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At least 973 records · Page 54Linked to original sources

Multicellular dosimetry in voxel geometry for targeted radionuclide therapy.

A software package to investigate absorbed doses and dose-rates at the cellular and multicellular scale has been developed that considers two- and three-dimensional activity distributions and makes use of analytical representations of the point-dose kernels for (131)I, (32)P, and (90)Y. This software allows cell assemblies to be simulated by definition of the number, size, and geometry of cells and their nuclei, and radionuclide uptake can be specified to occur within the nucleus, the cytoplasm, at the membrane, or within the extracellular space. The software has been validated at a cellular scale by comparison with results obtained using spherical geometry, as found in the literature. At a multicellular scale, comparisons were made with a Monte Carlo simulation in voxel geometry. The software has been designed to work within a user-defined voxel geometry. This geometry is useful not only to simulate complex cell assemblies and realistic heterogeneous radionuclide distributions, but will also allow the use of histological and autoradiographic data. Absorbed dose distributions for a single cell calculated using this code varied significantly with activity localization within the cell, and to a lesser extent, with the cellular geometry. At a multicellular level, a two-dimensional heterogeneous activity distribution inferred from a two-dimensional image of a slice throughout a spheroid was used to calculate a dose-rate distribution. This resulted in a heterogeneous dose-rate delivery even for longer-range radionuclides such as (90)Y and (32)P.

Absorption↗

[Assesing the GRDOSIS Software program as a tool to analyse drug usase by DRGs].

OBJECTIVE: To validate the GRDOSIS software program as a tool to calculate Spanish drug weights within diagnosis-related groups (DRGs), and to analyse information used in this calculation. MATERIAL AND METHODS: Information corresponding to a 7-hospital sample is analysed after exchanging data between the minimum basic data set processed by the DRG-grouping program Estación Clínica -3M and unit-dose drug consumption. Data are purged by eliminating cases with an unusual (either long or short) length of stay in each DRG, and both weights and pondered weights are calculated. Data from the 5 most prevalent DRGs are analysed by using the different options provided by the software program, with the aim of detecting intervention points in order to improve results. RESULTS: Extreme case elimination noticeably reduces mean cost per DRG. A reduced group of DRGs represents a high percentage of total cost. Similarly, a reduced number of drugs may represent a high percentage of cost within a given DRG. The use of specific therapeutic groups for specific DRGs is demonstrated, as is the correct use of first-choice drugs versus other therapeutic options within therapeutic groups. An unwarranted variability regarding drug administration dosing and frequency is, however, observed. CONCLUSIONS: The GRDOSIS software program proves itself a powerful tool for both the qualitative (drug usage profiles, dosage) and quantitative (costs) analysis of information originating in a Pharmacy Department

Diagnosis-Related Groups↗

Quality auditing of chromatographic data.

We have developed a method for consistent, in-depth audit of the integrity of chromatographic records. The approach includes definition of the analyte, the method of analyte sample preparation and analysis, and the analyte concentration range. Acceptance criteria (if any) defined in the protocol or method are compared to the data. Run parameters are compared to those specified in the methodology. Certification of the standard is verified and the limit of quantitation for each run is identified and compared to data. Reasons for data discard and/or reassay are examined. If calculation software is not validated, representative calculations are recomputed and chromatograms are examined for attributability. These parameters are examined in addition to other Good Laboratory practice considerations such as sample identity, sample integrity, and transcription accuracy.

Chromatography↗

An object-oriented programming system for the integration of internet-based bioinformatics resources.

The Internet consists of a vast inhomogeneous reservoir of data. Developing software that can integrate a wide variety of different data sources is a major challenge that must be addressed for the realisation of the full potential of the Internet as a scientific research tool. This article presents a semi-automated object-oriented programming system for integrating web-based resources. We demonstrate that the current Internet standards (HTML, CGI [common gateway interface], Java, etc.) can be exploited to develop a data retrieval system that scans existing web interfaces and then uses a set of rules to generate new Java code that can automatically retrieve data from the Web. The validity of the software has been demonstrated by testing it on several biological databases. We also examine the current limitations of the Internet and discuss the need for the development of universal standards for web-based data.

Computational Biology↗

Conventional and indirect digital radiographic interpretation of oral unilocular radiolucent lesions.

OBJECTIVES: To compare the diagnostic processes for the main unilocular radiolucent lesions of the mandible in the presence of the following variables: conventional and digital radiography, specialization of the examiner and type of lesion. METHODS: Twenty-four panoramic radiographs were selected from the archives of the AC Camargo Hospital (São Paulo, Brazil), aiming at comparing the diagnostic processes for similar unilocular radiolucent lesions of the mandible, with the following histopathological diagnosis: six ameloblastomas, six dentigerous cysts, six keratocysts and six traumatic bone cysts. The radiographs were scanned and processed using the Trophy 2000 software. Three specialists, each from four related areas (pathologists, stomatologists, radiologists and oral surgeons), randomly evaluated the radiographs before and after digitalization. RESULTS: The kappa statistic showed a high level of agreement between results obtained using the two radiographic techniques. This means that, in general, the examiners diagnosed the same cases correctly or incorrectly regardless of the method used. CONCLUSIONS: Based on generalized estimating equations, it was concluded that the probability of correct diagnosis does not depend on the kind of lesion, on the radiographic technique or on the specialization of the examiner. In view of the differing opinions of the specialists regarding the diagnostic validity of some software features available and of the results obtained in indirect digital technique, it may be reasonable to reconsider its use for diagnosis of bone pathology.

Ameloblastoma↗

A new approach: reusable real-time database for medical instrumentation applications.

Medical instrumentation (MI) software development work differs from other software development works mainly in the testing and validation phase. For MI software, this phase has always been most difficult, time-consuming and yet the most doubted phase. The primary reason being the input to these programs (ie) the physiological signals like ECG, pulse, etc. To be more specific, the problem is because 1. These physiological signal patterns vary so widely from person to person and hence these programs have to be validated statistically on all categories of persons including those on the extreme ends. 2. There are also artifacts riding on these signals (inherent, intentional or due to inevitable physical movements) 3. These signals are real-time ones to the order of a second. Above all, 4. They are not reproducible patterns, if you need them for study and analysis at a later date. Though it is tough to find alternatives for the present technique of statistical validation, there can be ways to make use of this time-consuming validation process to its fullest potential. One such way is to make a kind of 'CAPTURE-RETAIN AND REUSE' databases that can reduce the future efforts in the validation phase substantially. The main areas where these databases can make vital contributions are: 1. Medical Instrumentation software testing and validation 2. Medical Instruments' results and performance comparison 3. Expert system building, testing and enhancement of its capabilities.

Evaluation Studies as Topic↗

Effectiveness of comparison overlays generated with DentalPrint software in bite mark analysis.

Validation studies of the new DentalPrint software were carried out with experimental bite marks in pigskin. The bite marks were digitally photographed according to the ABFO guidelines for evidence collection. Dental casts used in the experiment were scanned in 3D and 2D, and comparison overlays were generated using DentalPrint and Adobe Photoshop software, respectively. Digitized photographs of the experimental bite marks and the biting edges obtained in the overlays were compared by two different examiners to analyze the impact of training and experience with the two methods. Receiver operating characteristic (ROC) analysis, sensitivity, specificity, and 95% confidence intervals for each cutoff point were calculated. The expert examiner using DentalPrint obtained the best results, with an area under the ROC curve of 0.76 (SE=0.057; CI at 95%=0.652-0.876). Fairly high specificity values were found for DentalPrint, and the best results were obtained for the cutoff value that discriminated between the examiner's response "biter" and the rest of the possible (specificity 97.9%, CI at 95%=93.2%-99.6%). Therefore, the results presented here indicate that DentalPrint is a useful, accurate tool for forensic purposes, although further research on the comparison process is needed to enhance the validity of bite mark analysis.

Animals↗

Validation of a chromatography data analysis software.

The performance of chromatography data analysis software packages is of cardinal importance when the precision and the accuracy of a chromatographic system are evaluated. Users cannot rely on a procedure generating chromatographic data of known accuracy. Holistic approaches cannot always be entirely trusted. We propose a new method consisting in validating a data analysis package against computer generated chromatograms of exactly known characteristics by feeding these chromatograms into the vendor supplied software and comparing the results supplied by the software and the exact answers. We simulated symmetrical and tailing chromatograms and processed these signals with the Agilent Technologies (formerly Hewlett-Packard) ChemStation software. The noise profile (i.e. the power spectrum of the baseline) was determined for a HPLC UV detector prior to the calculations, and chromatograms of different signal-to-noise ratios were used for the analysis. For every chromatogram, we simulated 25 replicates with identical signal-to-noise ratios but different noise sequences. In this manner, both the random and the systematic errors of the retention data and peak shape characteristics can be evaluated. When analyzing tailing peaks, we simulated the effects of extra-column band broadening and those of column overload. Our calculations show that the general performance of the data analysis system studied is excellent. The contribution of the random error originating from the data analysis procedure is in most cases negligible compared to the repeatability of the chromatographic measurement itself.

Chromatography, High Pressure Liquid↗

Experimental validation of coincidence summing corrections computed by the ETNA software.

The ETNA software has been developed to compute efficiency transfer and coincidence summing corrections. Different experiments are combined to test the validity of this last facility. Point sources with multi-gamma emitters are measured at several source-to-detector distances. Experimental correction factors are determined from the variation in the peaks' relative intensities versus the geometrical conditions. The ETNA code is used to compute the corrections due to coincidence summing for the same geometries. The calculated values are compared to the experimental ones.

Algorithms↗

Precise area determination of skin-prick tests: validation of a scanning device and software for a personal computer.

When skin-prick tests (SPTs) are used quantitatively, the circumference of the weal and/or the flare is outlined using a felt tip pen, and transferred to paper by adhesive tape. The aim of the study was to develop and validate a procedure, objectively and precisely determining these areas after transfer to paper. A system was developed enabling the drawing of the area of weal or flare to be read by a hand-held scanner and calculated on a personal computer. Areas in the 5-500 mm2 range could be determined with day-to-day and interoperator coefficients of variation (CVs) of 3.1% and 1.8%, respectively. Accuracy was determined in two ways: by correlation to cutting/weighing of four times enlarged SPT areas (r2 = 0.999, P < 0.001) and by measuring standardized areas (deviations less than intra-assay CV, i.e. 1-2%). For comparison, CV of alternative methods were also determined: eight different areas (9-76 mm2) were evaluated in quadruplicate using the SPT-scanner (CV = 1.4%), by cutting/weighing of paper (CV = 2.3%), by digitizing (CV = 4.4%) or by measuring longest and orthogonal diameters (CV = 13.6%). In conclusion, the scanning device and software provides an objective and reproducible procedure for rapid determination of SPT areas. When areas are determined by scanning, digitizing or cutting/weighing the variations in area determination becomes negligible compared to the variations of the entire skin test procedure.

Diagnosis, Computer-Assisted↗

Remote electronic blood release system.

BACKGROUND: The Hunter Area Pathology Service provides transfusion services to 4 metropolitan and 11 rural hospitals in Australia. To improve blood availability, conserve blood stocks, and reduce crossmatch-to-transfusion ratios, a networked electronic blood release system (EBRS) has been developed for computer cross-matching within the laboratory and at sites remote from the transfusion laboratory. It is innovative, in that non-laboratory staffs have been trained to release computer-matched blood at remote hospitals without transfusion laboratories. STUDY DESIGN AND METHODS: The EBRS software was tested and validated according to the Australian software standards AS 3563.1 and 3563.2 (1991). Over 7000 units were released by the EBRS in a laboratory trial conducted in conjunction with the conventional immediate-spin crossmatch. A further, 12-month study was conducted within the laboratory before the staged implementation of the EBRS at the remote hospitals. RESULTS: The EBRS has resulted in 1) a 25-percent reduction in the number of units requested by the medical staff, resulting from the reduction in time needed to provide compatible blood due to the elimination of the serologic crossmatch; 2) better blood stock management (reducing outdated red cell units by 30%); and 3) significant savings in laboratory workload (savings of approximately 100 hours/month). In addition, the rapid availability of computer-crossmatched red cells in emergency situations has enhanced patient safety. CONCLUSION: The EBRS is a safe and efficient means of providing red cells within the laboratory and at remote hospitals without laboratory services.

Blood Banks↗

Good Automated Laboratory Practices and other standards: validation of computer systems in the PC environment.

In summary, the validation of purchased software and add-on programs requires careful examination of the situation to determine the most effective and logical methods. A standard validation methodology that is used for larger systems would be difficult and possibly dangerous to employ for a PC system because of the significant differences between the environments. It should be noted, however, that there are almost daily changes in the computer software industry. A number of potential solutions have emerged over the past few years that can be applied to reduce the concerns caused by the apparently insufficient controls in the PC environment. For example, currently available technologies would permit multiple PC users to access a secure central application or repository of data and prevent them from making changes to a validated system or database. A properly designed system could enable these distributed users to use the data to perform their required functions, while maintaining a validated state.

Clinical Laboratory Information Systems↗

Laboratory information system test environment: validate upgrades, prevent disasters, and assist training.

A laboratory information system (LIS) test environment allows the laboratory to run and test programs without affecting the current production environment. This is essential for successfully introducing system enhancements and upgrades because it allows the LIS manager to uncover software errors before introducing them into the actual LIS system. A test environment is also a useful tool for training employees. In addition, a test environment enables laboratories to validate software before use in the live environment, which will probably be required by the Food and Drug Administration and the Health Care Financing Administration inspectors now that LISs are considered medical devices. This article examines the benefits, uses, and limitations of an LIS test environment; discusses the computer resources required; and explores the process of installing and validating a software release.

Clinical Laboratory Information Systems↗

Can the same edge-detection algorithm be applied to on-line and off-line analysis systems? Validation of a new cinefilm-based geometric coronary measurement software.

In the Cardiovascular Measurement System (CMS) the edge-detection algorithm, which was primarily designed for the Philips digital cardiac imaging system (DCI), is applied to cinefilms. Comparative validation of CMS and DCI was performed in vitro and in vivo with intracoronary insertion of stenosis phantoms in anesthetized pigs. The "obstruction diameter" (OD) was measured at the artificial stenoses visualized by angiography with calibration at the isocenter (ISO) and catheter calibration (CATH) and compared with the true phantom diameters. A clinical comparison of OD, reference diameter (RD), and percentage diameter stenosis (DS) was performed on 70 corresponding images from post-PTCA angiograms. In vitro, OD (CMS) yielded an accuracy of 0.18 +/- 0.14 mm with 100% (correlation coefficient: r = 0.97, y = 0.06 + 0.75x, standard error of estimate [SEE] = 0.09) and 0.19 +/- 0.15 mm with 50% contrast (r = 0.94, y = 0.02 + 0.81 x). OD (DCI) yielded an accuracy of 0.11 +/- 0.06 mm with 100% (r = 0.99, y = -0.03 + 0.91 x, SEE = 0.05) and 0.24 +/- 0.13 mm with 50% contrast (r = 0.94, y = 0.29 + 6.69 x, SEE = 0.12). In vivo, OD (CMS) yielded an accuracy of 0.18 +/- 0.23 mm with ISO (r = 0.89, y = 0.02 + 0.83 x, SEE = 0.22) and 0.26 +/- 0.24 mm with CATH (r = 0.89, y = 0.06 + 0.72 x, SEE = 0.19). OD (DCI) yielded an accuracy of 0.08 +/- 0.15 mm with ISO (r = 0.96, y = 0.08 + 0.86 x, SEE = 0.14) and 0.18 +/- 0.21 mm with CATH (r = 0.92, y = 0.09 + 0.76 x, SEE = 0.17). The clinical comparison showed reasonable agreement for OD only (r = 0.81, y = 0.26 + 0.81 x, SEE = 0.29). Transformation of an edge-detection algorithm from a digital to a cinefilm-based system can lead to impairment of measurement reliability.

Algorithms↗

Empirical evaluation of a hybrid intelligent monitoring system using different measures of effectiveness.

The validation of a software product is a fundamental part of its development, and focuses on an analysis of whether the software correctly resolves the problems it was designed to tackle. Traditional approaches to validation are based on a comparison of results with what is called a gold standard. Nevertheless, in certain domains, it is not always easy or even possible to establish such a standard. This is the case of intelligent systems that endeavour to simulate or emulate a model of expert behaviour. This article describes the validation of the intelligent system computer-aided foetal evaluator (CAFE), developed for intelligent monitoring of the antenatal condition based on data from the non-stress test (NST), and how this validation was accomplished through a methodology designed to resolve the problem of the validation of intelligent systems. System performance was compared to that of three obstetricians using 3450 min of cardiotocographic (CTG) records corresponding to 53 different patients. From these records different parameters were extracted and interpreted, and thus, the validation was carried out on a parameter-by-parameter basis using measurement techniques such as percentage agreement, the Kappa statistic or cluster analysis. Results showed that the system's agreement with the experts is, in general, similar to agreement between the experts themselves which, in turn, permits our system to be considered at least as skillful as our experts. Throughout our article, the results obtained are commented on with a view to demonstrating how the utilisation of different measures of the level of agreement existing between system and experts can assist not only in assessing the aptness of a system, but also in highlighting its weaknesses. This kind of assessment means that the system can be fine-tuned repeatedly to the point where the expected results are obtained.

Artificial Intelligence↗

Airway wall thickness in cigarette smokers: quantitative thin-section CT assessment.

PURPOSE: To design and validate a dedicated software tool to measure airway dimensions on thin-section computed tomographic (CT) images and to use the tool to prospectively compare airway wall thickness in nonsmokers with normal lung function with that in smokers with and without chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: All subjects gave written informed consent. The study was approved by local ethics committee. With Laplacian of Gaussian algorithm, software was tested in phantom and excised sheep lung fixed in inflation and validated with Bland-Altman analysis. Study prospectively included nine nonsmokers (six women, three men; mean age, 53 years +/- 5.6 [standard error of the mean]) with normal lung function (group 1), seven smokers (three women, four men; mean age, 56 years +/- 5.6) with normal lung function (group 2), and eight smokers (zero women, eight men; mean age, 65 years +/- 4.0) with COPD. Calculations were determined with spirometrically gated CT: For each selected bronchus, the wall area (WA), internal area (IA), airway caliber (sum of IA and WA), and WA/IA ratio were calculated. For each patient, summation of WA to summation of IA (SigmaWA/SigmaIA) ratio, which reflected normalized airway wall thickness, was calculated. Groups were compared by using analysis of variance with generalized linear model and unpaired t test. Pearson correlation coefficient was used to assess correlation between software measurements and pulmonary function test results. RESULTS: Comparison of measurements in phantom and excised sheep lung with algorithm measurements revealed that the latter were reliable and repeatable. In clinical study, SigmaWA/SigmaIA ratio was significantly different among three groups (P < .001). Normalized airway wall thickness and IA were significantly related to lung function test data, including forced expiratory volume in 1 second (r = -0.54, P = .006), specific airway conductance (r = -0.45, P = .03), and forced expiratory flow between 25% and 75% of vital capacity (r = -0.65, P < .001). CONCLUSION: This software provides accurate and reproducible measurements of IA and WA of bronchi on thin-section CT images and demonstrates that in vivo normalized airway wall thickness was larger in smokers with COPD than it was in smokers or nonsmokers without COPD.

Animals↗

Validation of VITEK 2 version 4.01 software for detection, identification, and classification of glycopeptide-resistant enterococci.

We evaluated the ability of the new VITEK 2 version 4.01 software to identify and detect glycopeptide-resistant enterococci compared to that of the reference broth microdilution method and to classify them into the vanA, vanB, vanC1, and vanC2 genotypes. Moreover, the accuracy of antimicrobial susceptibility testing with agents with improved potencies against glycopeptide-resistant enterococci was determined. A total of 121 enterococci were investigated. The new VITEK 2 software was able to identify 114 (94.2%) enterococcal strains correctly to the species level and to classify 119 (98.3%) enterococci correctly to the glycopeptide resistance genotype level. One Enterococcus casseliflavus strain and six Enterococcus faecium vanA strains with low-level resistance to vancomycin were identified with low discrimination, requiring additional tests. One of the vanA strains was misclassified as the vanB type, and one glycopeptide-susceptible E. facium wild type was misclassified as the vanA type. The overall essential agreements for antimicrobial susceptibility testing results were 94.2% for vancomycin, 95.9% for teicoplanin, 100% for quinupristin-dalfopristin and moxifloxacin, and 97.5% for linezolid. The rates of minor errors were 9% for teicoplanin and 5% for the other antibiotic agents. The identification and susceptibility data were produced within 4 h to 6 h 30 min and 8 h 15 min to 12 h 15 min. In conclusion, use of VITEK 2 version 4.01 software appears to be a reliable method for the identification and detection of glycopeptide-resistant enterococci as well as an improvement over the use of the former VITEK 2 database. However, a significant reduction in the detection time would be desirable.

Anti-Bacterial Agents↗

ROCPLOT: a generic software tool for ROC analysis and the validation of predictive methods.

UNLABELLED: Receiver operating characteristic (ROC) analysis is a powerful and widely used technique for assessing predictive methods, yet there are no generic, open-source software tools for this that are freely available. Our ROCPLOT program performs ROC analysis on one or more files of search results (hits) and generates the following: (i) ROC values, giving a convenient numerical measure of method sensitivity and specificity; (ii) ROC plots graphically displaying sensitivity and specificity; (iii) classification plots to aid interpretation of the ROC plots and values; and (iv) a bar chart of the distribution of ROC values. ROCPLOT is generic and flexible: data in multiple hits files can be processed in series or parallel, allowing the results of multiple predictions to be viewed side-by-side or combined. AVAILABILITY: ROCPLOT is freely available for download as part of the European Molecular Biology Open Software Suite, EMBOSS (http://emboss.sourceforge.net/apps/rocplot.html).

Computer Graphics↗