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A design goal for current space system is to reduce the mass used to enclose components of the spacecraft. One potential target is to reduce the mass of electronics and its housings. The use of composite materials, especially CFRP (Carbon Fiber Reinforced Plastic) is a well known and vastly used approach to mass reduction. A design goal, cost reduction, has increased the use of commercial (non-space qualified) electronics. These commercial circuits and other components cannot tolerate as high radiation levels as space qualified components. Therefore, the use of standard electronics components poses a challenge in terms of the radiation protection capability of the ADPMS housings. The main goal of this study is to provide insight on the radiation shielding protection produced by different configurations of CFRP tungsten laminates of epoxies and cyanate esters and then to compare them to the protection given by the commonly used aluminum. For a spacecraft operating in LEO and MEO orbits the main components of the space radiation environment are energetic electrons and protons, therefore in our study we will compare the experimental and simulation results of the radiation attenuation of different types of laminates for those particles. At the same time the experimental data has been used to validate the Geant4 model of the laminates, which can be used for future optimizations of the laminate structures. Index Terms--Advanced equipment design, carbon composite laminates, GEANT4, LEO and MEO orbits, low Z-high Z-low Z concept, radiation attenuation, shielding.

Introduction: This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Advanced Methods for Studying Cardiovascular and Respiratory Systems". Objectives; The aim of this study is to assess the reliability of the estimated Nocturnal Heart Rate (HR), recorded through a bed sensor, compared with the one obtained from standard electrocardiography (ECG). Methods: Twenty-eight sleep deprived patients were recorded for one night each through matrix of piezoelectric sensors, integrated into the mattress, through polysomnography (PSG) simultaneously. The two recording methods have been compared in terms of signal quality and differences in heart beat detection. Results: On average, coverage of 92.7% of the total sleep time was obtained for the bed sensor, testifying the good quality of the recordings. The average beat-to-beat error of the inter-beat intervals was 1.06%. These results suggest a good overall signal quality, however, considering fast heart rates (HR > 1 0 0 bpm), performances were worse: in fact, the sensitivity in the heart beat detection was 28.4% while the false positive rate was 3.8% which means that a large amount of fast beats were not detected. Conclusions: The accuracy of the measurements made using the bed sensor has less than 10% of failure rate especially in periods with HR lower than 70 bpm. For fast heart beats the uncertainty increases. This can be explained by the change in morphology of the bed sensor signal in correspondence of a higher HR. [ABSTRACT FROM AUTHOR]

The signal of the dosimetric detector is generally dependent on the shape and size of the sensitive volume of the detector. In order to optimize the performance of the detector and reliability of the output signal the effect of the detector size should be corrected or, at least, taken into account. The response of the detector can be modelled using the convolution theorem that connects the system input (actual dose), output (measured result) and the effect of the detector (response function) by a linear convolution operator. We have developed the super-resolution and non-parametric deconvolution method for determination of the cylinder symmetric ionization chamber radial response function. We have demonstrated that the presented deconvolution method is able to determine the radial response for the Roos parallel plate ionization chamber with a better than 0.5 mm correspondence with the physical measures of the chamber. In addition, the performance of themethod was proved by the excellent agreement between the output factors of the stereotactic conical collimators (4-20 mm diameter) measured by the Roos chamber, where the detector size is larger than the measured field, and the reference detector (diode). The presented deconvolution method has a potential in providing reference data for more accurate physical models of the ionization chamber as well as for improving and enhancing the performance of the detectors in specific dosimetric problems. [ABSTRACT FROM AUTHOR]

Poster: Physics track: Intra-fraction motion management PO-1620: Reconstruction of intra-fractional real-time prostate movement and its effect on dose distribution L. Järvinen, M. Tenhunen, M. Myllykangas, M. Persson, E. Traneus, O. Sjöberg, P. Ekström. [Extracted from the article]

The number of elderly patients with cancer is steadily increasing in developed countries and their treatment is a growing challenge for oncological departments. Anal cancer is the first tumour in which chemoradiotherapy with the intent of organ preservation has largely replaced surgery and is an interesting model of modern multimodal oncological treatment. At the Department of Oncology of the Helsinki University Central Hospital we have treated all patients irrespective of age following the same guidelines if there have been no specific contraindications on the basis of intercurrent diseases. The results suggest that the chemoradiotherapy protocol used in the treatment of anal cancer is reasonably well tolerated in elderly patients and the tumour control is comparable to those achieved in younger patients. After successful cancer therapy the life expectancy in these patients can be very long. [ABSTRACT FROM AUTHOR]

DNA damage induced by low doses of ionizing radiation causes apoptosis, which is partially mediated via the generation of free radicals. Both free radicals and apoptosis are involved in the majority of brain diseases, including stroke, Alzheimer's disease and amyotrophic lateral sclerosis. Because previous studies have shown that tetracycline derivatives doxycycline and minocycline have anti-inflammatory effects and are protective against brain ischemia, we studied whether minocycline and doxycycline or ceftriaxone, a cephalosporin antibiotic with the potential to inhibit excitotoxicity, protect neurons against ionizing radiation in primary cortical cultures. A single dose of 1 Gy significantly increased lactate dehydrogenase release, induced DNA fragmentation in neurons and triggered microglial proliferation. Treatment with minocycline (20 nm), doxycycline (20 nm) and ceftriaxone (1 µm) significantly reduced irradiation-induced lactate dehydrogenase release and DNA fragmentation. The most efficient protection was achieved by minocycline treatment, which also inhibited the irradiation-induced increase in microglial cell number. Our results suggest that some tetracycline derivatives, such as doxycycline and minocycline, and ceftriaxone, a cephalosporin derivative, protect neurons against apoptotic death. [ABSTRACT FROM AUTHOR]

We compared adjuvant chemotherapy-related myocardial damage by antimyosin scintigraphy in patients who received either nine cycles of FEC (fluorouracil, epirubicin and cyclophosphamide) where the doses of epirubicin and cyclophosphamide were escalated according to the leucocyte nadir (group I,n = 14), three cycles of FEC followed by high-dose chemotherapy with alkylating agents (CTCb) given with the support of peripheral blood stem cell transplantation (group II, n = 14), or six cycles of standard intravenous CMF (cyclophosphamide, methotrexate and fluorouracil; group III,n = 8). The cardiac uptake of In-111-antimyosin-Fab (R11D10) antibody was measured and the heart-to-lung ratio (HLR) calculated 8-36 months after the last dose of chemotherapy. Cardiac antimyosin antibody uptake was considerably higher among patients treated with nine cycles of dose-escalated FEC than among those who were treated with three cycles of FEC and high-dose CTCb (HLR, median 1.98; range 1.36-2.24 vs median 1.51; range 1.20-1.82;P < 0.001), or those treated with CMF (median 1.44; range 1.15-1.68;P < 0.001). The difference between groups II and III was not significant (P > 0.1). A linear association was found between the cumulative dose of epirubicin and the cardiac antimyosin uptake (P < 0.001). We conclude that subclinical cardiac damage caused by three cycles of conventional-dose FEC followed by one cycle of high-dose CTCb chemotherapy is small as compared with the damage caused by dose-escalated FEC. [ABSTRACT FROM AUTHOR]