Philip Evans

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In the 1980s, companies discovered time as a new source of competitive advantage. In the 1990s, they will discover that time is only one piece of a more far-reaching transformation in the logic of competition. Using examples from Wal-Mart and other highly successful companies, Stalk, Evans, and Shulman of the Boston Consulting Group provide managers with a(More)
A software program, SpekCalc, is presented for the calculation of x-ray spectra from tungsten anode x-ray tubes. SpekCalc was designed primarily for use in a medical physics context, for both research and education purposes, but may also be of interest to those working with x-ray tubes in industry. Noteworthy is the particularly wide range of tube(More)
The penetration characteristics of electron beams into x-ray targets are investigated for incident electron kinetic energies in the range 50-150 keV. The frequency densities of electrons penetrating to a depth x in a target, with a fraction of initial kinetic energy, u, are calculated using Monte Carlo methods for beam energies of 50, 80, 100, 120 and 150(More)
PURPOSE To compare non-target tissue (including left-anterior-descending coronary-artery (LAD)) dosimetry of prone versus supine whole (WBI) and partial-breast irradiation (PBI). METHODS AND MATERIALS Sixty-five post-lumpectomy breast cancer patients underwent CT-imaging supine and prone. On each dataset, the whole-breast clinical-target-volume (WB-CTV),(More)
We have evaluated a 4D ultrasound-based motion tracking system developed for tracking of abdominal organs during therapy. Tracking accuracy and precision were determined using a tissue-mimicking phantom, by comparing tracked motion with known 3D sinusoidal motion. The feasibility of tracking 3D liver motion in vivo was evaluated by acquiring 4D ultrasound(More)
BACKGROUND AND PURPOSE The Normal Tissue Complication Probability (NTCP) for rectum is usually defined for late rectal bleeding. This study calculates NTCP parameter values for additional rectal toxicity endpoints observed in clinical practise. MATERIALS AND METHODS 388 patients from the multicentre MRC-RT01 prostate conformal radiotherapy trial (ISRCTN(More)
The purpose of this study was to investigate methods used to modulate dose distributions in radiotherapy planning, to determine the fundamental features of these and to establish the attainable dose uniformity. Published modulation methods were categorized, and a simple physical model devised to predict the weight of the wedged beam and the relative dose(More)
The survival of children in the South East Thames region, born between 1970 and 1979 and diagnosed as having some form of cerebral palsy was investigated. Of the 732 children studied, 651 (90%) are still alive, and hence cerebral palsy must be regarded as a condition with which people live rather than a condition of which they die. Survival varies(More)
Primary duodenal adenocarcinoma not involving the ampullary region is rare. Our aim was to review the outcome of these patients and determine the factors that affect survival. We performed a retrospective review of all patients with primary, nonampullary duodenal adenocarcinoma at the Cleveland Clinic Foundation from January 1986 through December 1996.(More)
The goal of radiation therapy is to achieve maximal therapeutic benefit expressed in terms of a high probability of local control of disease with minimal side effects. Physically this often equates to the delivery of a high dose of radiation to the tumour or target region whilst maintaining an acceptably low dose to other tissues, particularly those(More)