neural network models and training procedures for time series prediction have been proposed in the technical literature. These models studied for different time-variant data sets have typically used uni-directional computation flow or its modifications. In this study, on the contrary, the concept of bi-directional computational style is proposed and applied to prediction tasks. A bi-directional neural network model consists of two subnetworks performing two types of signal transformations bi-directionally. The networks also receive complementary signals from each other through mutual connections. The model not only deals with the conventional future prediction task, but also with the past prediction, an additional task from the viewpoint of the conventional approach. An improvement of the performance is achieved through making use of the future-past information integration. Since the coupling effects help the proposed model improve its performance, it is found that the prediction score is better than with the traditional uni-directional method. The bi-directional predicting architecture has been found to perform better than the conventional one when tested with standard benchmark sunspots data.

Data Interpretation, Statistical↗
PubMedDate not supplied

Automated three-dimensional quantification of myocardial perfusion and brain SPECT.

To allow automated and objective reading of nuclear medicine tomography, we have developed a set of tools for clinical analysis of myocardial perfusion tomography (PERFIT) and Brain SPECT/PET (BRASS). We exploit algorithms for image registration and use three-dimensional (3D) "normal models" for individual patient comparisons to composite datasets on a "voxel-by-voxel basis" in order to automatically determine the statistically significant abnormalities. A multistage, 3D iterative inter-subject registration of patient images to normal templates is applied, including automated masking of the external activity before final fit. In separate projects, the software has been applied to the analysis of myocardial perfusion SPECT, as well as brain SPECT and PET data. Automatic reading was consistent with visual analysis; it can be applied to the whole spectrum of clinical images, and aid physicians in the daily interpretation of tomographic nuclear medicine images.

Algorithms↗
PubMedDate not supplied

Workflow in nuclear medicine.

This paper discusses a workflow management system for nuclear medicine. It augments the more conventional PACS with automatic transfer of studies along the chain of activities making up an examination in nuclear medicine. A prototype system has been designed, built, and installed in a department of nuclear medicine, active in a network of hospitals.

Belgium↗
PubMedDate not supplied

European Medical Device Directive: impact on nuclear medicine.

The European Council Directive 93/42/EEC concerning medical devices (14 June 1993) assigns new responsibilities and imposes technical requirements both to the manufacturer and user of medical devices. In this paper the general outlines of the directive are discussed with a particular emphasis on the risk classification of products, the compliance and evaluation process and the CE-marking regulations. Furthermore, some practical implications are highlighted for devices and tools relevant to the field of nuclear medicine such as radiation detectors, gamma- and PET-cameras and software.

Absorptiometry, Photon↗
PubMedDate not supplied

Testing the precision of stereotactic planning systems.

The implementation of effective methods of testing the precision of computations, is essential for the development of medical systems, such as the stereotactic planning software for neurosurgery. During the development of our planning system we designed, in addition to the traditional phantom test, some tests based on digitally constructed images. These tests give quantitative and qualitative measurement of the precision and stability of the calculations, and are easy to implement and isolate the program error from the mechanical and image acquisition errors. The verification of our software shows good precision in coordinates calculation and a significant impact of pixel size and interscan spacing on the precision.

Brain↗
PubMed2002

Verification of temporal scheduling constraints in clinical practice guidelines.

The computerization of clinical practice guidelines is a significant scientific challenge for the medical informatics community. One frequently reported factor hindering this objective is the existence of deficiencies within guideline knowledge. In this paper, we focus on the detection of flaws within temporal scheduling constraints. Temporal scheduling constraints are important elements of therapy management, and are frequently incorporated in clinical practice guidelines. We present a suitable verification method that is based on calculating the minimal network of temporal constraints on the execution of guideline activities. Our method serves three purposes: (1) it checks whether temporal scheduling constraints are consistent with scheduling constraints implied by control flow operators and the hierarchical structuring of a guideline; (2) it yields suggestions for an equivalent, yet more explicit representation of non-minimal constraints; (3) it can be used by the guideline interpreter to assemble feasible time intervals for the execution of each guideline activity. We evaluate our approach by applying it to a guideline specified in the Asbru language. For this purpose, we implemented a prototype verifier. Although we concentrate on the guideline representation language Asbru as the demonstration medium of our method within this paper, our approach can be reused to verify several alternative guideline representation formats.

Humans↗
PubMed2003

The reliability of "Analyze" software in measuring orbital volume utilizing CT-derived data.

INTRODUCTION: Craniomaxillofacial surgeons require to estimate the orbital volume in a variety of clinical situations. This paper evaluates a new method based on software analysis of computerized tomography (CT) scan data. MATERIAL AND METHODS: Five dried skulls with prosthetic globes and periorbita were non-helically scanned in an Elscint 2400 CT scanner. Images obtained were processed using the "Analyze" software package and results compared to the volume of the intraorbital prosthesis as determined by a volume displacement gravimetric method. RESULTS: Estimates of volume produced by the software varied from the gold standard by 0.06-50.44%, with a mean error of 8.8%. CONCLUSION: Despite the use of a variety of scan protocols it was not possible to obtain results with "Analyze" software which were sufficiently accurate for clinical use.

Eye, Artificial↗
PubMed2003

An Internet-based evaluation system for a surgical residency program.

BACKGROUND: Efficient and meaningful evaluation of performance is critical to the professional development of trainees in surgical residency programs. Current paper-based evaluation instruments have numerous limitations. We developed an Internet-based evaluation system to more rapidly and efficiently assess the experience of residents, faculty, and rotations. STUDY DESIGN: An on-line evaluation system was designed and implemented in October 1999. Custom evaluations were created for residents, faculty, and rotations. Evaluations were completed via the Internet site from remote locations with standard computers and standard Web browser software. Completed evaluations were automatically available on-line for review and data analysis. Data were analyzed by chi-square analysis with a probability value of less than 0.05 considered statistically significant. RESULTS: Compliance in completion of evaluations improved from 50% to 80% in the initial 6 months of implementation (p < 0.01) with the Web-based system. There was no significant difference between faculty and resident compliance. In evaluation of "ease of use," a total of 612 responses were received over this period with a total average score of 3.5 (5 point scale, 5 = strongly agree). Residents' opinions (average score, 3.69) were slightly more positive than those of faculty (average score, 3.31). Confidentiality was improved over paper-based systems by a detailed security network. CONCLUSIONS: This Internet-based evaluation system is a potentially powerful instrument for evaluating our surgical residency program and making changes to improve the educational experience in a timely and efficient manner.

Attitude of Health Personnel↗
PubMed2000

MR volumetric analysis of the human basal ganglia: normative data.

RATIONALE AND OBJECTIVES: The authors undertook this study to identify a precise, semiautomated, reproducible magnetic resonance (MR) imaging technique for measuring the basal ganglia, to establish normative volumetric data, and to verify the presence of previously reported asymmetries. MATERIALS AND METHODS: Twenty-eight healthy adults underwent cranial MR examination. The volumes of the various components of the basal ganglia were measured by means of a combination of thresholding and manual tracing techniques performed with specialized software. The validity of these measurements was assessed by fashioning, imaging, and measuring a practical basal ganglia phantom. Measurement accuracy was also established by means of inter- and intrarater reliability indexes. Normalized volumes were statistically analyzed with analysis of variance and paired t tests. RESULTS: The absolute values of the various components of the basal ganglia varied widely even though the volumes were normalized to differences in intracranial volume. The right caudate nucleus volume was significantly (P < .000001) larger than the left in both men and women and in both right-handed and non-right-handed subjects. This asymmetry led to an increase in the overall volume of the basal ganglia on the right. CONCLUSION: The authors have defined a precise, reproducible technique for measuring various components of the basal ganglia and have established normative data. The basal ganglia, similar to other brain structures, exhibit hemispheric lateralization.

Adult↗