[Use of patient radiation shielding in diagnostic and interventional radiology]. / Einsatz von Patienten-Strahlenschutzmitteln in der diagnostischen und interventionellen Radiologie.

The use of patient contact shielding provides an opportunity to reduce patient radiation exposure. Recently, the use has been the subject of controversy. The Radiation Protection Committee has published a recommendation on the use of patient radiation shields by considering the recent findings on dose savings but also the risks of incorrect use. In this article, a specification for the more frequently used types of X­ray examination is given, which describes whether and which radiation contact shielding should be used. This is accompanied by a rationale for the use or non-use of patient radiation protection agents. Problems and possible errors are explained, as well as how to deal with special situations such as pregnant women and children.

CT beam dosimetric characterization procedure for personalized dosimetry.

Personalized dosimetry in computed tomography (CT) can be realized by a full Monte Carlo (MC) simulation of the scan procedure. Essential input data needed for the simulation are appropriate CT x-ray source models and a model of the patient's body which is based on the CT image. The purpose of this work is to develop comprehensive procedures for the determination of CT x-ray source models and their verification by comparison of calculated and measured dose distributions in physical phantoms. Mobile equipment together with customized software was developed and used for non-invasive determination of equivalent source models of CT scanners under clinical conditions. Standard and physical anthropomorphic CT dose phantoms equipped with real-time CT dose probes at five representative positions were scanned. The accumulated dose was measured during the scan at the five positions. ImpactMC, an MC-based CT dose software program, was used to simulate the scan. The necessary inputs were obtained from the scan parameters, from the equivalent source models and from the material-segmented CT images of the phantoms. 3D dose distributions in the phantoms were simulated and the dose values calculated at the five positions inside the phantom were compared to measured dose values. Initial results were obtained by means of a General Electric Optima CT 660 and a Toshiba (Canon) Aquilion ONE. In general, the measured and calculated dose values were within relative uncertainties that had been estimated to be less than 10%. The procedures developed were found to be viable and rapid. The procedures are applicable to any scanner type under clinical conditions without making use of the service mode with stationary x-ray tube position. Results show that the procedures are well suited for determining and verifying the equivalent source models needed for personalized CT dosimetry based on post-scan MC calculations.

Outcome of fetuses with gastroschisis after modification of prenatal management strategies : Prenatal management and outcome of gastroschisis.

PURPOSE: To improve the outcome of fetuses with gastrochisis several studies evaluated prenatal predictors. But there are different guidelines established and therefore the prenatal care is not standardized. With our study we wanted to evaluate the outcome of fetuses with gastroschisis after modification of prenatal management strategies at the Department of Obstetrics and Gynecology of the University Hospital Münster. METHODS: In this explorative retrospective study of 39 fetuses with gastroschisis, we compare the clinical outcome between two management groups. In the first group (group 1, n = 14) prenatal indication for delivery was confirmed by a subjective evaluation of the small bowel diameter and the wall thickness without established cut-off values for these parameters. In the second group (group 2, n = 25) certain limits for the small bowel diameter (25 mm) and the wall thickness (2.5 mm) were used for fetal surveillance. RESULTS: Noticeable differences between the two groups regarding birth weight, weight centile, arterial pH, small bowel diameter, wall thickness, adverse bowel condition and re-operations could not be observed. In group 2, delivery was earlier (p = 0.011), and a lower rate of prenatal complications was observed (p = 0.016). CONCLUSION: To avoid adverse prenatal complications we recommend the observation of fetuses with gastroschisis by sonographic monitoring of the small bowel diameter and the wall thickness.

IVEU: IT-based collection and reporting of radiological examination parameters.

In Germany, each site using ionising radiation in human medicine is assigned to a competent medical authority (CMA) for quality assurance. Duties of these CMAs are, e.g. the inspection of medical aspects of the use of X-rays and nuclear medicine at the sites as well as technical quality assurance of X-ray devices. The CMAs themselves have to report the collected exposure values to the ministries and the Federal Office for Radiation Protection. The IVEU (IT-gestütztes Verfahren zur Erfassung von Untersuchungsparametern) Software Framework assists CMAs and radiological departments in collecting and analysing data provided in DICOM headers.

Reducing false alarms of intensive care online-monitoring systems: an evaluation of two signal extraction algorithms.

Online-monitoring systems in intensive care are affected by a high rate of false threshold alarms. These are caused by irrelevant noise and outliers in the measured time series data. The high false alarm rates can be lowered by separating relevant signals from noise and outliers online, in such a way that signal estimations, instead of raw measurements, are compared to the alarm limits. This paper presents a clinical validation study for two recently developed online signal filters. The filters are based on robust repeated median regression in moving windows of varying width. Validation is done offline using a large annotated reference database. The performance criteria are sensitivity and the proportion of false alarms suppressed by the signal filters.

[Is it really not possible to use electronic personal dosimeters in clinical exposure situations?]. / Sind elektronische Personendosimeter in klinischen Expositionssituationen grundsätzlich nicht einsetzbar?

PURPOSE: Due to significant measuring inaccuracies that can occur under certain conditions, the use of electronic personal dosimeters in statutory measurements in X-ray diagnostics is currently legally restricted. The present study investigates the clinically relevant situations in which measurement errors of more then 20 % can be anticipated. MATERIALS AND METHODS: Four series of experiments were made, comparing the results of the electronic personal dosimeter EPD Mk2.3 to those of reference dosimeters (TLDs and diagnostic dosimeters). On the one hand, personal doses have been determined in the routine operation of controlled areas in various departments. On the other hand, measurements on phantoms have been conducted in extreme but realistic situations under radiation protection. Experiments were conducted in unweakened scattered radiation as well as in unattenuated and attenuated direct radiation. RESULTS: The tested electronic personal dosimeter type meets the requirements regarding measurement accuracy for "official" personal dosimeters in all of the examined clinically relevant scattered radiation fields. Only if exposed to radiation directly, an underestimation of the dose can occur and can be greater than 90 %. CONCLUSION: In the range of scattered radiation of diagnostic X-ray equipment, even in pulsed fields, the use of electronic personal dosimeters is reasonable. Considerable measurement errors can only arise in radiation fields that are not realistic under regular conditions and even in connection with most accidents.

Moving nanoparticles with Raman scattering.

We show how to change optically the distance between two protein-linked gold nanoparticles by Raman-induced motion of the linker protein. Rayleigh scattering spectroscopy of the coupled-particle plasmon allows us to compare the inter-nanoparticle distance of individual protein-linked gold nanoparticle dimers before and after surface-enhanced Raman scattering (SERS). We find that low-intensity (50 microW/microm2) laser light in resonance with the nanoparticle-dimer plasmon provokes a change of the inter-nanoparticle distance on the order of 0.5 nm whenever SERS from the proteins connecting the nanoparticles can be observed.

Association of T-786C eNOS gene polymorphism with increased susceptibility to acute chest syndrome in females with sickle cell disease.

Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). A retrospective study was performed to evaluate the role of endothelial nitric oxide synthase (eNOS) gene polymorphisms (E298D and T-786C) in African-American SCD patients. The D298 allele showed no association; the C-786 allele showed a statistically significant association (P = 0.0061) in female ACS cases. Multiple logistic regression analysis showed that relative risk of ACS was 8.695 (P = 0.0076, 95% confidence interval 1.761-42.920) for female carriers of C-786. eNOS T-786C is a gender-specific genetic modifier that is associated with increased susceptibility to ACS in female SCD patients.

Atomic background and EXAFS of gaseous hydrides of Ge, As, Se and Br.

K edge absorption spectra of elements from Ge to Br in gaseous hydrides were measured at the BM 29 station of ESRF with noise level as low as 2x10(-5), so far achievable only on noble gases. The dominant feature of the spectra is the atomic background similar to that of Kr and comparable to it in the quality of detail. Onto the background, a smooth weak EXAFS signal due to the hydrogen neighbors is superposed. For the very simple molecules such as these, its contribution can be calculated ab initio, with exact treatment of the effect of molecular vibrations, so that no best-fit adjustment to the experimental data is necessary. In comparison to the main constituent of the atomic background, i.e. the shake-up absorption edges, the EXAFS signal is of minor importance in HBr with a single H neighbor, but of the same order of magnitude in GeH4.

A study of transferability of atomic background on EXAFS spectra of simple gaseous compounds of As.

From EXAFS spectra of As and As2O3 vapors and arsine gas AsH3 the ab initio calculated structural signal is removed. The remainders comprise small absorption edges due to shake-up channels involving electrons from 3d or 3p subshell. With enhanced resolution, the edges reveal a fine splitting and a varying contribution of resonance channels, due to individual molecular energy-level structure of the samples. On the resolution level appropriate for routine EXAFS analysis the remainders coincide, representing a unique and transferable atomic absorption background for the range of As valence states spanned by the samples.

XAS investigation of Al2O3-coated nano-composite ZrO2.

In order to complement the structural characterisation by high resolution electron microscopy and perturbed angular correlation spectroscopy (PAC) of Al2O3 coated nano-composite ZrO2, XAFS spectra have been acquired and analysed. The electron micrographs showed fringes of a well ordered lattice and well defined crystal faces of the as-produced powder whereas the PAC spectra indicated a strongly distorted short range order. On the basis of the XAFS data, a structural model for the ZrO2 core of the nano-composite ZrO2/Al2O3 with a well ordered Zr lattice and a sevenfold, strongly distorted nearest neighbour oxygen shell is proposed. A smooth temperature dependence without an indication for a phase transformation up to a temperature of 700K has been revealed.

K- and L-edge XAFS determination of the local structure of aqueous Nd(III) and Eu(III).

The short-range coordination of Nd(III) and Eu(III) ions in aqueous solutions has been investigated by means of K-edge x-ray absorption spectroscopy. Experimental data are presented which demonstrate that an accurate determination of the Nd(III) and Eu(III) hydration structural parameters can be obtained from the analysis of the K-edge spectra. It is shown that the large widths of the core hole states do not appreciably reduce the potential structural information of the K-edge EXAFS data. In addition the available k-range of the K-edge spectra is much wider compared to that of the L3-edge which is affected by the presence of double-electron excitations in a more severe fashion.

Liquid Rb micrometric droplets confined in paraffin wax: an X-ray absorption spectroscopy study.

We have performed high-quality X-ray absorption measurements on crystalline (c-Rb) and liquid (l-Rb) Rubidium in the range from 15 K to 320 K. Performing a consistent analysis that takes into account the contribution of the medium range structure, we observe that the l-Rb spectrum is compatible with pair correlation function g(r) previously determined by neutron diffraction experiments. Due to the micrometric size of the liquid droplets we were able to observe a slight undercooling down to 290 K. We were also able to study the details of the very strong multielectron excitations channels in terms of resonances, edges and shake-off features at proper theoretical energy values.

Investigation of undercooled liquid metals using XAFS, temperature scans and diffraction.

Novel techniques and the experimental station for experiments on condensed matter under extreme conditions that have been developed at the BM29 beamline of the European Synchrotron Radiation Facility (ESRF) are described. The experimental setup includes facilities to collect high-quality extended X-ray absorption fine structure (EXAFS) spectra, to perform controlled temperature scans while monitoring the sample absorption for the direct detection of phase transitions, and to collect high-resolution energy-scanning X-ray diffraction (ESXD) data, with recent enhancements through the installation of a two-channel collimator detector system. Facilities for X-ray absorption temperature scans, introduced five years ago, are now exploited for a wide variety of purposes. A method for the measurement of the nucleation rate in undercooled liquids has been proposed recently. All these advances in the experimental setup and techniques, combined with a simple but rigorous X-ray absorption fine structure (XAFS) data analysis scheme for disordered matter, have contributed to make feasible challenging experiments on undercooled liquid matter that were not even conceivable only a few years ago. An example of the application of these methods to undercooled liquid indium (In) is presented.

Infusion of alpha-galactosidase A reduces tissue globotriaosylceramide storage in patients with Fabry disease.

Fabry disease is a lysosomal storage disorder caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). This enzymatic defect results in the accumulation of the glycosphingolipid globotriaosylceramide (Gb(3); also referred to as ceramidetrihexoside) throughout the body. To investigate the effects of purified alpha-gal A, 10 patients with Fabry disease received a single i.v. infusion of one of five escalating dose levels of the enzyme. The objectives of this study were: (i) to evaluate the safety of administered alpha-gal A, (ii) to assess the pharmacokinetics of i.v.-administered alpha-gal A in plasma and liver, and (iii) to determine the effect of this replacement enzyme on hepatic, urine sediment and plasma concentrations of Gb(3). alpha-Gal A infusions were well tolerated in all patients. Immunohistochemical staining of liver tissue approximately 2 days after enzyme infusion identified alpha-gal A in several cell types, including sinusoidal endothelial cells, Kupffer cells, and hepatocytes, suggesting diffuse uptake via the mannose 6-phosphate receptor. The tissue half-life in the liver was greater than 24 hr. After the single dose of alpha-gal A, nine of the 10 patients had significantly reduced Gb(3) levels both in the liver and shed renal tubular epithelial cells in the urine sediment. These data demonstrate that single infusions of alpha-gal A prepared from transfected human fibroblasts are both safe and biochemically active in patients with Fabry disease. The degree of substrate reduction seen in the study is potentially clinically significant in view of the fact that Gb(3) burden in Fabry patients increases gradually over decades. Taken together, these results suggest that enzyme replacement is likely to be an effective therapy for patients with this metabolic disorder.

[The effect of co-existing diseases with cholelithiasis on the course and results of laparoscopic cholecystectomy]. / Wplyw chorób wspólistniejacych z kamica zólciowa na przebieg i wyniki cholecystektomii laparoskopowej.

Six hundred laparoscopic cholecystectomies have been performed in patients with cholelithiasis. Co-existing chronic diseases have been noted in 28% of the operated patients. All these diseases have been known to increase operative risk in classic (open) cholecystectomy (hypertension, coronary disease, cardiac arrhythmias, diabetes mellitus, bronchial asthma). Statistical analysis of the body temperature following laparoscopic cholecystectomy, morbidity and duration of the postoperative hospitalization has revealed that there has been no significant increase in operative risk for laparoscopic cholecystectomy in these patients.

Purification and characterization of multiple forms of the pineapple-stem-derived cysteine proteinases ananain and comosain.

A mixture of ananain (EC 3.4.22.31) and comosain purified from crude pineapple stem extract was found to contain numerous closely related enzyme forms. Chromatographic separation of the major enzyme forms was achieved after treatment of the mixture with thiol-modifying reagents: reversible modification with 2-hydroxyethyl disulphide provided enzyme for kinetic studies, and irreversible alkylation with bromotrifluoroacetone or iodoacetamide gave enzyme for structural analyses by 19F-n.m.r. and electrospray mass spectrometry respectively. Structural and kinetic analyses revealed comosain to be closely related to stem bromelain (EC 3.4.22.32), whereas ananain differed markedly from both comosain and stem bromelain. Nevertheless, differences were seen between comosain and stem bromelain in amino acid composition and kinetic specificity towards the epoxide inhibitor E-64. Differences between five isolatable alternative forms of ananain were characterized by amidolytic activity, thiol stoichiometry and accurate mass determinations. Three of the enzyme forms displayed ananain-like amidolytic activity, whereas the other two forms were inactive. Thiol-stoichiometry determinations revealed that the active enzyme forms contained one free thiol, whereas the inactive forms lacked the reactive thiol required for enzyme activity. M.s. provided direct evidence for oxidation of the active-site thiol to the corresponding sulphinic acid.

[Prevention and treatment of chronic pain in oncologic patients]. / Zapobieganie i leczenie przewleklego bólu u chorych onkologicznych.

The rules of three step therapy of chronic pain in terminal malignant has been presented. The need of priority of non narcotic drugs in retard form, oral or enteral administration and individual schedule out-pacing the occurring of pain has been stressed.