Biomedical subjects

M Fiebich

Publications and source records attributed to M Fiebich.

9 recordsLinked to original sources

PubMed1997

[Radiologic performance in night and emergency care].

This report deals with radiologic examinations outside official working hours in a German university hospital and the influence of new government regulations. A total of 65,113 radiologic examinations were requested and performed outside official working hours between 1 July 1990 and 30 Juni 1994. The data were analyzed according to the age and sex of this patient population compared with the entire population studied within this 4-year period. Further analysis included the time of the study, the organ systems investigated, and the radiologic technique. About one-third of requests occurred between 16.00 and 20.00 hours on normal working days and, thus, could be taken care of by late shifts. Another third covers the time between 20.00 and 08.00 hours in the morning, which requires inhouse staff (medical and technical). The remainder of the requests occurred during holidays and weekends in the daytime. The most common request in this analysis was for portable chest examination. About 50% of all portable chest examinations were performed outside regular working hours. In all, 17.2% of all requests involved CT and MRT studies. Government regulation did not change the number, technique, and frequency of radiologic examinations outside official working hours.

Adolescent↗

PubMed1995

[Exposure of personnel in interventional radiology].

The surface dose at five typical positions around the patient couch was measured during transjugular intrahepatic porto-systemic stent shunt (TIPSS) interventions for retrospective calculation of staff dose. Additionally, the surface dose was measured on three members of staff (two radiologists and one technician) by placing thermoluminescence (TL) dosimeters directly on the eyebrows, thyroid, sternum, gonads, hands, knees, and feet. The measured surface dose values and the TL dosimeter measurements are used for estimation of effective dose per examination received by personnel. The effective dose for the radiologists is calculated to 25-35 microSv. The maximum number of examinations allowed per year is calculated on the basis of a given yearly dose limit, by looking at organ dose and effective body dose.

Female↗

PubMed1994

[Value of direct radiographic enlargement (DIMA) in early detection of rheumatic inflammatory lesions. Comparative evaluation with high resolution conventional imaging technique].

Rheumatological joint disorders were examined with mammographic film-screen combinations and high-definition microfocal magnification radiography. Our objective was to evaluate the potentials of magnification radiography in diagnosing arthritis by means of interobserver and ROC analysis. The microfocal X-ray unit had a spot size of 20-130 microns; 5-fold magnification was performed. Digital luminescence radiography was employed; digital image processing included simulation of conventional technique and edge enhancement. Eighty radiographs were obtained with conventional and magnification technique. All films were analyzed by five readers. Anatomical and pathological structures were evaluated. The percentage of uncertain findings in magnification radiography was lower compared to conventional radiographs (14% to 26%); in 8% (compared to 19%) the diagnosis of erosions was uncertain. Additionally ROC analysis was carried out. Magnification radiography was significantly (p < 0.03) better than the conventional films.

Arthritis, Rheumatoid↗

PubMed1994

[Documentation with a digital image workstation].

PAC systems are economically advantageous if the use of hardcopies for reporting, archiving and demonstrations is restricted. In place of a film a CRT display has to be used for visualisation. Problems in reporting regarding brightness, contrast, intensity and spatial resolution are described and compared to conventional X-ray films. Results from different studies using CRT displays for reporting are summarised and compared. Some of these studies show reduced diagnostic accuracy if a CRT display is used. This problem may be solved by further developments and by the implementation of software, e.g. computer-aided diagnosis. If the quality of reporting on a CRT display is increased and equivalent to the film, the introduction of a PACS will be qualitatively and economically acceptable.

Computer Systems↗

PubMed1992

[Evaluation of different methods of control of film processing].

In addition to the official control method (DIN 6868), alternative test methods have been developed in the last few years: the "visuelle Methode" by Eder and the "Stuttgarter Modell." The aim of both methods is mainly to increase practicability and economy. The DIN method, however, demonstrates clear benefits, precision, practicability and economy, and it is the only method that allows a trend analysis at small intervals, which is the basis for possible preventive action.

Germany↗

PubMed1992

[Sources of error in the quality assurance of x-ray equipment].

With the introduction of the German industrial protocol for quality assurance of X-ray equipment, everybody using X-ray machines fell into some sort of trap or found some of the procedures misleading. Vigorous discussions were held on every conceivable aspect of this and other protocols, and are still in progress. This paper points out some of the common traps and considers a new type dosimeter, which allows a definite separation of quality assurance of X-ray equipment and of processing and which can also be used in future for quality assurance of digital radiography equipment.

Germany↗

PubMed1991

[Experimental results of the "visual technique"].

This is a study on the applicability of the visual method as an alternative to the present film processing control method according to German DIN standards. It was found that the results are greatly dependent of the kV values. This makes it doubtful whether the method is feasible in its present form. Furthermore, the validity of this method is also limited by the fact that fog and contrast are no longer used as criteria for assessing the development process.

Germany↗

PubMed1991

[A method of estimating doses in digital luminescent radiography].

Digital storage phosphor radiography can produce images of a constant optical density over a wide range of exposure dose by adjusting reading sensitivity. Since overexposed images are not as readily recognized as with the conventional film-screen technique, a formula was designed, which calculates the radiation dose in the film plane from image sensitivity (S factor), latitude (L factor) and average grey value of the region of interest. To verify the formula, 168 measurements with variation of dose, kVp, L factor, S factor and the readout algorithm were performed using the DIGISCAN storage phosphor system (Siemens). The experiments confirmed the validity of the formula for an S factor of below 5000 (values during routine use 50-400). Correlation between dosimetrically measured radiation dose and the calculated dose was 0.997.

Humans↗

PubMed1990

[The visualization of metal implants with digital luminescence radiography].

DLR makes it possible to integrate conventional radiography into digital communication and storage methods (PACS) into radiology. The use of DLR has been compared with conventional film methods in the demonstration of hip prostheses. The high contrast differences at the edge of the metal implant leads to artifacts, which could result in erroneous interpretation. Suitable image manipulation makes it possible, however, to eliminate these artifacts almost completely. DLR leads to an improvement in diagnosis in those complications not specifically related to the prostheses.

Evaluation Studies as Topic↗