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A dynamic quality control phantom for radionuclide cardiology.

A three-dimensional dynamic cardiac phantom suitable for quality control of equilibrium gated nuclear cardiographic procedures is described. Its flexible microprocessor based design provides an absolute standard for ejection fraction determination, ventricular volume quantitation, and physiologically gated single photon emission computed tomography. The cost of the phantom is comparable to that of commercially available phantoms suitable for ejection fraction quality control alone.

Heart↗

Disk diffusion quality control guidelines for Haemophilus susceptibility tests using cefdinir, CI-960, fleroxacin, temafloxacin, and trospectomycin.

A multilaboratory study to determine disk diffusion quality control ranges for Haemophilus influenzae ATCC 49247 and five investigational drugs was performed. Multiple lots of Haemophilus Test Medium and antibiotic disks were used for replicate testing in conformance with the recommendations of the National Committee for Clinical Laboratory Standards. Quality control disk zone diameter ranges were proposed for cefdinir, CI-960, fleroxacin, temafloxacin, and trospectomycin.

Anti-Bacterial Agents↗

Pharmaceutical quality control of radiolabeled monoclonal antibodies and their fragments.

Monoclonal antibodies are immunochemical reagents whose functional integrity is critical to their clinical applications. Quality control through each stage from antibody production through purification and radiolabeling is necessary if radiopharmaceuticals with reproducible in vivo characteristics are to be achieved. This article describes some of the quality control methods that can be used during developmental and clinical stages of evolution of these radiopharmaceuticals.

Antibodies, Monoclonal↗

Quality control in the MRFIT local screening and clinic laboratory.

Quality control was emphasized in the screening and clinic laboratory during the early stages of the trial to cover all aspects of screening, and in the later stages to cover local testing used to monitor the participant in the clinic and to guarantee collection of valid specimens to be shipped to the Central Laboratory. Special attention throughout the trial was focused on techniques for collection of specimens, since it was recognized that analytical results could not be better than the quality of the specimens. Training courses, on-site visits, and newsletters were used to sensitize the staff of the clinic laboratory about the necessity to follow protocol. Any monitoring evidence of carelessness, use of deteriorated supplies, failure to follow safety rules, and deviation from directions in the MRFIT Manual of Operations resulted in memoranda from the Coordinating Center or the Central Laboratory.

Cholesterol↗

Accuracy in clinical laboratories participating in regional quality control programs.

Few studies have assessed analytic bias (accuracy) in clinical chemistry laboratories. Using the data base of a large regional quality control program, we studied, during a six-year period, analytic bias of participant "all-methods" results, as well as selected commonly used individual methods, for calcium, cholesterol, glucose, potassium, and sodium. Analytic bias was assessed by comparison with "benchmark" measurements by United States Bureau of Standards definitive methods and/or United States Centers for Disease Control clinical reference methods. The all-methods bias at selected clinically relevant analyte levels was +0.1% at 10 mg/dL for calcium; -0.7% for cholesterol at 200 mg/dL; +4.5% for glucose at 120 mg/dL; +0.5% for potassium at 4 mmole/L; and 0% for sodium at 145 mmole/L. There was sufficient agreement between benchmark and participant all-methods results for these analytes to suggest that the all-methods results may be useful analytic bias benchmarks in future regional quality control programs that use similar lyophilized human serum pools.

Blood Glucose↗

Quality control of manual visual field examination by computer simulation.

Quality control of manual visual field examination is impaired because the process is difficult to monitor, and because examiners have minimal formal training and supervision, and are subject to rapid turnover. Computer simulation can be used both to teach perimetry and to provide a reference standard against which performance may be measured.

Community Health Services↗

Quality control in cytopathology. A system for simultaneous monitoring of accuracy and education and for proficiency testing.

Because of its very nature, cytopathology has not lent itself well to quality control. At the University of North Carolina, we practice an internal quality control system based on peer review, interprofessional dialogue and utilization of follow-up information. Recently reported cytology specimens are rescreened and correlated with related surgical specimens. This review is summarized in a weekly conference, at which retrospective accuracy judgments are made for each case under the supervision of the medical director and head cytotechnologist. Diagnostic accuracy is thus monitored. Accuracy is also improved since education is simultaneously monitored. A practical proficiency-testing program built into this system is described.

Allied Health Personnel↗

Spatial and temporal response characteristics of ionization chambers used in diagnostic radiology for exposure measurements and quality control.

The temporal and spatial (partial volume) response characteristics of ionization chambers used for measuring radiation exposures in x-ray quality control (QC) programs were evaluated. Five ionization chambers were evaluated using a pencil beam scanning x-ray source and a conventional radiographic system. The spatial response was determined by recording the exposure during scanning of the pencil beam or in increments using a slitted lead sheet on a conventional x-ray system. The temporal response was determined by recording x-ray wave forms using the different ionization chambers. The effects of partial volume irradiation of the chambers makes them unsuitable for use under these conditions, except those designed for exposure measurements in computed tomography. The temporal response of many chambers resembles that of a typical resistive-capacitive circuit, making them unsuitable for exposure time measurements or x-ray wave form evaluation. The appropriate ionization chamber must be selected for exposure measurements and quality control in diagnostic radiology.

Equipment Design↗

Evaluation of a new body composition phantom for quality control and cross-calibration of DXA devices.

This study evaluated a new body composition phantom and its use for quality control and cross-calibration of dual-energy X-ray absorptiometry (DXA) instruments for measurements of body composition. We imaged the variable composition phantom (Lunar, Madison, WI) on eight different DXA devices. Deviations of up to 7% fat were observed when we compared the percent fat values measured by the different devices with the nominal values provided by the manufacturer. Absolute precision error of percent fat measurements for the phantom ranged from 0.6 to 0.8%. The phantom's percent fat values were also compared with whole body composition measurements from 130 female and male volunteers. The phantom detected differences in percent fat values that were similar to those found by comparing in vivo measurements with values from different DXA scanner models from the same manufacturer. When comparing different models of scanners from different manufacturers, such as the Hologic QDR-4500 and the Lunar DPX-IQ, the phantom showed a different relationship than was seen for patients. Therefore, corrections or comparisons based on the phantom data alone would be incorrect. In conclusion, the Lunar variable composition phantom is capable of accurately measuring the fat calibration of DXA devices and may be suitable for cross-sectional cross-calibration between scanners from the same manufacturer; however, for comparison of DXA scanners from different manufacturers, in vivo cross-calibration is still the only accurate method. The phantom may be used in longitudinal quality control to verify an instrument's temporal stability.

Absorptiometry, Photon↗

Hospital equipment management, maintenance and quality control in the Netherlands.

Before 1970, equipment maintenance and quality control in Dutch hospitals were not organised. There was little or no cooperation between physicians, hospital employees and instrument suppliers. Health services which are not nationalised are funded by non-profit making foundations. There were few regulations covering the supply and maintenance of equipment. However, the country is small enough for there to be considerable contact between instrument engineers. In the past eight years a new situation has arisen where rules are being formulated based on collective experiences. A better understanding has to grow between physicians, nurses and engineers, of each others' needs and possibilities in relation to the use of instruments and the necessity of maintenance. To keep quality on an acceptable level, exaggeration in one direction or another has to be avoided.

Equipment and Supplies, Hospital↗

[Quality control of surgical care (author's transl)].

Based on studies carried on for more than ten years, various methods for voluntary quality control of surgical care are proposed. Besides short-term measures (e.g., "strategy of therapy"), a long-term pilot study would permit detection of defects and errors in surgical care through the recording of comparable data. An organization (similar to the Dutch "Concilium chirurgicum") should sponser visitations to various surgical centers. These two, strictly voluntary measures should form the basis for quality control that boots self-esteem of surgeons and does away with the need for state-sponsored measures.

Education, Medical, Continuing↗

[Quality control in Austrian hospitals--results of evaluation].

The revision of the federal hospital act (Nov. 11, 1993; BGB1 Nr. 801/93) intends the introduction of an internal quality control as well as comparisons between different hospitals. For the application fo these constitutional requirements, the state governments had to develop laws being the basis for the hospital management to implement quality assurance. To support the introduction of a systematic quality control, the federal ministry of health published a guideline for quality assurance which was made available to all hospitals. Now, a questionnaire in all Austrian hospitals was designed to evaluate the progress and the specific ways of implementations as well as the possible need for action in the future.

Austria↗

Acceptance tests and quality control (QC) procedures for the clinical implementation of intensity modulated radiotherapy (IMRT) using inverse planning and the sliding window technique: experience from five radiotherapy departments.

BACKGROUND AND PURPOSE: An increasing number of radiotherapy centres is now aiming for clinical implementation of intensity modulated radiotherapy (IMRT), but--in contrast to conventional treatment--no national or international guidelines for commissioning of the treatment planning system (TPS) and acceptance tests of treatment equipment have yet been developed. This paper bundles the experience of five radiotherapy departments that have introduced IMRT into their clinical routine. METHODS AND MATERIALS: The five radiotherapy departments are using similar configurations since they adopted the commercially available Varian solution for IMRT, regarding treatment planning as well as treatment delivery. All are using the sliding window technique. Different approaches towards the derivation of the multileaf collimator (MLC) parameters required for the configuration of the TPS are described. A description of the quality control procedures for the dynamic MLC, including their respective frequencies, is given. For the acceptance of the TPS for IMRT multiple quality control plans were developed on a variety of phantoms, testing the flexibility of the inverse planning modules to produce the desired dose pattern as well as assessing the accuracy of the dose calculation. Regarding patient treatment verification, all five centres perform dosimetric pre-treatment verification of the treatment fields, be it on a single field or on a total plan procedure. During the actual treatment, the primary focus is on patient positioning rather than dosimetry. Intracavitary in vivo measurements were performed in special cases. RESULT AND CONCLUSION: The configurational MLC parameters obtained through different methods are not identical for all centres, but the observed variations have shown to be of no significant clinical relevance. The quality control (QC) procedures for the dMLC have not detected any discrepancies since their initiation, demonstrating the reliability of the MLC controller. The development of geometrically simple QC plans to test the inverse planning, the dynamic MLC modules and the final dose calculation has proven to be useful in pointing out the need to remodel the single pencil beam scatter kernels in some centres. The final correspondence between calculated and measured dose was found to be satisfactory by all centres, for QC test plans as well as for pre-treatment verification of clinical IMRT fields. An intercomparison of the man hours needed per patient plan verification reveals a substantial variation depending on the type of measurements performed.

Humans↗

Proposed interpretive criteria and quality control parameters for ofloxacin susceptibility testing of Neisseria gonorrhoeae.

A multilaboratory study designed to determine the in vitro susceptibility criteria and quality control parameters for ofloxacin against Neisseria gonorrhoeae was conducted according to the guidelines of the National Committee for Clinical Laboratory Standards. Proposed susceptibility breakpoints are MICs of less than or equal to 0.25 microgram/ml for the agar dilution test and greater than or equal to 31 mm for the disk diffusion test. A category for resistance could not be defined. Proposed acceptable quality control MICs for N. gonorrhoeae ATCC 49226 and Staphylococcus aureus ATCC 29213 range from 0.004 to 0.03 microgram/ml and 0.25 to 1.0 microgram/ml, respectively. With 5-micrograms ofloxacin disks, acceptable inhibitory zone diameters for S. aureus ATCC 25923 and the N. gonorrhoeae control strains range from 22 to 27 mm and 43 to 51 mm, respectively.

Drug Resistance, Microbial↗

Methods of measuring susceptibility of anaerobic bacteria to trovafloxacin, including quality control parameters.

Three methods approved by the National Committee for Clinical Laboratory Standards for testing the susceptibility of anaerobic bacteria were used to evaluate the fluoroquinolone, trovafloxacin. The methods gave essentially comparable results with 126 anaerobes and with three quality control strains. A collaborative study defined the quality control range for trovafloxacin MICs. Trovafloxacin had good in vitro activity against the more common anaerobes (MIC 90 < = or 2.0 micrograms/ml).

Anti-Infective Agents↗

A quality-control system for the general urinalysis laboratory.

Sixteen quality-control products were prepared for general urinalysis testing. Empirically derived formulations simulating the variety found in clinical material monitored the routine analyses for pH, specific gravity, protein, glucose, ketone, and hemoglobin. Formalin-fixed erythrocytes, leukocytes, casts, crystals, and other particulates were added for qualitative identification of the formed sediment. Analytic results outside of the acceptable range were often due to errors in technic or subjective interpretation; re-education of individual personnel was followed by a decrease in the error rate over the first five months of the program.

Clinical Laboratory Techniques↗

[Quality control in peripheral vascular surgery].

Indications and modalities of quality control in infrainguinal bypass surgery are reviewed and discussed. A concept and an armamentarium for its practical use are presented. The majority of graft occlusions occur during the first postoperative year. Most failures in the first month are due to technical errors. Many of these can be detected by intraoperative completion control, and immediately repaired. This contributes to improved graft patency rates. In the further course, myo-intimal hyperplasia accounts for most graft stenoses and occlusions. If stenoses are detected and dilated before occlusion occurs, long-term patency is but little impaired. Conversely, patency rates are clearly inferior in grafts following thrombectomy or thrombolysis. Therefore, identification of failing grafts and avoidance of failure are the objectives of surveillance. We have followed routinely a surveillance program since 1991. During surgery, grafts were controlled by completion angiography. Arterial pressures were measured and the ankle-brachial index calculated postoperatively and 1, 3, 6 and 12 months after surgery. In addition, a number of grafts were followed by duplex sonography. Data were stored in an electronic data base featuring several interactive functions. E.g., ankle-brachial and duplex-sonography indices were calculated and rated automatically according to current criteria. Secondary patency after 18 months was 86 per cent in suprageniculate femoro-popliteal bypass grafts, 84 per cent in infrageniculate and 65 per cent in crural (n = 19/23/27).

Blood Vessel Prosthesis↗

[Artificial nutrition in hospitals: general principles of quality control].

Sterile pharmaceutical preparations must be supplied to clinical wards; their high degree of safety is given by hospital pharmacists who are responsible for quality control of these preparations. Various considerations on the choice of protocol are suggested. Good manufacturing practice is to carry out quality controls at every stage of production of total parenteral nutrition fluids. However, these controls are made difficult by the poor equipment of hospital pharmacies and by the absence of specific pharmaceutical monographs. The selected protocol involves: preliminary controls, which determine the practicability of the suggested formulation, as well as its expiration date: amino acid determinations using liquid chromatography, electrolyte analysis and concentration, pH, evolution of particle size in fat emulsion according to storage conditions, choice of plastic container; microbiological controls: every two months and every time the pharmaceutical staff changes; moreover, a search for bacterial endotoxins using a chromogenic substrate (LAL technique) with "microstrips" is suggested; a sample from each admixture is kept under refrigeration for 15 days; controls during fabrication to check, at the end of the process, if good manufacturing practices have been realized: microbiological sampling of the working area and elaboration of a written procedure; control after fabrication of each nutrient admixture: determination of various elements such as sodium, potassium and dextrose in a 5 ml sample. These assays enable the checking of high standards of fabrication. Hospital pharmacies, despite their reduced equipment, can answer by these procedures to the physicians' needs and supply sterile TPN meeting pharmaceutical standards.

Electrolytes↗