Cancer in childhood and supportive care

Wägner, Hans

doi:10.1007/s005200050265

Cited by 6 publications

(3 citation statements)

References 3 publications

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“…Remarkably, this is achieved while preserving tissue functionality following a nominally lethal high dose to normal tissue delivered using micro-beam irradiation. This 'tissue-sparing effect' (Withers et al 1988) makes MRT particularly well-suited for treatment of pediatric brain tumors, potentially causing less damage to the developing central nervous system (Wagner 1999, Mulhern et al 2004, Ribi et al 2005, Laissue et al 2007, Schultke et al 2008. In an intracerebral preclinical trial with 9L gliosarcoma (9GLS), a widely used genetically similar rat brain tumor model that closely simulates glioblastoma multiforme, estimates indicate about a 5-fold advantage in therapeutic index relative to standard broad beam irradiation and over a 10-fold higher normal tissue tolerance (Dilmanian et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Collimator design for spatially-fractionated proton beams for radiobiology research

2016

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Preclinical and translational research is an imperative to improve the efficacy of proton radiotherapy. We present a feasible and practical method to produce spatially-modulated proton beams for cellular and small animal research for clinical and research facilities. The University of Washington (UW) 50.5 MeV proton research beamline hosting a brass collimation system was modeled using Monte Carlo simulations. This collimator consisted of an array of 2 cm long slits to cover an area of 2 × 2 cm(2). To evaluate the collimator design effects on dose rate, valley dose and the peak-to-valley dose ratios (PVDR) the following parameters were varied; slit width (0.1-1.0 mm), peak center-to-center distance (1-3 mm), collimator thickness (1-7 cm) and collimator location along the beam axis. Several combinations of slit widths and 1 mm spacing achieved uniform dose at the Bragg peak while maintaining spatial modulation on the beam entrance. A more detailed analysis was carried out for the case of a slit width of 0.3 mm, peak center-to-center distance of 1 mm, a collimator thickness of 5 cm and with the collimator flush against the water phantom. The dose rate at 5 mm depth dropped relative to an open field by a factor of 12 and produced a PVDR of 10.1. Technical realization of proton mini-beams for radiobiology small animal research is demonstrated to be feasible. It is possible to obtain uniform dose at depth while maintaining reasonable modulation at shallower depths near the beam entrance. While collimator design is important the collimator location has a strong influence on the entrance region PVDRs and on dose rate. These findings are being used to manufacture a collimator for installation on the UW cyclotron proton beam nozzle. This collimator will enable comparative studies on the radiobiological efficacy of x-rays and proton beams.

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Section: Introductionmentioning

confidence: 99%

Collimator design for spatially-fractionated proton beams for radiobiology research

2016

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“…Such is the risk of dysfunctional development of the central nervous system (CNS) from irradiating a tumour in a child's CNS [5][6][7] that paediatric oncologists try to prolong chemotherapy, including intrathecal chemotherapy, either to postpone or to forgo 8 any radiosurgery or radiotherapy, especially for children under the age of 3 years. Multiple parallel micrometreswide planar X-ray beams are used for microbeam radiation therapy (MRT), also known as microbeam radiosurgery, a form of spatially fractionated experimental radiosurgery 9-13 that delivers peak radiation doses up to 50 times those used in other radiosurgeries.…”

mentioning

confidence: 99%

Prospects for microbeam radiation therapy of brain tumours in children to reduce neurological sequelae

Laissue

Blattmann

Wagner

et al. 2007

Develop Med Child Neuro

117

102

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Microbeam radiation therapy (MRT), a form of experimental radiosurgery of tumours using multiple parallel, planar, micrometres‐wide, synchrotron‐generated X‐ray beams (‘microbeams’), can safely deliver radiation doses to contiguous normal animal tissues that are much higher than the maximum doses tolerated by the same normal tissues of animals or patients from any standard millimetres‐wide radiosurgical beam. An array of parallel microbeams, even in doses that cause little damage to radiosensitive developing tissues, for example, the chick chorioallantoic membrane, can inhibit growth or ablate some transplanted malignant tumours in rodents. The cerebella of 100 normal 20 to 38g suckling Sprague‐Dawley rat pups and of 13 normal 5 to 12kg weanling Yorkshire piglets were irradiated with an array of parallel, synchrotron‐wiggler‐generated X‐ray microbeams in doses overlapping the MRT‐relevant range (about 50‐600Gy) using the ID17 wiggler beamline tangential to the 6GeV electron synchrotron ring at the European Synchrotron Radiation Facility in Grenoble, France. Subsequent favourable development of most animals over at least 1 year suggests that MRT might be used to treat children's brain tumours with less risk to the development of the central nervous system than is presently the case when using wider beams.

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“…Major depressive disorder is an illness that can lead to substantial morbidity due to severe functional impairment and risk of mortality because of suicide [26]. Depressive symptoms are associated with a higher-thannormal risk of physical decline and with long-term mortality in older adults [27][28][29]; depression is also a risk factor for coronary heart disease and stroke [30,31], and it is associated with greater use of health care services [32,33].…”

Section: Depressionmentioning

confidence: 99%