The commercially available X-ray fluoroscopy quality assurance phantom, the Leeds test object TOR18FG, was found to be suitable to assess T-ray image quality in the range (0.1-0.4) THz at a depth of 0.5 cm. Previous to this only custom made phantoms, made especially...
The research relates to possibly replacing 137CsCl irradiators used in radiobiological research involving cells in culture and small animals with an X-RAD 320 Unit (X-ray source[4]) with energies higher than for a typical X-ray irradiator. The objective of this...
BACKGROUND AND PURPOSE: The aim of this study was to compare the efficacy of two different dose-fractionation schedules for radiotherapy of patients with achillodynia. PATIENTS AND METHODS: Between February 2006 and February 2010, 112 consecutive evaluable patients...
PURPOSE: To evaluate the efficacy of low-dose radiotherapy in painful gonarthritis. METHODS: We assessed the medical records of 1037 patients with painful gonarthritis who had undergone low-dose radiotherapy between 1981 and 2008. The subjective patient perception of...
Outcomes for poor-risk localized prostate cancers treated with radiation are still insufficient. Targeting the "non-oncogene" addiction or stress response machinery is an appealing strategy for cancer therapeutics. Heat-shock-protein-90 (Hsp90), an integral member of...
Classical descriptions of tumor physiology suggest two origins for tumor hypoxia; steady-state (diffusion-limited) hypoxia and cycling (perfusionmodulated) hypoxia. Both origins, primarily studied and characterized in murine models, predict relatively small, isolated foci or thin shells of hypoxic tissue interspersed with contrasting oxic tissue. These foci or shells would not be expected to scale with overall tumor size since the oxygen diffusion distance (determined by oxygen permeability and tissue oxygen consumption rate) is not known to vary dramatically from tumor to tumor. We have identified much larger (macroscopic) regions of hypoxia in rat gliosarcoma tumors and in larger human tumors (notably sarcomas and high-grade glial tumors), as indicated by biochemical binding of the hypoxia marker, EF5. Thus, we considered an alternative cause of tumor hypoxia related to a phenomenon first observed in window-chamber tumor models: namely longitudinal arteriole gradients. Although longitudinal arteriole gradients, as originally described, are also microscopic in nature, it is possible for them to scale with tumor size if tumor blood flow is organized in an appropriate manner. In this organization, inflowing blood would arise from relatively well-oxygenated sources and would branch and then coalesce to poorly-oxygenated outflowing blood over distances much larger than the length of conventional arterioles (multi-millimeter scale). This novel concept differs from the common characterization of tumor blood flow as disorganized and/or chaotic. The organization of blood flow to produce extended longitudinal gradients and macroscopic regional hypoxia has many important implications for the imaging, therapy and biological properties of tumors. Herein, we report the first experimental evidence for such blood flow, using rat 9L gliosarcoma tumors grown on the epigastric artery/vein pair.
Cameron J. Koch / W. Timothy Jenkins / Kevin W. Jenkins / Xiang Yang Yang / A. Lee Shuman / Stephen Pickup / Caitlyn R. Riehl / Ramesh Paudyal / Harish Poptani / Sydney M. Evans
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Aim To evaluate efficacy and acute and chronic toxicity of a hypofractionated irradiation schedule in elderly patients with basal cell carcinoma (BCC) of the skin. Materials and methods Between February 2005 and November 2011, 42 retrospectively selected patients...
BACKGROUND AND PURPOSE: To compare the efficacy of two different dose-fractionation schedules for radiotherapy of patients with benign painful shoulder syndrome. PATIENTS AND METHODS: Between February 2006 and February 2010, 312 consecutive evaluable patients were...
Chemoradiation therapy (CRT) prior to surgery is increasingly the standard of care for locally advanced oesophageal cancer. Radiation therapy is important for local tumour control; however, tumour resistance to radiation is a substantial clinical problem. The mechanism(s) of radioresistance are still poorly understood, however, mounting evidence supports a role for microRNA (miRNA) in modulating key cellular pathways mediating response to radiation. Global miRNA profiling of an established isogenic model of radioresistance in oesophageal adenocarcinoma demonstrated a significant downregulation of miR-31 in radioresistant cells, both basally and in response to radiation. Ectopic re-expression of miR-31 significantly re-sensitised radioresistant cells to radiation. miR-31 was demonstrated to alter the expression of 13 genes involved in DNA repair, which is a critical cellular defence against radiation-induced DNA damage. In oesophageal tumours, miR-31 expression was significantly reduced in patients demonstrating poor histomorphologic response to neoadjuvant CRT, whilst expression of the miR-31-regulated DNA repair genes was significantly increased. Our data suggest a possible mechanism for resistance to CRT, potentially via enhanced DNA repair. This study demonstrates, for the first time, a role for miR-31 in modulating radioresistance and highlights the need for further study investigating the potential role of miR-31 as both a predictive marker of response and a novel therapeutic agent with which to enhance the efficacy of radiation therapy.
Niamh Lynam-Lennon, John V Reynolds, Laure Marignol, Orla M Sheils, Graham P Pidgeon and Stephen G Maher
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