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Biomedical subjects

M Pfeiler

Publications and source records attributed to M Pfeiler.

17 recordsLinked to original sources
PubMed1992

[The functionality and safety of medical electronic products--standardization in a troubled area of conflicting demands].

First, the paper deals with the fundamental importance of standardisation to manufacturers, users and experts; the special demands made by medical engineering on safety and function are outlined clearly and in detail. The application and significance of standards for the development, testing and approval of medical technical systems are illustrated by means of a unit for the extracorporeal disintegration of renal calculi (lithotripsy), and the principle, technology and use of such a unit are discussed. The paper concludes with the prospects for further development of medical engineering and possible consequences for standardisation work. At the same time, the increasing use of software is addressed in particular. Finally, the present work on standards and directives for Europe in 1992 is referred to once again. With reference to the forthcoming standardisation tasks, with hardly increasing resources, an appeal is made for their optimum use to achieve truly international standardisation.

Electronics, Medical↗
PubMed1991

Treatment of the Dunning prostate rat tumor R3327-AT1 with pulsed high energy ultrasound shock waves (PHEUS): growth delay and histomorphologic changes.

We are interested in the interaction of pulsed high energy shock waves (PHEUS) on soft tissues treated in situ to evaluate its potential for therapeutic use. The experimental apparatus built by us was adapted from a lithotripter designed for clinical use. For the present studies we used the R3327-AT1 Dunning prostate tumor growing s.c. in the thigh of Copenhagen rats. The treatments consisted of four groups of eight animals each who received 500 or 2000 pulses at 1 or 5 Hz. Sham-treated tumor bearing animals served as controls (n = 11). During each PHEUS treatment, petechial bleeding of the skin at the point of entry and exit of sound appeared. Sonication at a repetition rate of five Hz seemed to induce more macroscopic damage in terms of hematomas and skin effects. The cytotoxic effects of PHEUS to tumor tissue were sufficient to induce a significant delay (p less than 0.05) in tumor growth but no clear-cut dose relationship was established. Histological studies revealed widespread early rupture of the fine vasculature with extravasation of erythrocytes. By 72 hr., in PHEUS treated tumors, a large necrosis was seen within the central zone which was never observed in sham-treated tumors. Our results clearly indicate that PHEUS has a cytotoxic potential. The observation of a rapid onset of hemostasis, stark hemorrhage and necrosis in the treatment field would suggest that vascular damage is an important contributing factor.

Animals↗
PubMed1983

[Computed tomography--basic principles and outlook for related procedures].

The computerized X-ray tomography uses for the information of the images besides a highly developed computer technology a special CT-algorithm, i.e. preprocessing of detected "projections", their "high-pass" convolution and back-projection. The diagnostic success of computerized X-ray tomography gave rise to the investigation of other carriers of information besides X-radiation for the production of cross-sectional pictures using CT reconstruction principles. Examples are: Emission-CT, Proton-CT, Nuclear Magnetic Resonance CT, Ultrasound-CT, Impedance-CT and Mikrowave-CT. This paper gives a review of such methods, their basis properties and an estimation of their capabilities for medical application. This discussion is opened by a summary of the basis CT principles.

Humans↗