Stephen A Hancock

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PURPOSE To determine the between-algorithm differences in perimetric sensitivity for the Swedish Interactive Threshold algorithm (SITA) Standard, SITA Fast, FASTPAC, and Full Threshold algorithms; to determine the between-subject, between-algorithm differences in the magnitude of the normal variation in sensitivity. METHODS The sample comprised 50 normal(More)
A new novel delivery system for ophthalmic drugs was developed using an antiglaucoma agent Betaxolol Hydrochloride as a model. The new delivery system involved both the binding and release of drug from ion exchange resin particles. Betaxolol was studied in-vitro via a release model analysis. The ocular comfort of Betaxolol was greatly enhanced by reducing(More)
PURPOSE Sub-millimeter accuracy is increasingly important in radiation therapy as the field trends towards highly conformal and high dose-per-fraction therapy. We developed a method for achieving sub-millimeter accuracy in external beam radiation therapy using a surveyor self-leveling laser for precision alignment of radiotherapy vault lasers. METHODS An(More)
Chlorproguanil hydrochloride, dapsone and artesunate are three compounds with anti-malarial properties developed as a triple combination drug product (Dacart™) for the treatment of malarial infections. During long-term stability studies, a degradant was observed which increased with time and had the potential to limit the shelf-life of the product. Through(More)
PURPOSE To develop and demonstrate application of a method that characterizes deviation of linac x-ray beams from the centroid of the volumetric radiation isocenter as a function of gantry, collimator, and table variables. METHODS A set of Winston-Lutz ball-bearing images was used to determine the gantry radiation isocenter as the midrange of deviation(More)
Analytical methods for determining the manufacturing process of tablet dosage forms have not been previously reported. The use of surface analysis techniques in particular X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ionization Mass Spectrometry will be described and a model proposed which allows the prediction of the route of manufacture(More)
PURPOSE Methods in common use for MLC leaf position QA are limited to measurements relative to an arbitrary reference position. The authors previously presented an EPID-based method for efficiently testing accuracy of leaf position relative to the mechanical isocenter for MLC with backup jaws. The purpose of this work is to extend that method to the general(More)
The hallmarks of severe meningococcal sepsis include the rapid onset of shock, purpuric rash, and metabolic derangement, in particular, hypocalcemia. The severe ecchymoses and purpura associated with meningococcal sepsis are usually attributed to acute thrombotic episodes, attributable to the associated procoagulation disorder. An alternative explanation(More)
This presentation takes a broad view of the meaning of quality in radiation therapy, with a focus on the role of the physicist in the pursuit of quality. The strategic approaches to the pursuit of total quality in radiation therapy draw from the fields of philosophy, industrial engineering, behavioral science, mathematical biology, and neuroscience. The(More)