Brendan McClean

Learn More
Much evidence now exists regarding radiation-induced bystander effects, but the mechanisms involved in the transduction of the signal are still unclear. The mitogen-activated protein kinase (MAPK) pathways have been linked to growth factor-mediated regulation of cellular events such as proliferation, senescence, differentiation and apoptosis. Activation of(More)
PURPOSE To determine dosimetric properties of unflattened megavoltage photon beams. MATERIALS AND METHODS Dosimetric data including depth dose, profiles, output factors and phantom scatter factors from three different beam qualities provided by Elekta Precise linacs, operated with and without flattening filter were examined. Additional measurements of(More)
There is much evidence supporting the existence of bystander effects in cells that were never exposed to radiation. Directly irradiated cells and bystander cells can communicate with each other using gap junctional intercellular communication or by releasing soluble factors into the surrounding medium. Exosomes and microvesicles are also known to mediate(More)
PURPOSE The aim of this study was to elucidate the sequence of very early bystander signalling events and to determine the role of the different signalling molecules in both the production of the bystander signal and the response to this signal. MATERIALS AND METHODS Human keratinocytes (HaCaT cell line) were irradiated (0.005, 0.05 and 0.5 Gy) using a(More)
PURPOSE The aim of this study was to compare levels of apoptosis, necrosis, mitotic cell death and senescence after treatment with both direct radiation and irradiated cell conditioned medium. MATERIALS AND METHODS Human keratinocytes (HaCaT cell line) were irradiated (0.005, 0.05 and 0.5 Gy) using a cobalt 60 teletherapy unit. For bystander experiments,(More)
The use of Raman spectroscopy to measure the biochemical profile of healthy and diseased cells and tissues may be a potential solution to many diagnostic problems in the clinic. Although extensively used to identify changes in the biochemical profiles of cancerous cells and tissue, Raman spectroscopy has been used less often for analyzing changes to the(More)
PURPOSE The use of radiotherapy fields smaller than 3 cm in diameter has resulted in the need for accurate detector correction factors for small field dosimetry. However, published factors do not always agree and errors introduced by biased reference detectors, inaccurate Monte Carlo models, or experimental errors can be difficult to distinguish. The aim of(More)
The bystander effect describes radiation-like damage in unirradiated cells either in the vicinity of irradiated cells or exposed to medium from irradiated cells. This study aimed to further characterize the poorly understood mitochondrial response to both direct irradiation and bystander factor(s) in human keratinocytes (HPV-G) and Chinese hamster ovarian(More)
PURPOSE Flattening filters (FFs) have been considered as an integral part of the treatment head of a medical accelerator for more than 50 years. The reasons for the longstanding use are, however, historical ones. Advanced treatment techniques, such as stereotactic radiotherapy or intensity modulated radiotherapy have stimulated the interest in operating(More)
BACKGROUND AND PURPOSE A dosimetric intercomparison of brachytherapy remote afterloading units in Ireland, Scotland and the North of England has been carried out involving 9 radiotherapy centres, and sampling 5 HDR and 6 LDR units. MATERIALS AND METHODS Absolute calibrations have been performed in air on both HDR and LDR sources. The results are expressed(More)