Several groups are studying acoustic radiation force and its ability to image the mechanical properties of tissue. Acoustic radiation force impulse (ARFI) imaging is one modality using standard diagnostic ultrasound scanners to generate localized, impulsive, acoustic radiation forces in tissue. The dynamic response of tissue is measured via conventional ultrasonic speckle-tracking methods and provides information about the mechanical properties of tissue. A finite-element method (FEM) model has been developed that simulates the dynamic response of tissues, with and without spherical inclusions, to an impulsive acoustic radiation force excitation from a linear array transducer. These FEM models were validated with calibrated phantoms. Shear wave speed, and therefore elasticity, dictates tissue relaxation following ARFI excitation, but Poisson's ratio and density do not significantly alter tissue relaxation rates. Increased acoustic attenuation in tissue increases the relative amount of tissue displacement in the near field compared with the focal depth, but relaxation rates are not altered. Applications of this model include improving image quality, and distilling material and structural information from tissue's dynamic response to ARFI excitation. Future work on these models includes incorporation of viscous material properties and modeling the ultrasonic tracking of displaced scatterers.

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Levels of psychiatric morbidity, burnout and work dissatisfaction are worryingly high in colorectal and vascular surgeons and are likely to impact adversely on patient satisfaction and service quality. The number of surgeons intending to retire early is also a cause for concern both in terms of the overall number of trained surgeons in the NHS and in the balance between senior and junior surgeons. Apart from DP, these indicators of stress, however, were unrelated to cancer workload.

Objectives To investigate factors which influenced UK-trained doctors to emigrate to New Zealand and factors which might encourage them to return. Design Cross-sectional postal and Internet questionnaire survey. Setting Participants in New Zealand; investigators in UK. Participants UK-trained doctors from 10 graduation-year cohorts who were registered with the New Zealand Medical Council in 2009. Main outcome measures Reasons for emigration; job satisfaction; satisfaction with leisure time; intentions to stay in New Zealand; changes to the UK NHS which might increase the likelihood of return. Results Of 38,821 UK-trained doctors in the cohorts, 535 (1.4%) were registered to practise in New Zealand. We traced 419, of whom 282 (67%) replied to our questionnaire. Only 30% had originally intended to emigrate permanently, but 89% now intended to stay. Sixty-nine percent had moved to take up a medical job. Seventy percent gave additional reasons for relocating to New Zealand including better lifestyle, to be with family, travel/working holiday, or disillusionment with the NHS. Respondents' mean job satisfaction score was 8.1 (95% CI 7.9–8.2) on a scale from 1 (lowest satisfaction) to 10 (highest), compared with 7.1 (7.1–7.2) for contemporaries in the UK NHS. Scored similarly, mean satisfaction with the time available for leisure was 7.8 (7.6–8.0) for the doctors in New Zealand, compared with 5.7 (5.6–5.7) for the NHS doctors. Although few respondents wanted to return to the UK, some stated that the likelihood of doctors' returning would be increased by changes to NHS working conditions and by administrative changes to ease the process. Conclusions Emigrant doctors in New Zealand had higher job satisfaction than their UK-based contemporaries, and few wanted to return. The predominant reason for staying in New Zealand was a preference for the lifestyle there.

We found high levels of psychiatric morbidity and burnout in this national cohort of surgeons and nurses working in the NHS. However, psychiatric morbidity and burnout were unrelated to cancer workload. Nurses have lower burnout levels than surgeons and this may be related to their different working practices, responsibilities and management structure.