Alastair Gale - Academia.edu (original) (raw)
Papers by Alastair Gale
Springer eBooks, 2017
The conventional 'keyboard and workstation' approach allows complex medical image presentation an... more The conventional 'keyboard and workstation' approach allows complex medical image presentation and manipulation during mammographic interpretation. Nevertheless, providing rich interaction and feedback in real time for navigational training or computer assisted detection of disease remains a challenge. Through computer vision and state of the art AR (Augmented Reality) technique, this study proposes an 'AR mammographic workstation' approach which could support workstationindependent rich interaction and real-time feedback. This flexible AR approach explores the feasibility of facilitating various mammographic training scenes via AR as well as its limitations.
A dedicated workstation and its corresponding viewing software are essential requirements in brea... more A dedicated workstation and its corresponding viewing software are essential requirements in breast screener training. A major challenge of developing further generic screener training technology (in particular, for mammographic interpretation training) is that high-resolution radiological images are required to be displayed on dedicated workstations whilst actual reporting of the images is generally completed on individual standard workstations. Due to commercial reasons, dedicated clinical workstations manufactured by leading international vendors tend not to have critical technical aspects divulged which would facilitate further integration of third party generic screener training technology. With standard workstations, it is noticeable that the conventional screener training depends highly on manual transcription so that traditional training methods can potentially be deficient in terms of real-time feedback and interaction. Augmented reality (AR) provides the ability to cooperate with both real and virtual environments, and therefore can supplement conventional training with virtual registered objects and actions. As a result, realistic screener training can cooperate with rich feedback and interaction in real time. Previous work 1 has shown that it is feasible to employ an AR approach to deliver workstation-independent radiological screening training by superimposing appropriate feedback coupled with the use of interaction interfaces. The previous study addressed presence issues and provided an AR recognisable stylus which allowed for drawing interaction. As a follow-up, this study extends the AR method and investigates realistic effects and the impacts of environmental illumination, application performance and transcription. A robust stylus calibration method is introduced to address environmental changes over time. Moreover, this work introduces a completed AR workflow which allows real time recording, computer analysable training data and further recoverable transcription during post-training. A quantitative evaluation results show an accuracy of more than 80% of user-drawn points being located within a pixel distance of 5.
International Journal of Information Technology and Computer Science, Aug 8, 2018
Under the Digital Image and Communication in Medicine (DICOM) standard, the Advanced Encryption S... more Under the Digital Image and Communication in Medicine (DICOM) standard, the Advanced Encryption Standard (AES) is used to encrypt medical image pixel data. This highly sensitive data needs to be transmitted securely over networks to prevent data modification. Therefore, there is ongoing research into how well encryption algorithms perform on medical images and whether they can be improved. In this paper, we have developed an algorithm using a chaotic map combined with AES and tested it against AES in its standard form. This comparison allowed us to analyse how the chaotic map affected the encryption quality. The developed algorithm, CAT-AES, iterates through Arnold's cat map before encryption a certain number of times whereas, the standard AES encryption does not. Both algorithms were tested on two sets of 16-bit DICOM images: 20 brain MRI and 26 breast cancer MRI scans, using correlation coefficient and histogram uniformity for evaluation. The results showed improvements in the encryption quality. When encrypting the images with CAT-AES, the histograms were more uniform, and the absolute correlation coefficient was closer to zero for the majority of images tested on.
Proceedings of SPIE, Mar 10, 2017
Appropriate feedback plays an important role in optimising mammographic interpretation training w... more Appropriate feedback plays an important role in optimising mammographic interpretation training whilst also ensuring good interpretation performance. The traditional keyboard, mouse and workstation technical approach has a critical limitation in providing supplementary image-related information and providing complex feedback in real time. Augmented Reality (AR) provides a possible superior approach in this situation, as feedback can be provided directly overlaying the displayed mammographic images so making a generic approach which can also be vendor neutral. In this study, radiological feedback was dynamically remapped virtually into the real world, using perspective transformation, in order to provide a richer user experience in mammographic interpretation training. This is an initial attempt of an AR approach to dynamically superimpose pre-defined feedback information of a DICOM image on top of a radiologist's view, whilst the radiologist is examining images on a clinical workstation. The study demonstrates the feasibility of the approach, although there are limitations on interactive operations which are due to the hardware used. The results of this fully functional approach provide appropriate feedback/image correspondence in a simulated mammographic interpretation environment. Thus, it is argued that employing AR is a feasible way to provide rich feedback in the delivery of mammographic interpretation training.
Proceedings of SPIE, Mar 10, 2017
The British journal of radiology, Jan 11, 2015
To compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT)... more To compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT) for assessment of soft tissue mammographic abnormalities. Women recalled for further assessment of soft tissue abnormalities were recruited and received standard supplementary views (typically spot compression views) and two view GE DBT. The added value of DBT in the assessment process was determined by analysing data collected prospectively by radiologists working up the cases. Following anonymisation of cases, there was also a retrospective multireader review. The readers first read bilateral standard two view digital mammography (DM) together with the supplementary mammographic views and gave a combined score for suspicion of malignancy on a five point scale. The same readers then read bilateral standard two view DM together with two view DBT. Pathology data was obtained. Differences were assessed using ROC analysis. The study population was 342 lesions in 322 patients. Final diagnos...
Clinical Radiology, Mar 1, 2017
Diagnostic and Prognostic Research, 2017
Diagnostic and Prognostic Research, 2017
Background: The Test-Treatment Pathway has been proposed as a method to link test accuracy to dow... more Background: The Test-Treatment Pathway has been proposed as a method to link test accuracy to downstream outcomes. By describing the clinical actions before and after testing, it illustrates how a test is positioned in the pathway, relative to other tests and diagnostics, and how the introduction of a new test may change the current diagnostics pathway. However, there is limited practical guidance on how to model such Test-Treatment Pathways. Methods: We selected the Patient-Index test-Comparator-Outcome (PICO) format, as also used elsewhere in evidence-based medicine, as a starting point for building the Test-Treatment Pathways. From there we developed a structured set of triggering questions. We defined these questions based on several brainstorm sessions and iteratively made changes to this basic structure after three rounds of user testing. During the user testing meetings, a pathway was drawn for each specific application. All sessions were recorded both on audio and video. Results: We present examples of four different Test-Treatment Pathways. User testing revealed that all users found the process of drawing the pathway very useful, but they also felt that this is just the first step in a process. The steps from pathway derivation to key questions remains difficult. Challenges in deriving the pathway were that interviewee(s) may wander off topic and that some problems cannot be captured in only one pathway. Further training was deemed desirable. Users would also like to see an electronic tool. They had no clear preference when offered a choice between a more open interviewing approach versus a more closed checklist approach. Discussion: Modelling Test-Treatment pathways is a useful step in synthesizing the evidence about medical tests and developing recommendations about them, but further technical development and training are needed to facilitate their use in evidence-based medicine. O2 Using machine learning and crowdsourcing for the identification of diagnostic test accuracy
Breast Cancer Research, 2015
Introduction: The aim was to compare the accuracy of standard supplementary views and GE digital ... more Introduction: The aim was to compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT) for assessment of soft tissue mammographic abnormalities. Methods: Women recalled for further assessment of soft tissue abnormalities were recruited and received standard supplementary views (typically spot compression views) and two-view GE DBT. The added value of DBT in the assessment process was determined by analysing data collected prospectively by unblinded radiologists working up the cases. Following anonymisation of cases, there was also a retrospective multireader review. The readers first read bilateral standard two-view digital mammography (DM) together with the supplementary mammographic views and gave a combined score for suspicion of malignancy on a fivepoint scale. The same readers then read bilateral standard two-view DM together with two-view DBT. Pathology data were obtained. Differences were assessed using ROC analysis. Results: The study population was 342 lesions in 322 patients. Final diagnosis was malignant in 113 cases (33%) and benign/normal in 229 cases (67%). In the prospective analysis, the performance of two-view DM plus DBT was at least equivalent to the performance of two-view DM and standard mammographic supplementary views-area under the curve (AUC) was 0.946 and 0.922 respectively, which did not reach statistical significance. Similar results were obtained for the retrospective review-AUC was 0.900 (DBT) and 0.873 (supplementary views), which did not reach statistical significance. Conclusion: The accuracy of GE DBT in the assessment of screendetected soft tissue abnormalities is equivalent to the use of standard supplementary mammographic views.
Behavior Research Methods Instruments & Computers, Nov 1, 2002
Background to the Project This paper describes the design and construction of an eye-tracking exh... more Background to the Project This paper describes the design and construction of an eye-tracking exhibit and experiment that was part of a public exhibitionentitled "Telling Time" at the National Gallery, London, from October 18, 2000 to January 14, 2001. Designed and built by the Applied Vision Research Unit of the University of Derby, the exhibit functioned as a controlled eye movement experiment on a large number of participants, providing a wealth of data on how individuals look at images in general and at paintings in particular. Its aim also was to illustrate to members of the public that viewing a picture is not an instantaneous process but that our understanding of the image develops as we stand before it. Although there have been eye-tracking exhibits in museums and science centers around the world (see, e.g., Buquet, Charlier, & Paris, 1988; Glenstrup & Engell-Nielsen,1995; and see Appendix A), these have focused on the eye tracker as a public science exhibit, rather than being used to gather scientific data. The Demands of the Exhibit The exhibit as experiment. The exhibit was designed to function as a scientifically rigorous experiment that would record the eye movements of large numbers of individuals as they viewed images of paintings. Traditional eye movement experiments use relatively small numbers of participants. With a large number of participants, the data could be generalized widely, with each stimulus being observed by more than 100 participants. The experiment as exhibit. To encourage participation, the exhibit was as interactive as possible. A large "public" display alongside the exhibit was controlled by the same computer that was running both the experiment and the eye-tracking system and displayed the live eye movements of the current participant. Each participant's eye movements were also replayed while the next participant was undergoing the necessary calibration process. When no current data were available, the public display replayed prerecorded traces or showed more complex representations of eye movement data. Participants. The participants were self-selected visitors to the exhibition.Data from 1995/1996 show approximately equal numbers of men and women visitors to the Gallery, peakingin the 15-to 34-year-old group. Recordingeye movements is more difficult in older participants, so a preponderance of the young among visitors was favorable. The project was approved by the University Ethics Committee, and the self-selecting participants were informed of the purpose of the experiment through carefully worded static displays accompanying the exhibit. Requirements of the design. As exhibitvisitors, the participants were typically "naive," with no prior knowledge of eye movements or of the purpose of the experiment. Consequently, in use, the exhibit needed to be intuitive and user-friendly, with minimal per-participant time, while maximizing the experimental and exhibition properties. The main challenge of the exhibit was to record eye movements automatically from a wide range of people without being intrusive, intimidating, or uncomfortable. Recording eye movements typically requires a skilled human operator, but the autonomous system had to operate unattended and with minimal operator interventionfor the 3-month duration of the exhibition.
Medical Imaging 2021: Image Perception, Observer Performance, and Technology Assessment, 2021
The UK national screening program for breast cancer currently uses Full Field Digital Mammography... more The UK national screening program for breast cancer currently uses Full Field Digital Mammography (FFDM). Various studies have shown that DBT has a higher sensitivity and specificity in identifying early breast cancer apart from benign pathologies, even in very dense breasts. This potentially makes DBT a better screening modality to detect early breast cancer, as well as minimize false positive recall rates. However, DBT has multiple image slices and thereby makes reading cases inherently a longer and potentially more visually fatiguing task. Our previous studies (Dong et al, 2017 and 2018) have demonstrated the impact of institutional training on reading techniques in DBT. The reading technique itself appears to have an effect on total reading time. In other follow-on studies we have employed eye tracking which gives rise to complex data sets, including parameters such as eyelid opening and pupil diameter measures, which can then be employed to gauge blinks and fatigue onset. Findings from this work have guided changes in our blink identification techniques and we have now developed semi-automated programmed processes which can analyze the large data set and provide a more accurate assessment of fatigue and vigilance parameters through blink detection. Here, we have considered ‘eyelid opening’ parameters of both the left and the right eye separately. Having such a separated approach allowed us to tease out particular aspects of blinking. Similar to Schleicher et al (2008), we found there to be ultra-short blinks (30-50 milli seconds), short blinks (51- 100 msecs), long blinks (101-500 msecs) and also microsleeps (>500 msecs). We argue that the changes observed in the frequencies of these blinks can be used as a measure of vigilance and fatigue during DBT reading.
Screening training efficiency highly relies on appropriate interaction and feedbacks provided dur... more Screening training efficiency highly relies on appropriate interaction and feedbacks provided during training.1,2 A dedicated screening workstation and dedicated viewing software are de rigour for UK breast cancer screener training. These workstation and software are mainly manufactured by leading international vendors without critical technical aspects divulged to allow integrating 3rd party screener training solutions. A non-wearable AR approach has been developed and its accuracy has been quantitatively identified. As a follow-up, this study has refactored previous approaches on the wearable platform, Hololens. Wearable AR solutions are considerably user-friendly in degrees of freedom movements whilst they are seamlessly integrated and less customisable. It has not been aware that screening-suitable room-scale AR approaches have been developed and adopted. However, wearable AR techniques have relatively sophisticated apparatus developed for personal usage. In this study, Hololens...
Prostate cancer is the most common cancer in men and a leading cause of morbidity and mortality g... more Prostate cancer is the most common cancer in men and a leading cause of morbidity and mortality globally. To ensure that men receive an accurate prostate cancer diagnosis, we developed the PRISM App, a web-based self-assessment platform designed for clinicians to increase their confidence in the use of mpMRI before biopsy. The App, which provided participants with a prostate sector map, anonymous patient’s clinical history and mpMRI technical information, was tested by three radiologists of different mpMRI experience. Participants determined the number of lesions that were present in a set of twenty prostate mpMRI images, by marking and describing their location on the map. They were also asked to decide on the radiological classification, using a five-point Likert scale, and record the T-stage. Participants' screening performance was calculated by two sets of measures based on a) expert’s opinion regarding whether a case should be recalled for further investigation or not and b...
Medical Imaging 2017: Image Perception, Observer Performance, and Technology Assessment, 2017
The UK's Breast Screening Programme is 27 years old and many experienced breast radiologists are ... more 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.
Theoretical and Applied Aspects of Eye Movement Research, Selected/Edited Proceedings of The Second European Conference on Eye Movements, 1984
Summary Recording of gaze direction of experienced aircraft pilots with the NAC EYE MARK RECORDER... more Summary Recording of gaze direction of experienced aircraft pilots with the NAC EYE MARK RECORDER permits describing an optimal visual behavior in instrument and visual flight. Results lead to suggestions for the design and correction ergonomics of new visual information display modes. An analysis of visual behaviors of pilot students shows that the acquisition of the optimal behavior is progressive and unconscious. To improve the training of these students, it is suggested to use gaze direction recordings in two ways : one is to show students the optimal behavior of expert pilots, the other is to show students their own behavior.
Medical Imaging 2020: Image Perception, Observer Performance, and Technology Assessment, 2020
Pathology in the UK is on the verge of transformation from analogue to digital practice through t... more Pathology in the UK is on the verge of transformation from analogue to digital practice through the development of digital pathology (DP). Advances in technology has allowed for this change to occur through the use of high-throughput slide scanners to obtain whole histopathology glass slides onto computer workstations rather than the use of a conventional light microscope (LM). Previous studies have shown that the use of digital imaging to view histopathology slides has proven to be of benefit to pathology departments. It allows pathologists to analyse samples remote from the laboratory, making sharing of the slides between pathologists more straight-forward, and also enables expert review out of hours. With the ability to electronically transfer slides from the laboratory to the reporting pathologist, it may provide solutions for local shortages of pathologists across NHS trusts in the UK. However, a number of researchers argue that the costs of implementing digital pathology may outweigh its advantages. Moreover, images produced by DP systems are often of inferior resolution when compared to conventional light microscopy. The lack of literature on this subject limits the adoption of this new technology by laboratories across the country. This multi-centre study aims to analyse how the study pathologists examine DP images of different pathology modalities by using eye-tracking technology, thus using data on their reading and interpretation technique to improve performance and contribute to the adoption of DP across the UK.
Springer eBooks, 2017
The conventional 'keyboard and workstation' approach allows complex medical image presentation an... more The conventional 'keyboard and workstation' approach allows complex medical image presentation and manipulation during mammographic interpretation. Nevertheless, providing rich interaction and feedback in real time for navigational training or computer assisted detection of disease remains a challenge. Through computer vision and state of the art AR (Augmented Reality) technique, this study proposes an 'AR mammographic workstation' approach which could support workstationindependent rich interaction and real-time feedback. This flexible AR approach explores the feasibility of facilitating various mammographic training scenes via AR as well as its limitations.
A dedicated workstation and its corresponding viewing software are essential requirements in brea... more A dedicated workstation and its corresponding viewing software are essential requirements in breast screener training. A major challenge of developing further generic screener training technology (in particular, for mammographic interpretation training) is that high-resolution radiological images are required to be displayed on dedicated workstations whilst actual reporting of the images is generally completed on individual standard workstations. Due to commercial reasons, dedicated clinical workstations manufactured by leading international vendors tend not to have critical technical aspects divulged which would facilitate further integration of third party generic screener training technology. With standard workstations, it is noticeable that the conventional screener training depends highly on manual transcription so that traditional training methods can potentially be deficient in terms of real-time feedback and interaction. Augmented reality (AR) provides the ability to cooperate with both real and virtual environments, and therefore can supplement conventional training with virtual registered objects and actions. As a result, realistic screener training can cooperate with rich feedback and interaction in real time. Previous work 1 has shown that it is feasible to employ an AR approach to deliver workstation-independent radiological screening training by superimposing appropriate feedback coupled with the use of interaction interfaces. The previous study addressed presence issues and provided an AR recognisable stylus which allowed for drawing interaction. As a follow-up, this study extends the AR method and investigates realistic effects and the impacts of environmental illumination, application performance and transcription. A robust stylus calibration method is introduced to address environmental changes over time. Moreover, this work introduces a completed AR workflow which allows real time recording, computer analysable training data and further recoverable transcription during post-training. A quantitative evaluation results show an accuracy of more than 80% of user-drawn points being located within a pixel distance of 5.
International Journal of Information Technology and Computer Science, Aug 8, 2018
Under the Digital Image and Communication in Medicine (DICOM) standard, the Advanced Encryption S... more Under the Digital Image and Communication in Medicine (DICOM) standard, the Advanced Encryption Standard (AES) is used to encrypt medical image pixel data. This highly sensitive data needs to be transmitted securely over networks to prevent data modification. Therefore, there is ongoing research into how well encryption algorithms perform on medical images and whether they can be improved. In this paper, we have developed an algorithm using a chaotic map combined with AES and tested it against AES in its standard form. This comparison allowed us to analyse how the chaotic map affected the encryption quality. The developed algorithm, CAT-AES, iterates through Arnold's cat map before encryption a certain number of times whereas, the standard AES encryption does not. Both algorithms were tested on two sets of 16-bit DICOM images: 20 brain MRI and 26 breast cancer MRI scans, using correlation coefficient and histogram uniformity for evaluation. The results showed improvements in the encryption quality. When encrypting the images with CAT-AES, the histograms were more uniform, and the absolute correlation coefficient was closer to zero for the majority of images tested on.
Proceedings of SPIE, Mar 10, 2017
Appropriate feedback plays an important role in optimising mammographic interpretation training w... more Appropriate feedback plays an important role in optimising mammographic interpretation training whilst also ensuring good interpretation performance. The traditional keyboard, mouse and workstation technical approach has a critical limitation in providing supplementary image-related information and providing complex feedback in real time. Augmented Reality (AR) provides a possible superior approach in this situation, as feedback can be provided directly overlaying the displayed mammographic images so making a generic approach which can also be vendor neutral. In this study, radiological feedback was dynamically remapped virtually into the real world, using perspective transformation, in order to provide a richer user experience in mammographic interpretation training. This is an initial attempt of an AR approach to dynamically superimpose pre-defined feedback information of a DICOM image on top of a radiologist's view, whilst the radiologist is examining images on a clinical workstation. The study demonstrates the feasibility of the approach, although there are limitations on interactive operations which are due to the hardware used. The results of this fully functional approach provide appropriate feedback/image correspondence in a simulated mammographic interpretation environment. Thus, it is argued that employing AR is a feasible way to provide rich feedback in the delivery of mammographic interpretation training.
Proceedings of SPIE, Mar 10, 2017
The British journal of radiology, Jan 11, 2015
To compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT)... more To compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT) for assessment of soft tissue mammographic abnormalities. Women recalled for further assessment of soft tissue abnormalities were recruited and received standard supplementary views (typically spot compression views) and two view GE DBT. The added value of DBT in the assessment process was determined by analysing data collected prospectively by radiologists working up the cases. Following anonymisation of cases, there was also a retrospective multireader review. The readers first read bilateral standard two view digital mammography (DM) together with the supplementary mammographic views and gave a combined score for suspicion of malignancy on a five point scale. The same readers then read bilateral standard two view DM together with two view DBT. Pathology data was obtained. Differences were assessed using ROC analysis. The study population was 342 lesions in 322 patients. Final diagnos...
Clinical Radiology, Mar 1, 2017
Diagnostic and Prognostic Research, 2017
Diagnostic and Prognostic Research, 2017
Background: The Test-Treatment Pathway has been proposed as a method to link test accuracy to dow... more Background: The Test-Treatment Pathway has been proposed as a method to link test accuracy to downstream outcomes. By describing the clinical actions before and after testing, it illustrates how a test is positioned in the pathway, relative to other tests and diagnostics, and how the introduction of a new test may change the current diagnostics pathway. However, there is limited practical guidance on how to model such Test-Treatment Pathways. Methods: We selected the Patient-Index test-Comparator-Outcome (PICO) format, as also used elsewhere in evidence-based medicine, as a starting point for building the Test-Treatment Pathways. From there we developed a structured set of triggering questions. We defined these questions based on several brainstorm sessions and iteratively made changes to this basic structure after three rounds of user testing. During the user testing meetings, a pathway was drawn for each specific application. All sessions were recorded both on audio and video. Results: We present examples of four different Test-Treatment Pathways. User testing revealed that all users found the process of drawing the pathway very useful, but they also felt that this is just the first step in a process. The steps from pathway derivation to key questions remains difficult. Challenges in deriving the pathway were that interviewee(s) may wander off topic and that some problems cannot be captured in only one pathway. Further training was deemed desirable. Users would also like to see an electronic tool. They had no clear preference when offered a choice between a more open interviewing approach versus a more closed checklist approach. Discussion: Modelling Test-Treatment pathways is a useful step in synthesizing the evidence about medical tests and developing recommendations about them, but further technical development and training are needed to facilitate their use in evidence-based medicine. O2 Using machine learning and crowdsourcing for the identification of diagnostic test accuracy
Breast Cancer Research, 2015
Introduction: The aim was to compare the accuracy of standard supplementary views and GE digital ... more Introduction: The aim was to compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT) for assessment of soft tissue mammographic abnormalities. Methods: Women recalled for further assessment of soft tissue abnormalities were recruited and received standard supplementary views (typically spot compression views) and two-view GE DBT. The added value of DBT in the assessment process was determined by analysing data collected prospectively by unblinded radiologists working up the cases. Following anonymisation of cases, there was also a retrospective multireader review. The readers first read bilateral standard two-view digital mammography (DM) together with the supplementary mammographic views and gave a combined score for suspicion of malignancy on a fivepoint scale. The same readers then read bilateral standard two-view DM together with two-view DBT. Pathology data were obtained. Differences were assessed using ROC analysis. Results: The study population was 342 lesions in 322 patients. Final diagnosis was malignant in 113 cases (33%) and benign/normal in 229 cases (67%). In the prospective analysis, the performance of two-view DM plus DBT was at least equivalent to the performance of two-view DM and standard mammographic supplementary views-area under the curve (AUC) was 0.946 and 0.922 respectively, which did not reach statistical significance. Similar results were obtained for the retrospective review-AUC was 0.900 (DBT) and 0.873 (supplementary views), which did not reach statistical significance. Conclusion: The accuracy of GE DBT in the assessment of screendetected soft tissue abnormalities is equivalent to the use of standard supplementary mammographic views.
Behavior Research Methods Instruments & Computers, Nov 1, 2002
Background to the Project This paper describes the design and construction of an eye-tracking exh... more Background to the Project This paper describes the design and construction of an eye-tracking exhibit and experiment that was part of a public exhibitionentitled "Telling Time" at the National Gallery, London, from October 18, 2000 to January 14, 2001. Designed and built by the Applied Vision Research Unit of the University of Derby, the exhibit functioned as a controlled eye movement experiment on a large number of participants, providing a wealth of data on how individuals look at images in general and at paintings in particular. Its aim also was to illustrate to members of the public that viewing a picture is not an instantaneous process but that our understanding of the image develops as we stand before it. Although there have been eye-tracking exhibits in museums and science centers around the world (see, e.g., Buquet, Charlier, & Paris, 1988; Glenstrup & Engell-Nielsen,1995; and see Appendix A), these have focused on the eye tracker as a public science exhibit, rather than being used to gather scientific data. The Demands of the Exhibit The exhibit as experiment. The exhibit was designed to function as a scientifically rigorous experiment that would record the eye movements of large numbers of individuals as they viewed images of paintings. Traditional eye movement experiments use relatively small numbers of participants. With a large number of participants, the data could be generalized widely, with each stimulus being observed by more than 100 participants. The experiment as exhibit. To encourage participation, the exhibit was as interactive as possible. A large "public" display alongside the exhibit was controlled by the same computer that was running both the experiment and the eye-tracking system and displayed the live eye movements of the current participant. Each participant's eye movements were also replayed while the next participant was undergoing the necessary calibration process. When no current data were available, the public display replayed prerecorded traces or showed more complex representations of eye movement data. Participants. The participants were self-selected visitors to the exhibition.Data from 1995/1996 show approximately equal numbers of men and women visitors to the Gallery, peakingin the 15-to 34-year-old group. Recordingeye movements is more difficult in older participants, so a preponderance of the young among visitors was favorable. The project was approved by the University Ethics Committee, and the self-selecting participants were informed of the purpose of the experiment through carefully worded static displays accompanying the exhibit. Requirements of the design. As exhibitvisitors, the participants were typically "naive," with no prior knowledge of eye movements or of the purpose of the experiment. Consequently, in use, the exhibit needed to be intuitive and user-friendly, with minimal per-participant time, while maximizing the experimental and exhibition properties. The main challenge of the exhibit was to record eye movements automatically from a wide range of people without being intrusive, intimidating, or uncomfortable. Recording eye movements typically requires a skilled human operator, but the autonomous system had to operate unattended and with minimal operator interventionfor the 3-month duration of the exhibition.
Medical Imaging 2021: Image Perception, Observer Performance, and Technology Assessment, 2021
The UK national screening program for breast cancer currently uses Full Field Digital Mammography... more The UK national screening program for breast cancer currently uses Full Field Digital Mammography (FFDM). Various studies have shown that DBT has a higher sensitivity and specificity in identifying early breast cancer apart from benign pathologies, even in very dense breasts. This potentially makes DBT a better screening modality to detect early breast cancer, as well as minimize false positive recall rates. However, DBT has multiple image slices and thereby makes reading cases inherently a longer and potentially more visually fatiguing task. Our previous studies (Dong et al, 2017 and 2018) have demonstrated the impact of institutional training on reading techniques in DBT. The reading technique itself appears to have an effect on total reading time. In other follow-on studies we have employed eye tracking which gives rise to complex data sets, including parameters such as eyelid opening and pupil diameter measures, which can then be employed to gauge blinks and fatigue onset. Findings from this work have guided changes in our blink identification techniques and we have now developed semi-automated programmed processes which can analyze the large data set and provide a more accurate assessment of fatigue and vigilance parameters through blink detection. Here, we have considered ‘eyelid opening’ parameters of both the left and the right eye separately. Having such a separated approach allowed us to tease out particular aspects of blinking. Similar to Schleicher et al (2008), we found there to be ultra-short blinks (30-50 milli seconds), short blinks (51- 100 msecs), long blinks (101-500 msecs) and also microsleeps (>500 msecs). We argue that the changes observed in the frequencies of these blinks can be used as a measure of vigilance and fatigue during DBT reading.
Screening training efficiency highly relies on appropriate interaction and feedbacks provided dur... more Screening training efficiency highly relies on appropriate interaction and feedbacks provided during training.1,2 A dedicated screening workstation and dedicated viewing software are de rigour for UK breast cancer screener training. These workstation and software are mainly manufactured by leading international vendors without critical technical aspects divulged to allow integrating 3rd party screener training solutions. A non-wearable AR approach has been developed and its accuracy has been quantitatively identified. As a follow-up, this study has refactored previous approaches on the wearable platform, Hololens. Wearable AR solutions are considerably user-friendly in degrees of freedom movements whilst they are seamlessly integrated and less customisable. It has not been aware that screening-suitable room-scale AR approaches have been developed and adopted. However, wearable AR techniques have relatively sophisticated apparatus developed for personal usage. In this study, Hololens...
Prostate cancer is the most common cancer in men and a leading cause of morbidity and mortality g... more Prostate cancer is the most common cancer in men and a leading cause of morbidity and mortality globally. To ensure that men receive an accurate prostate cancer diagnosis, we developed the PRISM App, a web-based self-assessment platform designed for clinicians to increase their confidence in the use of mpMRI before biopsy. The App, which provided participants with a prostate sector map, anonymous patient’s clinical history and mpMRI technical information, was tested by three radiologists of different mpMRI experience. Participants determined the number of lesions that were present in a set of twenty prostate mpMRI images, by marking and describing their location on the map. They were also asked to decide on the radiological classification, using a five-point Likert scale, and record the T-stage. Participants' screening performance was calculated by two sets of measures based on a) expert’s opinion regarding whether a case should be recalled for further investigation or not and b...
Medical Imaging 2017: Image Perception, Observer Performance, and Technology Assessment, 2017
The UK's Breast Screening Programme is 27 years old and many experienced breast radiologists are ... more 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.
Theoretical and Applied Aspects of Eye Movement Research, Selected/Edited Proceedings of The Second European Conference on Eye Movements, 1984
Summary Recording of gaze direction of experienced aircraft pilots with the NAC EYE MARK RECORDER... more Summary Recording of gaze direction of experienced aircraft pilots with the NAC EYE MARK RECORDER permits describing an optimal visual behavior in instrument and visual flight. Results lead to suggestions for the design and correction ergonomics of new visual information display modes. An analysis of visual behaviors of pilot students shows that the acquisition of the optimal behavior is progressive and unconscious. To improve the training of these students, it is suggested to use gaze direction recordings in two ways : one is to show students the optimal behavior of expert pilots, the other is to show students their own behavior.
Medical Imaging 2020: Image Perception, Observer Performance, and Technology Assessment, 2020
Pathology in the UK is on the verge of transformation from analogue to digital practice through t... more Pathology in the UK is on the verge of transformation from analogue to digital practice through the development of digital pathology (DP). Advances in technology has allowed for this change to occur through the use of high-throughput slide scanners to obtain whole histopathology glass slides onto computer workstations rather than the use of a conventional light microscope (LM). Previous studies have shown that the use of digital imaging to view histopathology slides has proven to be of benefit to pathology departments. It allows pathologists to analyse samples remote from the laboratory, making sharing of the slides between pathologists more straight-forward, and also enables expert review out of hours. With the ability to electronically transfer slides from the laboratory to the reporting pathologist, it may provide solutions for local shortages of pathologists across NHS trusts in the UK. However, a number of researchers argue that the costs of implementing digital pathology may outweigh its advantages. Moreover, images produced by DP systems are often of inferior resolution when compared to conventional light microscopy. The lack of literature on this subject limits the adoption of this new technology by laboratories across the country. This multi-centre study aims to analyse how the study pathologists examine DP images of different pathology modalities by using eye-tracking technology, thus using data on their reading and interpretation technique to improve performance and contribute to the adoption of DP across the UK.