[Safety and electromagnetic compatibility in sanitary field]. / Sicurezza e compatibilità elettromagnetica in ambito ospedaliero.

In sanitary field and especially in a hospital, multiple sources of non ionizing radiation are used for diagnostic and therapeutic aims. In sanitary sector both workers and users are present at the same time, and in some cases general population could need higher protection than workers in relationship to the exposition to electromagnetic fields. In order to protect health and safety of patients, general population and workers of hospitals and with the aim to identify, analyze, evaluate and study its level of significance, electrical, magnetic and electromagnetic sources Research Italian project Si.C.E.O. (Safety And Electromagnetic Compatibility In Sanitary Field) was instituted. Target of our research project was to deepen risk of exposition elements with analysis of outdoor (e.g. power lines, transmission cabinets) and indoor (e.g. equipment for physical therapy) sources, located in sanitary structures and to verify the level exposition of workers and common population end the respect of specific regulation, and finally to define technical and organizational measures really useful for protection and reduction of risk.

Mineral alterations in senile osteoporosis.

This research investigates the occurrence of involutional processes of mineral transformation in elderly patients with clinical, radiographic and histological signs of senile osteoporosis. The decreased ability to withstand static and dynamic stresses proved to be associated either with the quantitative reduction in trabeculae or with the altered morphology of hydroxyapatite (HA) crystals. This variation produces a non-homogeneous mineral distribution which leads to a substantial alteration of the system of the stress lines producing mechanical bone behaviour. This altered distribution in mineral density has been attributed to the dynamic loss of balance between osteoblastic and osteoclastic activity; this is believed to be a peculiarity of senile osteoporosis.

Structural modifications and biological compatibility of doped bio-active glasses.

The Raman laser and infrared spectra of doped bio-active glasses of the 45S5 type are presented and discussed. The spectroscopic results show that the doping agents cause the destruction of the basic glass structure and the consequent formation of SiO4(4-) units in the glass network. When the doped glasses have been immersed in a physiological solution (199 medium), a film of calcite forms on the glass surface and this modification is related to the type of doping agent used, decisive for close linking between metal supports and the glass. The presence of doping agents does not prevent the normal growth of the bone onto the surface of doped bioactive glasses. Histological tests show that tissue response to very fine powders of doped glasses increases up to 15 days more or less according to the structural modifications revealed by spectroscopic measurements.

An electrical model of biological tissues undergoing hyperaemia.

Tissue hyperaemia is a physiological consequence of the temperature increase that follows, for example, the absorption of electromagnetic or ultrasound power in clinical diathermy. Diathermy, as well as other physical therapies (for example massotherapy), affects the local blood content of tissues through various mechanisms (vasoconstriction/dilatation, opening/closing of precapillary sphincters). A method for evaluating hyperaemia in superficial and medium-depth tissues has been recently proposed, which is based on four-electrode impedance measurements. A microcirculation model has also been developed to describe the hyperaemic effects of local diathermic therapy. This paper describes an electrical model of the tissues in hyperaemic conditions which allows us to correlate electrical impedance measurements to microcirculation modifications.

Hyperaemia evaluation in clinical diathermy by four-electrode impedance measurements.

The four-electrode electrical impedance measurement technique is proposed for the evaluation of the hyperaemia variation in tissues treated by diathermic therapy. An impedance meter suitable for such measurements is described, and an electrical model of the heated tissues, concerning the impedance variation during diathermy and its relation with hyperaemia, is presented. The occurrence of the substantial contribution of blood to the overall transverse impedance is demonstrated by comparing the experimental results with those arising from a 2D electrical/thermal model of the treated tissues. A two-admittance model is proposed to explain the electrical behaviour of the tissues treated by diathermy. The model allows us to separate the impedance violation due to the temperature dependence of tissue conductivity from that due to the change of tissue blood content. The results of preliminary measurements of tissue impedance on healthy volunteers treated by electromagnetic diathermy are presented and discussed, showing the feasibility of impedance detection of hyperaemia variations inside tissues.

High permittivity patch radiator for single and multi-element hyperthermia applicators.

This paper describes a compact, low-profile patch radiator which is the base element for efficient, small-size applicators suitable for superficial hyperthermia. The design criteria and the technological processes involved are presented. The electromagnetic characteristics of the patch element are outlined, and possible application of the radiator are discussed.

CT-based surgical planning software improves the accuracy of total hip replacement preoperative planning.

The present study is aimed to compare accuracy and the repeatability in planning total hip replacements with the conventional templates on radiographs to that attainable on the same clinical cases when using CT-based planning software. The sizes of the cementless components planned with new computer aided preoperative planning system called Hip-Op and with standard templates were compared to those effectively implanted. The study group intentionally included only difficult clinical cases. The most common aetiology was congenital dysplasia of hip (65.6%). The Hip-Op planning system allowed the surgeons to obtain a preoperative planning more accurate than with templates, especially for the socket. Assuming correct a size planned one calliper above or below that implanted the accuracy increased from 83% for the stem and 69% for the socket when using templates to 86% for the stem and 93% for the socket when using the Hip-Op system. The repeatability of the Hip-Op system was found comparable to that of the template procedure, which is much more familiar to the surgeons. Furthermore, the repeatability of the preoperative planning with the Hip-Op system was consistent between surgeons, independently from their major or minor experience. The study clearly shows the advantages of a three-dimensional computer-based preoperative planning over the traditional template planning, especially when deformed anatomies are involved. The surgical planning performed with the Hip-Op system is accurate and repeatable, especially for the socket and for less experienced surgeons.

Thermal haemolytic threshold of human erythrocytes.

Haemolytic thermal threshold of human erythrocytes has been determined by means of an especially designed microwave apparatus. Temperatures between 50 and 55 degrees C are necessary to produce an initial haemolysis of erythrocytes in the whole blood, while the thermal threshold drops to 37 degrees C for red blood cells suspended in buffered saline. Absorbed energy measurements permit the conclusion that the haemolytic effect is thermal in nature.

Dielectric properties of wood from 2 to 3 GHz.

Many applications of microwave energy to wooden materials have been developed in the last few decades, both for treatment and for diagnostic purposes. All these applications require a reliable estimation of the permittivity of the wood species of interest, which is the physical parameter of crucial importance in the absorption of electromagnetic energy. This paper presents results obtained in the dielectric characterization of five wood species in the frequency range from 2 to 3 GHz, including the ISM frequency of 2.45 GHz. Permittivity was measured by an open-ended coaxial-line probe of new design on wood samples conditioned at several moisture levels. The influence of the natural variability of wood characteristics on the measured permittivity was also investigated by a suitable experimental setup consisting of a poplar table including both sapwood and heartwood regions. Finally, a theoretical discussion on the meaning of a scalar measurement on anisotropic dielectrics is conducted in terms of an isotropic-equivalent permittivity, which is related to the permittivity tensor of the dielectric material.

Exposure of workers to intense RF electric fields that leak from plastic sealers.

This paper presents the results of an environmental investigation in a plastic-ware industry using RF sealers. Environmental measurements have demonstrated the presence of strong electric fields the intensity of which: reaches significant levels from the health-protection point of view only in proximity to the applicators; often exceeds the maximal levels allowed by all standards (including the most permissive) for short duration exposures, especially in the region of the hands. Results of a cross-sectional study on the health of 63 female workers are related to the observed RF exposure. A statistically significant correlation was found to exist between RF exposure and some minor health effects--eye irritation, upper limb paresthesias, and vitreous body disorganization.

The surgical treatment of Rockwood grade III acromioclavicular dislocations.

The conservative or surgical treatment of Rockwood grade III acromioclavicular dislocations continues to be a controversial subject. Thus, the authors report their experience with 52 cases; long-term follow-up was obtained for 40 of these, paying close attention to the preoperative clinical and radiographic evaluation and to the results obtained in order to ascertain whether or not surgical repair is required. The results of surgical treatment, however satisfactory (90% excellent or very good), are nearly the same as those obtained when non surgical treatment is used as reported in the international literature. The authors conclude that the use of surgical treatment must be limited to carefully selected cases, should prolonged conservative treatment fail. Of the three surgical techniques used, temporary stabilization of the acromioclavicular joint using AO wires associated with restoration of the coracoclavicular connections has proven to be more effective than Dall-Miles metal wiring and tangential resection, with a lower incidence of complication.