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Digital Breast Tomosynthesis has several advantages over traditional 2D mammography. However, the cost-effectiveness to implement DBT modality into breast screening programmes is still under investigation. The DBT modality has been integrated into a regional breast screening program in Italy for several years. The purpose of this study is to examine the experienced Italian DBT readers’ visual search behaviour and summarise their visual inspection patterns. Seven experienced radiologists took part in the study, reading a set of DBT cases with a mixture of both normal and abnormal cases whilst their eye movements data were recorded. They read the cases through a fixed procedure starting with a 2D overview and then went through the DBT view of each side of the breasts. It was found that the experienced readers tended to perform a global-focal scan over the 2D view to detect the abnormality and then ‘drilled’ through the DBT slices, interpreting the details of the feature. The reading speed was also investigated to see if there was any difference in length of time when expert radiologists examine both normal and abnormal cases. The results showed that there was no significant difference in time between normal and abnormal cases. The eye movement patterns revealed that experienced DBT readers covered more areas on the 2D view and fixated longer and with more dwells inside the AOI in the 3D view. Based on these findings it is hoped that by understanding the visual search patterns of the experienced DBT radiologists, it could potentially help DBT trainees to develop more efficient interpretation approaches.

Is there a difference in reading time when normal and abnormal DBT cases are examined by DBT experienced radiologists?

The UK’s Breast Screening Programme is 27 years old and many experienced breast radiologists are now retiring, coupled with an influx of new screening personnel. It is important to the ongoing Programme that new mammography readers are quickly up to the skill level of experienced readers. This raises the question of how quickly the necessary cancer detection skills are learnt. All breast screening radiologists in the UK read educational training sets of challenging FFDM images (the PERFORMS® scheme) yearly to maintain and improve their performance in real life screening. Data were examined from the PERFORMS® annual scheme for 54 new screeners, 55 screeners who have been screening for one year and also for more experienced screeners (597 screeners). Not surprisingly, significant differences in cancer detection rate were found between new readers and both of the other groups. Additionally, the performance of 48 new readers who have now been screening for about a year and have taken part twice in the PERFORMS® scheme were further examined where again a significant difference in cancer detection was found. These data imply that cancer detection skills are learnt quickly in the first year of screening. Information was also examined concerning the volume of cases participants read and other factors.

Visual search techniques and FROC analysis have been widely used in radiology to understand medical image perceptual behaviour and diagnostic performance. The potential of exploiting the advantages of both methodologies is of great interest to medical researchers. In this study, eye tracking data of eight dental practitioners was investigated. The visual search measures and their analyses are considered here. Each participant interpreted 20 dental radiographs which were chosen by an expert dental radiologist. Various eye movement measurements were obtained based on image area of interest (AOI) information. FROC analysis was then carried out by using these eye movement measurements as a direct input source. The performance of FROC methods using different input parameters was tested. The results showed that there were significant differences in FROC measures, based on eye movement data, between groups with different experience levels. Namely, the area under the curve (AUC) score evidenced higher values for experienced group for the measurements of fixation and dwell time. Also, positive correlations were found for AUC scores between the eye movement data conducted FROC and rating based FROC. FROC analysis using eye movement measurements as input variables can act as a potential performance indicator to deliver assessment in medical imaging interpretation and assess training procedures. Visual search data analyses lead to new ways of combining eye movement data and FROC methods to provide an alternative dimension to assess performance and visual search behaviour in the area of medical imaging perceptual tasks.

Traditional modeling system methods are mainly on system mechanism and structures. For many applications interaction between user and system is important. How to model and analyze user behaviors is becoming more and more important and it is applied to solve problems of user interest, information service recommendation, network security and so on. This paper introduces an algorithm to extract and model user interaction behaviors from system logs and represent them in the form of user interaction behaviors net. By combining user interaction behaviors net with user log datasets stored in system log, it is possible to describe user behaviors in a much more comprehensive and effective manner. Results show that the algorithm can successfully model user behaviors and supply a new description basis for user behavior feature extraction and identification.

This paper describes the implementation of serial communication between the PLC and the host-computer in the control system of home environment, gives a detailed introduction to the communication protocols, parameters setting and also gives part of the serial-communication program based on visual basic 6.0. It shows that this control system meets the requirements as expected.

In this paper a new approach is proposed to track the perceptual behaviour of radiologists when they examine mammographic images displayed on large dual clinical monitors. Zooming and panning are inevitably performed by the radiologist to examine such large images by using the DICOM viewing software. Such image manipulating movements on the target displays makes eye tracking techniques difficult to perform and also the size of the dual clinical monitors makes existing eye tracking techniques generally inadequate. Hence a method using the Smart Eye Pro eye tracker and optical character recognition techniques was designed to relate the recorded radiologists’ eye gaze behaviour on the monitors to the actual zoomed and panned medical image areas. This then allows clinical studies involving radiologists interacting with these mammographic images to be successfully carried out.

Aim To develop a system to assess the image interpretation performance of radiologists in identifying signs of malignancy on chest radiographs. Materials and methods A test set of 30 chest radiographs was chosen by an experienced radiologist consisting of 11 normal and 19 abnormal cases. The malignant cases all had biopsy-proven pathology; the normal and benign cases all had at least 2 years of imaging follow-up. Fourteen radiologists with a range of experiences were recruited. Participants individually read the test set displayed on a standard reporting workstation, with their findings entered directly into a laptop running specially designed reporting software. For each case, relevant clinical information was given and the reader was asked to mark any perceived abnormality and rate their level of suspicion on a five-point scale (normal, benign, indeterminate, suspicious, or malignant). On completion, participants were given instant feedback with performance parameters including sensitivity and specificity automatically calculated. An opportunity was then given to review the cases together with an expert opinion and pathology. The time each participant took to complete the test was recorded. Results Six consultant radiologists who took part showed significantly better performance as determined by receiver operating characteristic (ROC) analysis compared to eight specialist registrars (area under the ROC curve [AUC]=0.9297 and 0.7648 respectively, p =0.003). There was a significant correlation with years of experience in the interpretation of chest radiographs and performance on the test set ( r =0.573, p =0.032). Consultant radiologists completed the test significantly more quickly that the specialist registrars: mean time 19.65 minutes compared to 26.51 minutes ( p =0.033). Conclusion It is possible to use a test set to measure individual differences in the interpretation of chest radiographs. This has the potential to be a useful tool in performance testing.

To examine the utility of employing breast screening test sets internationally the data of 1,009 radiologists from the USA, UK and other European countries were examined as they inspected 20 carefully selected difficult recent screening cases. Some 720 UK radiologists, 247 American and 42 European radiologists took part. Whilst similar sensitivity scores between the three groups were found, the main difference was the lower specificity of the American radiologists reflecting their different recall clinical practice. It is argued that using test sets internationally provides participants with useful comparative performance information whilst also providing data on how the same cases are interpreted by radiologists from different countries.

This paper describes the implementation of serial communication between the PLC and the host- computer in the control system of Spatial Carport, gives a detailed introduction to the communication protocols, parameters setting and also gives part of the serial-communication program based on visual basic 6.0. It shows that this control system meets the requirements as expected.

A facile, low cost, and relatively environmental friendly method was presented for the fabrication of superhydrophobic surface on carbon steel substrate. The superhydrophobic surface was obtained by zinc electrodeposition and chemical modification with ethanolic stearic acid. The wettability of the superhydrophobic surface was measured by a water contact angle (WCA) with a highest value of 155.7°. The morphology of the fabricated film was characterized by scanning electron microscopy (SEM). The chemical composition of the fabricated surface was analysed by energy dispersive spectrometer (EDS) and fourier transform infrared spectroscopy (FTIR), respectively. The corrosion resistance of the carbon steel substrate was measured by potentiodynamic polarization test in 3.5 wt% NaCl solution. The electrochemical measurements show excellent corrosion resistance, which may have promising applications in anticorrosion of carbon steel.

Laparoscopic surgery provides a very complex example of medical image interpretation. The task entails: visually examining a display that portrays the laparoscopic procedure from a varying viewpoint; eye-hand coordination; complex 3D interpretation of the 2D display imagery; efficient and safe usage of appropriate surgical tools, as well as other factors. Training in laparoscopic surgery typically entails practice using surgical simulators. Another approach is to use cadavers. Viewing previously recorded laparoscopic operations is also a viable additional approach and to examine this a study was undertaken to determine what differences exist between where surgeons look during actual operations and where they look when simply viewing the same pre-recorded operations. It was hypothesised that there would be differences related to the different experimental conditions; however the relative nature of such differences was unknown. The visual search behaviour of two experienced surgeons was recorded as they performed three types of laparoscopic operations on a cadaver. The operations were also digitally recorded. Subsequently they viewed the recording of their operations, again whilst their eye movements were monitored. Differences were found in various eye movement parameters when the two surgeons performed the operations and where they looked when they simply watched the recordings of the operations. It is argued that this reflects the different perceptual motor skills pertinent to the different situations. The relevance of this for surgical training is explored.

Laparoscopic surgery is a difficult perceptual-motor task and effective and efficient training in the technique is important. Viewing previously recorded laparoscopic operations is a possible available training technique for surgeons to increase their knowledge of such minimal access surgery (MAS). It is not well known whether this is a useful technique, how effective it is or what effect it has on the surgeon watching the recorded video. As part of an on-going series of studies into laparoscopic surgery, an experiment was conducted to examine whether surgical skill level has an effect on the visual search behaviour of individuals of different surgical experience when they examine such imagery. Medically naive observers, medical students, junior surgeons and experienced surgeons viewed a laparoscopic recording of a recent operation. Initial examination of the recorded eye movement data indicated commonalities between all observers, largely irrespective of surgical experience. This, it is argued, is due to visual search in this situation largely being driven by the dynamic nature of the images. The data were then examined in terms of surgical steps and also in terms of interventions when differences were found related to surgical experience. Consequently, it is argued that monitoring the eye movements of trainee surgeons whilst they watch pre-recorded operations is a potential useful adjunct to existing training regimes.