Neurological modelling of the vision system with relevance to an application for improved detection of early breast cancer

University of Technology, Sydney. Dept. of Health Sciences.Detection and recognition of early signs of breast cancer when represented by cancer-related types of microcalcifications, are key requirements in breast screening mammography. Edge detection plays a vital role not only in observing detail in lesions with microcalcifications but also for the perception of often weakly defined stellate tumours. Mammograms are read at around 60 to 80 per hour. We develop a neurological based functional model for edge responses of on-centre (Cʟ) and off-centre (Cᴅ) groups of neurons in the early vision physiology, from the retina to the striate visual cortex V1. It is shown that the responses of the resulting differential equations at the retina and at V1 are of the Lotka-Volterra (LV) type. They display two important properties: consistency with the retinotopic property of early vision physiology and susceptibility to the 1/ƒ type noise for a stochastic resonance (SR) effect on the edge responses based on Cʟ and Cᴅ interactions. Computer simulations of repeated cycles of the LV responses when 1/ƒ noise was incorporated into the interaction terms of the equations, showed an increased probability of occurrences of closely coupled small values of Cʟ and Cᴅ. This indicated an underlying stochastic resonance effect. Such occurrences suggested a method for improved edge detection for "low observables" and improved detail in microcalcification regions in mammograms. An experimental viewing system using a dynamic polaroid and eyepieces with colour filters was developed to provide 1/ƒ noise to test this hypothesis. It provided for the resulting Cʟ and Cᴅ inputs from the left and right eye of an observer to interact in the V1 laminae. Using a set of 30 microcalcification region of interest images, tests were conducted in real-time readings with five observers, each at two different times. There was double blind randomisation of the sequence of images in addition to the order of presentation of "with" and "without noise". The experience levels of the observers ranged from a low level working with technical images (not mammograms) to a high level experienced radiologist. An initial series of 300 observations using ratings of detail quality (1 to 5) showed significance for an improved effect (p<0.05). A second series of 300 observations for a more stringent test with improved symmetrical experimental design of the equipment and alternative-forced-choice for observers to reduce subjectivity, showed a "trend to significance" (p<0.1). Observers with more experience had better performance in the tests (p∼0.07). Intra-observer variability was consistently good compared with inter-observer results. A parameter in the L-V equations which is related to observer attention, coupled with a spatial search requirement, may be part of the inter-observer variability. The findings also have implications for the training of radiologists in reading mammograms in real-time screening. Recent developments in spectral properties of photonics materials may provide a simple implementation of the principles developed in the thesis

Interacting Psycho-economic Expectations Ratios with Equity/debt Realities Suggests a Crisis Warning Method

The recent April 2011 meeting of the G20 countries considered possible development of a global early warning system to avoid any future financial crisis. Psycho-economic factors are strong drivers of greed, fear and non-rational behavior and experience shows that they should not be excluded from such a project. Rational, logical behavior for attitude and actions has been an assumption in most financial models prior to the advent of the 2008 crisis. In recent years there has been an increasing interest in relating financial activity to phenomena in physics, turbulence, neurology and recent fMRI experiments show that cortical interactions for decisions are affected by previous experience. We use an extension of two Lotka-Volterra (LV) interactive equations used in a model for the 2008 crisis but now with fluctuation theory from chemical physics to interact the two previously used heterogenous interacting agents, the psycho-economic ratio CE of investor expectations (favourable/unfavourable) and the reality ratio of equity/debt. The model provides a variable, M, for uncertainties in CE arising from the ability of the economy to affect the financial sector. A condition obtained for keeping rates of change in M small to avoid divergence of spontaneous fluctuations, provides a quantifiable time dependent entity which can act as a warning of impending crisis. The conditional expression appears to be related to an extension of Ohm's law as in a recently discovered "chip" and memory; the memristor. The possible role of subthreshold legacies in CE from the previous crisis appears to be possible and related to recent neurological findings

Exercise medicine in cancer care

Background Every four minutes, an Australian is diagnosed with cancer. Early detection and effective treatment means that many of these people are living with the side effects of cancer and its treatment for numerous years. Objective The aim of this article is to summarise the evidence examining the role of exercise in cancer care. Discussion Exercise is a safe and effective adjunct therapy in cancer care. Patients with cancer who regularly engage in moderate-intensity exercise are more likely to have: fewer and less severe treatment-related side effects; a lower relative risk of developing other chronic diseases; and, in some cases, a lower relative risk of cancer recurrence and mortality. Available evidence highlights the benefits of general practitioners (GPs) discussing and recommending exercise to their patients with cancer. To optimise the therapeutic effect of exercise, GPs may consider referring patients with cancer to an exercise physiologist or physiotherapist who has experience in cancer care

eHealth tools for childhood cancer survivorship care: A qualitative analysis of survivors', parents', and general practitioners' views

Objective: We assessed the acceptability of, and perceived benefits/barriers to, using Electronic health (eHealth) technology for childhood cancer survivorship care. Methods: We interviewed survivors, their parents, and their nominated GP. We described a hypothetical eHealth tool to manage survivorship care and asked their likely use of, and perceived benefits/concerns for, the use of the tool. Results: 31 survivors (mean age = 27.0), 29 parents (survivors' mean age = 12.6), and 51 GPs (mean years practising = 28.2) participated. Most survivors/parents (85%) and GPs (75%) indicated that they would be willing to use an eHealth tool. Survivors/parents reported that an eHealth tool would increase their confidence in their ability, and their GP's ability, to manage their survivorship care. GPs agreed that an eHealth tool would provide easier access to survivors' medical information and increase their capacity to provide support during survivorship. Some GPs (7%) and survivors (43%) reported being hesitant to use eHealth tools due to privacy/security concerns. Conclusion: Overall, eHealth tools appear acceptable and may help to improve the management of late effects for childhood cancer survivors and assist their GPs to coordinate their care. Innovation: Concerns raised by key stakeholders should be addressed in the design of eHealth technologies to optimise their uptake and effectiveness.</p