Regulations on safe ultrasound exposure limits are based on a very limited number of studies, which have only considered audiometric threshold shifts as indicators of hearing deficits. The purpose of the current study was to assess the effects of exposure to high-intensity ultrasound on a range of measures of hearing function, which included audiometric thresholds, as well as subclinical measures of hearing deficits: speech-in-noise understanding, supra-threshold auditory brainstem response wave I amplitude and latency, and frequency following response levels to amplitude modulated (AM) tones. Changes in these measures were assessed before and after exposure of the left ear to high-intensity ultrasound in a group of nine young listeners. These changes were compared to those observed in a control group of nine young listeners. Exposure consisted in the presentation of a 40-kHz AM tone at levels of 105, 110, 115, and 120 dB SPL for 10 minutes at each level, plus an exposure to a 40-kHz unmodulated tone during an ultrasound detection task, for a total duration of 50 seconds. None of the measures of hearing function was found to change significantly more for the left compared to the right ear, for participants of the exposure group compared to control participants. Electroencephalographic recordings obtained during exposure to the AM tone did not show significant phase-locked activity at the modulation frequency or at low-frequency subharmonics of the ultrasound tone. One out of nine participants was able to perform the ultrasound detection task above chance level, although due to limitations of the experimental setup the mechanism by which she could detect the presentation of the tone remains unclear.

IntroductionThe automated breast volume scanner (ABVS) is the fi rst of its kind and utilises a large, 17 cm × 15 cm high-frequency ultrasound probe which sweeps across the whole breast generating images that can be reformatted into multiple planes and a 3D volume. ABVS will change breast ultrasound practice by: introducing operator standardisation, reproducibility and repeatability of measurement and interpretation; changing who acquires the volume set and how breast ultrasounds are reported; and allowing accurate comparison of previous and current examinations for screening and assessing treatment change. Methods Patients presented to the symptomatic clinic for conventional 2D ultrasound assessment with a variety of conditions. An additional ABVS was performed. Results Cases were classifi ed into: benign -for example, cysts, fi broadenomas, diabetic mastopathy; and malignant. Conclusion We present a review of our initial experience and highlight its advantages over conventional ultrasound, which include: improved mapping of lesions enabling more accurate future assessment and follow-up, and improved assessment of distortion over conventional 2D ultrasound. Further research is required to explore other potential benefi ts. Introduction A study of symptomatic breast units geographically spread over Ireland collected image quality, compression and radiation dose data from 18 mammography units; so how do these optimisation parameters compare nationally and internationally? The mean glandular dose (MGD) diagnostic reference level was proposed for the all-digital breast screening service [1] but not for the symptomatic breast service. Methods The quantitative and qualitative data were analysed using SPSS. Recommendations of MGD diagnostic reference levels were made at various levels for fi lm-screen mammography (FSM) and full-fi eld digital mammography (FFDM) units to match those levels published in worldwide. O2 Symptomatic breast services inResults MGDs received by symptomatic breast patients within Ireland are higher than those received in the all-digital Irish Breast Screening service, although the diff erences for FFDM are not substantial; 55 to 65 mm breast: 1.75 mGy (screening) versus 2.4 mGy (symptomatic) at the 95th percentile. The four-view routine mammography MGDs obtained in symptomatic breast units in Ireland are, however, substantially diff erent from other screening units with mixed FSM/FFDM modalities: 4.5 mGy (UK); 4.98 mGy (USA) versus 5.96 mGy (FFDM, symptomatic) and 9.63 mGy (FSM, symptomatic). Various reasons are proposed for the diff erences. Conclusion MGD diagnostic reference levels achieved in the screening service may be lower due to the exacting requirements for radiographer training, nonsurgical alteration of patient breasts and equipment quality assurance levels. Greater training of radiographers performing mammography in the symptomatic breast services is required to standardise mammographic projections with regard to MGDs delivered. Reference O3Correlations between shear wave elastog...

Breast ultrasound (BUS) imaging is an imaging modality used for the detection and diagnosis of breast lesions and it has become a crucial modality nowadays specially for providing a complementary view when other modalities (i.e. mammography) are not conclusive. However, lesion detection in ultrasound images is still a challenging problem due to the presence of artifacts such as low contrast, speckle, inhomogeneities and shadowing. In order to deal with these problems and improve diagnosis accuracy, radiologists tend to complement ultrasound imaging with elastography data. Following the prominent relevance of elastography in clinical environments, it is reasonable to assume that lesion segmentation methods could also benefit from this complementary information. This paper proposes a novel breast ultrasound lesion segmentation framework for B-mode images including elastography information. A distortion field is estimated to restore the ideal image while simultaneously identifying regions of similar intensity inhomogeneity using a Markov Random Field (MRF) and a maximum a posteriori (MAP) formulation. Bivariate Gaussian distributions are used to model both B-mode and elastography information. This paper compares the fused B-mode and elastography framework with B-mode or elastography alone using different cases, including extreme cases, where B-mode shows a well defined lesion and where elastography provides more meaningful information, showing a significant improvement when B-mode images are not conclusive which is the often the case in non cystic lesions. Results show that combining both B-mode and elastography information in an unique framework makes the algorithm more robust and image quality independent.

Ultrasound (US) elastography is an image processing technique used to evaluate the mechanical properties of soft biological tissue, making it a promising non invasive diagnostic and screening tool. The accessibility to the RF data of 2D transducers has led to a focus on 1D and 2D techniques. However, the inherent 3D movement of tissue under loading forces during image acquisition inevitably produces out-ofplane motion; a significant source of noise in 2D elastograms. This paper presents a direct 3D axial strain estimation algorithm which exploits fundamental image processing techniques to form a method which is both robust and computationally efficient. Displacement estimation is first carried out using integral images/volumes that allow for a quick and near exhaustive motion tracking scheme with maximum window overlap. Subsequently, paired regions are subjected to a fast spectral shift measurement for axial strain estimation that utilizes Fourier cross correlation to reduce the computational burden previously associated with spectral methods. The resulting system was found to be more robust to displacement estimation noise than standard gradient based techniques while remaining significantly faster than adaptive local registration methods. The 3D method was tested on simulated and real US data obtained from freehand scanning. I INTRODUCTIONUltrasound elastography is an emerging technique that aims to measure mechanical properties of soft biological tissues. A stiffening of tissue can be brought on by various pathological processes, not least of which cancer. Consequently, a strain field map can provide a high contrast visualization of tumours and other lesions. Likewise, a 3D view offers a better visualization for clinicians to assess the size and shape of a lesion.The challenge faced in any elastography method first begins with tracking the movement of tissue between pre and post compression frames. Of the various techniques that have been developed, precision in the displacement estimate is essential and thus there has been a focus on producing more reliable or faster ways to generate a displacement field [4,5,10]. The two major time domain methods for calculating strain involve gradient and registration based approaches. Gradient based approaches derive strain by taking the gradient of the displacement field. They are generally fast (real time 2D imaging based on these approaches is available on several commercial systems) but suffer from noise introduced by the gradient operator. Registration methods attempt to derive strain by registering pre and post compression frames using non-rigid transformations typically via an iterative/adaptive process [1,3,8]. They are more robust but have a significantly higher computational cost, thus limiting their use for practical clinical applications. Consequently, the focus of this paper has been to create an algorithm that addresses this apparent tradeoff between speed and robustness. The proposed method was designed effectively as a faster frequency domain adaptation to ...

The extensive use of touchscreens for all manner of human-computer interactions has made them plausible instruments of touch-mediated disease transmission. To that end, we employ stochastic simulations to model human-fomite interaction with a distinct focus on touchscreen interfaces. The timings and frequency of interactions from within a closed population of infectious and susceptible individuals was modelled using a basic queuing network. A pseudo reproductive number (R) was used to compare outcomes under various parameter conditions. We also expanded the simulation to a specific real-world scenario; namely airport self check-in and baggage drop. Results revealed that the required rate of cleaning/disinfecting of screens to effectively mitigate R can be inordinately high. This suggests that revised or alternative methods should be considered.