[Cancer pain therapy in palliative care patients: knowledge of prehospital emergency physicians in training. Prospective questionnaire-based investigation]. / Kenntnisse angehender Notfallmediziner über die Tumorschmerztherapie bei Palliativpatienten. Prospektive fragebogenbasierte Untersuchung.

BACKGROUND: Cancer diseases are often associated with acute and chronic pain. Therefore, cancer pain is a symptom frequently reported by palliative care patients with cancer diseases. Prehospital emergency physicians may be confronted with exacerbation of pain in cancer patients. The aim of this study was to evaluate the knowledge of prehospital emergency physicians in training concerning cancer pain therapy. METHODS: A total of 471 prehospital emergency physicians received a questionnaire (period of time: 2007-2009). The questionnaire was prepared for the study ("mixed methods design"). Twenty-four questions concerning cancer pain therapy (response options: scaling, open) were designed. The evaluation was done descriptively according to professional experience, field name and experience in treating patients with cancer as well. RESULTS: A total of 469 participants completed the questionnaire (response rate 99%). On average, 10.8 (SD +5.7, range 2-24) questions were answered correctly. Resident physicians answered statistically significantly more questions correctly than consultants (p=0.02). Only physicians working in internal medicine achieved statistically significantly better results than other disciplines (e.g., surgery; p=0.01). Physicians with professional experience of less than 5 years answered statistically significantly more questions correctly (p=0.004). CONCLUSIONS: The results of this study verify that emergency physicians in training have insufficient knowledge of pain therapy and end-of-life decisions. The data of this investigation suggest that more attention should be paid to education on pain therapy and end-of-life care in medical curricula. Prehospital emergency physicians may thus be better prepared to provide quality care for palliative patients.

The influence of strongly reducing conditions on strong metal-support interactions in Cu/ZnO catalysts used for methanol synthesis.

A systematic series of binary and ternary copper catalysts was investigated using the methanol synthesis reaction at atmospheric pressure. Strong metal-support interactions between copper and zinc oxide induced by strongly reducing conditions were probed by the adsorption of carbon monoxide, which was monitored qualitatively and quantitatively by a combination of microcalorimetry, temperature-programmed desorption experiments and Fourier transform infrared spectroscopy. For the zinc oxide-containing catalysts, the pretreatment in flowing carbon monoxide at 493 K resulted in a severe decoration of the copper metal particles with ZnOx adspecies, whereas after methanol synthesis at 493 K the state of the copper was essentially identical to that seen after hydrogen reduction. Copper was always found to be present in its zero-valent state.

Redox chemistry of Cu colloids probed by adsorbed CO: an in situ attenuated total reflection Fourier transform infrared study.

The IR spectroscopic investigation of both the adsorption of carbon monoxide and the interaction of oxygen and CO on the surface of copper colloids is described for the first time. The copper colloids were produced by pyrolysis of [Cu(OCH(Me)CH(2)NMe(2))(2)] in hot n-hexadecylamine. Upon contact to synthetic air Cu/Cu(x)O core-shell particles are formed. The treatment of these particles with CO results in the reestablishment of pure Cu(0) particles. These results demonstrate that small molecules penetrate the ligand shell of the nanoparticles and reversibly adsorb at the surface without affecting the particle morphology and size distribution.

Monte Carlo-aided dosimetry of a new high dose-rate brachytherapy source.

In this article we introduce a new high-intensity 192Ir source design for use in a recently reengineered microSelectron-HDR remote afterloading device for high dose-rate (HDR) brachytherapy. The maximum rigid length and outer diameter of the new source are reduced to 4.95 and 0.90 mm, respectively, compared to 5.50 and 1.10 mm for the previous source design introduced in 1991. In addition, a smaller diameter and more flexible steel cable are used, allowing the source cable to negotiate smaller diameter catheters or more tortuously curved catheters. Using Monte Carlo photon transport simulation, the complete two-dimensional (2-D) dose-rate distribution is calculated over the 0.1-7 cm distance range and are presented both as conventional 2-D Cartesian lookup tables and in the formalism recommended by the American Association of Physicists in Medicine Task Group 43 (TG-43) Report. The dose distribution of this source is very similar to that of its predecessor, except near the source tip and in the shadow of the cable assembly, where differences of 5%-8% are apparent. The accuracy of various methods for extrapolating beyond the tubulated anisotropy functions to short distances is evaluated. It is demonstrated that linear extrapolation from the anisotropy functions defined by TG-43 accurately (+/- 2%) estimates dose rate at short and long distances lying outside the radial distance range of the original measured data from which the anisotropy and radial dose functions were derived. In contrast, the algorithm used on the vendor's planning system results in large calculation errors at distances less than 5 mm.

Design and dosimetric characteristics of a high dose rate remotely afterloaded endocavitary applicator system.

PURPOSE: An applicator is described for endocavitary treatment of rectal cancers using a high dose rate (HDR) remote afterloading system with a single high-intensity 192Ir source as an alternative to the 50 kVp x-ray therapy contact unit most frequently used in this application. METHODS AND MATERIALS: The applicator consists of a tungsten-alloy collimator with a 45 degree beveled end, placed in a protoscope with an elliptical cross-section. The resultant 3 cm diameter circular treatment aperture, located in the beveled face of the proctoscope, is irradiated by circular array of dwell positions located about 6.5 mm from the applicator surface. This beveled end allows patients with posterior wall tumors to be treated in the dorsal lithotomy position. The dose-rate distributions about the applicator were determined using a combination of thermoluminescent dosimetry (TLD-100 detectors) and radiochromic film dose measurement techniques along with Monte Carlo dosimetry calculations. TLD-100 (3 x 3 x 0.9 mm3 chips) measurements were used to measure the distribution of dose over the proctoscope surface as well as the central axis dose-rate distribution. Relative radiochromic film measurements were used to measure off-axis ratios (flatness and penumbra width) within the treatment aperture. These data were combined with Monte Carlo simulation results to obtain the final dose distribution. RESULTS: The tungsten collimator successfully limits the dose to the tissue in contact with the proctoscope walls to less than 12% of the prescribed dose. These results indicate that the HDR applicator system has slightly more penetrating depth-dose characteristics than the most widely used contact therapy x-ray machine. Flatness characteristics of the two treatment delivery systems are comparable, although the HDR endocavitary applicator has a significantly wider penumbra. Finally, the HDR applicator has a lower surface dose rate (1.5-4 Gy/min of dwell time) compared to 9-10 Gy/min for the x-ray unit. CONCLUSIONS: An applicator system has been developed for endocavitary treatment of early stage rectal carcinoma that uses a single-stepping source HDR remote afterloading system as a radiation source. The advantages of the HDR-based system over x-ray therapy contact units currently used in this clinical application are (a) enhanced flexibility in applicator design and (b) widespread availability of single-stepping source HDR remote afterloading systems.

A new applicator, positionable to the center of tracheobronchial lumen for HDR-IR-192-afterloading of tracheobronchial tumors.

A new bronchial applicator for afterloading irradiation is introduced which can be positioned to the center of the tracheobronchial lumen. The central position in the lumen leads to a clear improvement of dose distribution. The applicator is built on the principle of a coaxial tube. Parts of the outer cover can be expanded to baskets and effect a distance of the radiation source from the bronchial mucosa or tumor surface, and at the same time, expend a relief of extreme contact doses. No obstruction of the respiratory system through the positioning device will be caused. The positionable bronchial applicator seems to be suitable for reducing complications caused through high contact doses and irregular dose distributions and may be able to improve the results of endoluminal radiotherapy.

[Current status of radiotherapy following ablative and breast-sparing treatment of breast cancer]. / Heutiger Stellenwert der Strahlentherapie nach ablativer und nach brusterhaltender Behandlung des Mammakarzinoms.

After a total mastectomy in cases of a high risk of loco-regional recurrence the postoperative irradiation of the chest wall is indicated in the following situations: Inflammatory type of carcinoma, tumor stage T3-T4, extended multifocal and multicentric primary tumor. After radical axillary surgery even in patients with positive nodes irradiation is not necessary except in cases where all axillary nodes are involved or with invasion of the axillary tissue. The supra- and infraclavicular lymph drainage regions caudal to the operated area (clip) should be irradiated with 50 Gy providing both an enlarged or subtotal involvement can be diagnosed. The irradiation of the retrosternal lymph-drainage system with 45-50 Gy is indicated as follows: Medial or central tumor site, extensive involvement of the axillary nodes and advanced stages of the primary tumor (T2-T4). Axillary irradiation alone cannot serve as a substitute for surgery. After segmental mastectomy without postoperative radiotherapy a local failure rate of 30% is to be expected during a 5 year period. After surgery with adjuvant postoperative irradiation the local failure rate can be reduced to about 5%: 50-60 Gy should be applied. In case of an unfavourable histology an additional boost dose is recommended. The objective of breast cancer irradiation is to achieve freedom of loco-regional recurrence. The survival can be improved occasionally after local irradiation, theoretically improvement of survival can be achieved in 7-10% at the most.

[3-D reconstruction of the breast implants from isocentric stereoscopic x-ray images for the application monitoring and irradiation planning of a remote-controlled interstitial afterloading method]. / 3-D-Rekonstruktion von Brustimplantaten aus isozentrischen stereoskopischen Röntgenaufnahmen (ISR) zur Applikationskontrolle und Bestrahlungsplanung einer ferngesteuerten interstitiellen Nachlademethode.

An individual irradiation planning and application monitoring by ISXP is presented for a remote-controlled interstitial afterloading technique using 192Ir wires which is applied in breast-preserving radiotherapy. The errors of reconstruction of the implants are discussed. The consideration of errors for ISXP can be extended to other stereoscopic methods. In this case the quality considerations made by other authors have to be enlarged. The maximum reconstruction error was investigated for a given digitalization precision, focus size, and object blur by patient's movements in dependence on the deviation angle. The optimum deviation angle is about 45 degrees, depending on the importance given to the individual parts and almost without being influenced by the relation between the isocenter-film and the focus-isocenter distances. In case of an optimized deviation angle, a displacement of an implant point of 1 mm leads to a maximum reconstruction error of 2 mm. The dosage is made according to the Paris system. If the circumcircle radius of the application triangle is modified by 1 mm, a dosage modification of 14% will be the consequence in case of very short wires and a small side length. A verification in a phantom showed a positioning error below 0.5 mm. The dosage error is 2% due to the mutual compensation of the direction-isotropic reconstruction errors of the needles the number of which is between seven and nine.

[CT in radiotherapy. Its value in computer-supported 3D-irradiation planning for the breast]. / CT in der Strahlentherapie. Stellenwert bei der rechnerunterstützten 3D-Bestrahlungsplanung der Mamma.

The use and value of CT-directed radiation planning in three planes is discussed. Various modifications for simulation are proposed. In particular, reconstruction for the horizontal position of the sternum is considered.

Silymarin: potent inhibitor of cyclic AMP phosphodiesterase.

Silymarin, the active principle of the Milk Thistle (Silybum marianum Gaertner), is a very potent inhibitor of cyclic AMP breakdown in vitro by a commercial beef heart phosphodiesterase preparation. Its main constituents, silybin, silydianin and silychristin, are 12.66 to 52.06 times more active than theophylline and 0.77 to 3.17 times more active than papaverine in this respect. Using a novel HPLC technique, the enzyme kinetical analysis can be performed much faster than by the classical methods.

[An online monitoring system for the control of field homogeneity in accelerators]. / Ein Online-Monitorsystem zur Kontrolle der Feldhomogenität an Beschleunigern.

For checks and service an online monitoring-system consisting of 10 Si-photoelements will be described. It allows a very simple and fast control of field flatness in therapy-accelerators.

Influence of silymarin and some flavonoids on lipid peroxidation in human platelets.

Sixteen natural phenolics and semisynthetic derivatives thereof, including silymarin, flavonoids, catechines and phenolic acids, together with 6 standard drug substances with anti-inflammatory, antioxidant and peroxide radical scavenging properties have been tested in an in vitro model using human platelets for their inhibitory action against N-ethyl maleimide-induced lipid peroxidation. The malondialdehyde formed during the reaction was estimated by means of the thiobarbituric acid method. In all compounds tested, the inhibitory action was clearly dose-dependent; IC50 values were calculated from the dose-activity curves. The IC50 found ranged from between 1.47 nM and approximately 900 mM.

[Demonstration of ultra-hard X-radiation by means of silicon photo-elements (author's transl)]. / Nachweis ultraharter Röntgenstrahlung mit Silizium-Photoelementen.

Commercial silicon photo-elements were irradiated with 8 MV X-rays and 10 MeV electrons in the linear accelerator SL 75/10, and their usability as monitors and dosemeters was examined. The short circuit current of the photo-elements, which is linear to the transmitted dose rate, was measured with an expressly developed impulse amplifier which is sensitive to electricity. Further examinations as to the energy dependence proved a nearly constant sensitivity within the scope of 1 to 10 MeV. However, there are irradiation damages within this scope, which lead to a decrease of the sensitivity to photo-electricity producing a degeneration rate of 100 to 9 MGy-1. The examination showed on the other hand that, because of their simple measuring principle, the easily reproducible results, and the high sensitivity, the photo-elements can find various applications as monitors with direct display for relative measurements.