Search results for: Michael Bremer

Items from 1 to 20 out of 57 results

article

Comorbidity indexing for prediction of the clinical outcome after stereotactic body radiation therapy in non-small cell lung cancer

Julia Dreyer, Michael Bremer, Christoph Henkenberens

Radiation Oncology > 2018 > 13 > 1 > 1-8

Purpose To determine the prognostic impact of comorbidity and age in medically inoperable early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT) using the age-adjusted Charlson Comorbidity Index (aCCI). Patients and methods Between November 2008 and January 2015, 196 consecutive patients with medically inoperable NSCLC were treated with SBRT at a single...

article

Comparison of relative and absolute rectal dose–volume parameters and clinical correlation with acute and late radiation proctitis in prostate cancer patients

Roman Paleny, Michael Bremer, Daniel Walacides, Silke Mainwaring, more

Strahlentherapie und Onkologie > 2019 > 195 > 2 > 103-112

Purpose To compare relative and absolute dose–volume parameters (DV) of the rectum and their clinical correlation with acute and late radiation proctitis (RP) after radiotherapy (RT) for prostate cancer (PCa). Patients and methods 366 patients received RT for PCa. In total, 49.2% received definitive RT, 20.2% received postoperative RT and 30.6% received salvage RT for biochemical recurrence. In...

article

Temporal and spatial dose distribution of radiation pneumonitis after concurrent radiochemotherapy in stage III non-small cell cancer patients

Mohammed Alharbi, Stefan Janssen, Heiko Golpon, Michael Bremer, more

Radiation Oncology > 2017 > 12 > 1 > 1-7

Background and purpose Radiation pneumonitis (RP) is the most common subacute side effect after concurrent chemoradiotherapy (CRT) for locally advanced non-small cell lung cancer. Several clinical and dose-volume (DV) parameters are associated with a distinct risk of symptomatic RP. The aim of this study was to assess the spatial dose distribution of the RP volume from first occurence to maximum volume...

chapter

Thermal Tolerances

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 325-341

The fundamental information that the designer, construction engineer and telescope operator wants from the preceding chapters are thermal tolerance criteria on which to build a telescope and that can be used to evaluate the thermal performance of an operating telescope. The thermal tolerance criteria derived in this chapter are based on beam pattern calculations explained in Chap. 12, which indicate...

chapter

The Variable Thermal Environment

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 55-83

The local thermal environment interacts with a telescope, or its enclosure, and determines to a large extent the thermal behavior of a telescope. The thermal environment is therefore investigated with the intention to derive global parameters for the design and operation of a telescope and its enclosure. The global parameters are site dependent and dependent on the season, the month, and the day of...

chapter

Radio Astronomy and Radio Telescopes

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 1-12

An astronomical object somewhere in the Planetary System, the Galaxy, a Cluster of Galaxies, or far out in the Universe may generate radio waves by one or the other physical process (a topic of Astrophysics). If the radio emission is generated inside the object, some of the radio waves propagate through the object until they may leave the radio source at its surface (Radiative Transfer). The emitted...

chapter

Beam Formation and Beam Degradation

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 305-324

The elaborate technical efforts in the construction of radio telescopes and communication antennas are undertaken to obtain a clean beam and the best power sensitivity. This merits an explanation of the beam (image) formation of a telescope/antenna, at first hand expected to be perfect, in the end, however, always suffering from some degradation because of technical shortcomings and influences from...

chapter

Radiative Coupling towards Sky and Ground (External View Factor)

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 161-171

A significant radiative coupling can occur between the outer surfaces of a telescope, and enclosure, and the sky and the ground. This radiative coupling is illustrated in Fig. 8.1 for the IRAM 30-m telescope. In the left picture, the telescope is at horizon position so that the upper part of the reflector surface sees the warmer ground while the lower part sees the cooler sky. There exists an up.down...

chapter

Measured Thermal Behaviour of Enclosures

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 263-266

Several radio telescopes for millimeter and sub-millimeter wavelengths and several communication antennas are protected by a radome or an astrodome. The radome is an over-hemispherical enclosure of which the inside climate can be controlled by ventilation or air-conditioned ventilation. The radome is stationary and the Sun illuminates it from a gradually changing direction as explained in Sect. 5...

chapter

Measured Thermal Behaviour of Radio Telescopes

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 173-261

A radio telescope consists of a pedestal, or an alidade or fork, of a BUS connected to the elevation structure or connected to the secondary focus cabin, of panels on the BUS that form the reflector surface, and of a quadripod with the primary focus cabin and subreflector (Fig. 1.1). Not all of these components are in direct thermal contact, but they are all exposed to the variable thermal environment...

chapter

Calculation of Solar Illumination

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 85-106

Solar radiation is the most disturbing external heat source. With solar radiation incident on the ground between approximately 300 and 1000Wm^-2, a white painted telescope or enclosure surface will absorb approximately 50–300Wm^-2. This power will heat up the surface, but part of the absorbed power is radiated back into the environment at infrared wavelengths. The actual amount of incident and absorbed...

chapter

Radio Telescope Constructions in View of Thermal Aspects

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 13-48

A radio telescope operates with good performance if all relevant factors remain stable for a considerable period of time. Adverse influences may arise from gravity, temperature, and wind. They affect the focus, the pointing, the reflector surface, and the path length. Corrections can be made from pointing and focus measurements that may, however, consume a substantial part of the observing time. Telescopes...

chapter

Thermal Model Calculations

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 267-304

Model calculations are made to obtain for certain load cases information on the thermal behavior of a telescope, or a telescope and its enclosure or of a specific structural component. The temperatures predicted from model calculations are used for design and/or operational purposes. Design questions addressed in thermal model calculations may concern the type of insulation required to obtain temperature...

chapter

Optical Telescopes and Enclosures

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 343-346

Although the specific thermal aspects under discussion may be different for a radio telescope and an optical telescope, for instance concerning, on the one hand, the thermal stability of the reflector backup structure and, on the other hand, temperature induced man-made dome seeing, the physics and the treatment of thermal problems is nevertheless in many ways similar. The similarity of thermal issues...

chapter

A Summary and Further Studies

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 347-355

Radio telescopes are built for observations frommeter to sub-millimeter wavelengths (Table 1.1). The steerable telescopes have a parabolic reflector of 10–100–m diameter and the optics can be designed for observations in primary focus, Cassegrainian focus, or Gregory focus (Sect. 2.1). The telescopes have a support, that is, a pedestal, an alidade, or a fork; a reflector backup structure and panels;...

chapter

Telescope Enclosures

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 49-54

The large cm-wavelength telescopes at Jodrell Bank, Effelsberg, Parkes, Green Bank and others are open-air telescopes. The smaller telescopes, and in particular those for short wavelengths, are either closed or placed in an enclosure. A closed telescope is one in which the BUS is covered by the front panels and the rear cladding to prevent direct interaction with the thermal environment, and in some...

chapter

Temperature Measurements and FEM Thermal Deformation Calculations

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 107-121

The temperature (T) and the temperature change with time (∂T/∂t) are the basic parameters in the discussion of the thermal behavior of a structural component. The temperature of a component defines, on the one hand, the heat transfer to other components of the telescope, the enclosure, and the environment, and on the other hand, the thermal expansion of a component and by this a possible force introduced...

chapter

Heat Transfer

Albert Greve, Michael Bremer

Astrophysics and Space Science Library > Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures > 123-159

Heat Transfer is a topic of theoretical physics and engineering physics, covered in many articles, journals, textbooks, and tables. This chapter explains the fundamentals of heat transfer as required for a general understanding of the thermal behavior of large and complex structures, like telescopes and enclosures, and as required for the construction of thermal models of such structures, either for...

book

Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures

Albert Greve, Michael Bremer

Astrophysics and Space Science Library

Radio telescopes as well as communication antennas operate under the influence of gravity, temperature and wind. Among those, temperature influences may degrade the performance of a radio telescope through transient changes of the focus, pointing, path length and sensitivity, often in an unpredictable way. Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures reviews the design...

article

Late radiation side effects, cosmetic outcomes and pain in breast cancer patients after breast-conserving surgery and three-dimensional conformal radiotherapy

Ursula Hille-Betz, Bernhard Vaske, Michael Bremer, Philipp Soergel, more

Strahlentherapie und Onkologie > 2016 > 192 > 1 > 8-16

Background and purpose The purpose of this work was to identify parameters influencing the risk of late radiation side effects, fair or poor cosmetic outcomes (COs) and pain in breast cancer patients after breast-conserving therapy (BCT) and three-dimensional conformal radiotherapy (3D-CRT). Patients and methods Between 2006 and 2013, 159 patients were treated at the Hannover Medical School. Physician-rated...

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INFONA - science communication portal

Search results for: Michael Bremer

Comorbidity indexing for prediction of the clinical outcome after stereotactic body radiation therapy in non-small cell lung cancer

Comparison of relative and absolute rectal dose–volume parameters and clinical correlation with acute and late radiation proctitis in prostate cancer patients

Temporal and spatial dose distribution of radiation pneumonitis after concurrent radiochemotherapy in stage III non-small cell cancer patients

Thermal Tolerances

The Variable Thermal Environment

Radio Astronomy and Radio Telescopes

Beam Formation and Beam Degradation

Radiative Coupling towards Sky and Ground (External View Factor)

Measured Thermal Behaviour of Enclosures

Measured Thermal Behaviour of Radio Telescopes

Calculation of Solar Illumination

Radio Telescope Constructions in View of Thermal Aspects

Thermal Model Calculations

Optical Telescopes and Enclosures

A Summary and Further Studies

Telescope Enclosures

Temperature Measurements and FEM Thermal Deformation Calculations

Heat Transfer

Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures

Late radiation side effects, cosmetic outcomes and pain in breast cancer patients after breast-conserving surgery and three-dimensional conformal radiotherapy

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