Trust makers, breakers and brokers: building trust in the Australian food system

Background

The importance of consumer trust in the food supply has previously been identified, and dimensions of consumer trust in food—who they trust and the type of trust that they exhibit—has been explored. However, there is a lack of research about the mechanisms through which consumer trust in the food supply is developed, maintained, broken and repaired. This study seeks to address this gap by exploring if, and how, consumer trust in the food supply is considered by the media, food industry and governments when responding to food scares. The aim of the research is to develop models of trust building that can be implemented following food scares.

Methods

Semi-structured interviews will be undertaken with media, public relations officials and policy makers in Australia, New Zealand and the United Kingdom. Participants will be recruited through purposive sampling and will be asked to discuss a hypothetical case study outlining a food incident, and any experiences of specific food scares. Models of trust development, maintenance and repair will be developed from interview data. Comment on these models will be sought from experts in food-related organizations through a Delphi study, where participants will be asked to consider the usefulness of the models. Participants’ comments will be used to revise the models until consensus is reached on the suitability and usability of the models.

Discussion

This study will contribute to the literature about systems-based trust, and explore trust as a social and regulatory process. The protocol and results will be of interest and use to the food industry, food regulators, consumer advocate groups, media seeking to report food-related issues and policy makers concerned with public health and consumer health and well-being. This research represents an important contribution to the translation of the theoretical conceptualizations of trust into practical use in the context of food.

An inverse problem approach to recovery of in vivo nanoparticle concentrations from thermal image monitoring of MR-guided laser induced thermal therapy

Quantification of local variations in the optical properties of tumor tissue introduced by the presence of gold-silica nanoparticles (NP) presents significant opportunities in monitoring and control of NP-mediated laser induced thermal therapy (LITT) procedures. Finite element methods of inverse parameter recovery constrained by a Pennes bioheat transfer model were applied to estimate the optical parameters. Magnetic resonance temperature imaging (MRTI) acquired during a NP-mediated LITT of a canine transmissible venereal tumor in brain was used in the presented statistical inverse problem formulation. The maximum likelihood (ML) value of the optical parameters illustrated a marked change in the periphery of the tumor corresponding with the expected location of NP and area of selective heating observed on MRTI. Parameter recovery information became increasingly difficult to infer in distal regions of tissue where photon fluence had been significantly attenuated. Finite element temperature predictions using the ML parameter values obtained from the solution of the inverse problem are able to reproduce the NP selective heating within 5 °C of measured MRTI estimations along selected temperature profiles. Results indicate the ML solution found is able to sufficiently reproduce the selectivity of the NP mediated laser induced heating and therefore the ML solution is likely to return useful optical parameters within the region of significant laser fluence.

Computational modeling and real-time control of patient-specific laser treatment of cancer

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Development of a guarded liquid ionization chamber for clinical dosimetry

Liquid ionization chambers are considered superior to air-filled chambers in terms of size, energy dependence and perturbation effects. We constructed and tested a liquid ionization chamber for clinical dosimetry, the GLIC-03, with a sensitive volume of approximately 2 mm3. We also examined two methods to correct for general ion recombination in pulsed photon beams: that of Johansson et al, which modifies Boag's theory for recombination in gases, and an empirical method relating recombination to dose per pulse. The second method can be used even in cases where the first method is not applicable. The response of the GLIC-03 showed a stable, linear and reproducible decrease of 1% over 10 h. The liquid-filled GLIC-03 had a 1.1 +/- 0.4% energy dependence while that of the air-filled GLIC-03 was 2.1 +/- 0.3% between the 6 and 18 MV beams from a Clinac 21EX. The two methods for recombination correction agreed within 0.2% for measurements at 18 MV, 700 V, 100 MU min(-1). Measurements with the GLIC-03 in Solid Water in the build-up region of an 18 MV beam agreed with extrapolation chamber measurements within 1.4%, indicating that the GLIC-03 causes minimal perturbation.

Dynamic Data-Driven Finite Element Models for Laser Treatment of Cancer

Elevating the temperature of cancerous cells is known to increase their susceptibility to subsequent radiation or chemotherapy treatments, and in the case in which a tumor exists as a well-defined region, higher intensity heat sources may be used to ablate the tissue. These facts are the basis for hyperthermia based cancer treatments. Of the many available modalities for delivering the heat source, the application of a laser heat source under the guidance of real-time treatment data has the potential to provide unprecedented control over the outcome of the treatment process [7, 18]. The goals of this work are to provide a precise mathematical framework for the real-time finite element solution of the problems of calibration, optimal heat source control, and goal-oriented error estimation applied to the equations of bioheat transfer and demonstrate that current finite element technology, parallel computer architecture, data transfer infrastructure, and thermal imaging modalities are capable of inducing a precise computer controlled temperature field within the biological domain.