A gaze-contingent framework for perceptually-enabled applications in healthcare

Patient safety and quality of care remain the focus of the smart operating room of the future. Some of the most influential factors with a detrimental effect are related to suboptimal communication among the staff, poor flow of information, staff workload and fatigue, ergonomics and sterility in the operating room. While technological developments constantly transform the operating room layout and the interaction between surgical staff and machinery, a vast array of opportunities arise for the design of systems and approaches, that can enhance patient safety and improve workflow and efficiency. The aim of this research is to develop a real-time gaze-contingent framework towards a "smart" operating suite, that will enhance operator's ergonomics by allowing perceptually-enabled, touchless and natural interaction with the environment. The main feature of the proposed framework is the ability to acquire and utilise the plethora of information provided by the human visual system to allow touchless interaction with medical devices in the operating room. In this thesis, a gaze-guided robotic scrub nurse, a gaze-controlled robotised flexible endoscope and a gaze-guided assistive robotic system are proposed. Firstly, the gaze-guided robotic scrub nurse is presented; surgical teams performed a simulated surgical task with the assistance of a robot scrub nurse, which complements the human scrub nurse in delivery of surgical instruments, following gaze selection by the surgeon. Then, the gaze-controlled robotised flexible endoscope is introduced; experienced endoscopists and novice users performed a simulated examination of the upper gastrointestinal tract using predominately their natural gaze. Finally, a gaze-guided assistive robotic system is presented, which aims to facilitate activities of daily living. The results of this work provide valuable insights into the feasibility of integrating the developed gaze-contingent framework into clinical practice without significant workflow disruptions.Open Acces

Dose optimization in diagnostic radiology

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree for the Doctor of Philosophy. Johannesburg 2012Medical X-ray imaging is nowadays ubiquitous in healthcare. International studies have shown that patient doses during both diagnostic X-ray examinations and fluoroscopically guided procedures from one clinic to another can vary by a factor of up to 100. Such a variation in patient doses offers an opportunity for dose – image quality optimization. Given this background, every radiology clinic which wants to use X-ray imaging ethically and efficiently should have in place ways of optimizing the patient dose – image quality relationship. One generally accepted tool in the optimization process is diagnostic reference levels (DRLs). Currently in South Africa there are no established DRLs and there is no systematic patient dose data collection by the either the national regulator or any competent authority. The main purpose of this thesis was to quantify patient doses for patients undergoing diagnostic examinations and fluoroscopically guided procedures, educate radiation workers on typical patient doses, develop effective methods in quality control of radiographic and fluoroscopic equipment and evaluate radiographer familiarity with digital radiography technology within the context of a typical university teaching South African hospital. The present thesis comprises of seven studies, all carried out at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH), formerly Johannesburg Hospital: Study I: In this investigation the luminance level of X-ray viewing boxes and ambient lighting levels in reporting rooms were measured as a quality assurance procedure and compared with the recommended values by the Directorate of Radiation Control (DRC) of South Africa, European Commission (EC) and Nordic Radiation Protection Co-operation (NORDIC). Results from this investigation showed that the mean average luminance was 1027 cd m-2 and 3284 cd m-2 at the Division of Radiology and Division of Radiation Oncology respectively. The Division of Radiation Oncology had an average viewing box uniformity 7.14% compared to 27.32% at the Division of Radiology. The average ambient lighting was found to be 66 lux for both Divisions. The radiograph viewing conditions variably comply with guidelines. The radiographic imaging chain can only be as strong as its weakest link, thus this study underscores the need of implementing quality control and quality assurance standards in radiographic image viewing. Based on the practical experience of this investigation it is recommended that the DRC test criteria be adopted, in light of the varied recommendations worldwide. Study II: This study aimed to develop, implement and evaluate a software program which can be used in a radiology quality control program. A Microsoft Excel™ based software program was developed for use in quality control: tests data collection, analysis and archiving of the tests done on general radiography equipment, fluoroscopy equipment and film processors. Validation of the software application in terms of usability, user-friendliness was done by an experienced radiographer. This software provides an easier and efficient way of recording quality control data, analysis and archiving. Study III: This study retrospectively analyzed the radiation doses delivered to patients undergoing fluoroscopy guided procedures in terms of the skin dose1 and the kerma-area product readings. A total of three hundred and thirty one fluoroscopically guided procedures were analyzed. In agreement with other published studies, a weak correlation was shown between skin dose and screening time, while a poor correlation was shown between KAP reading and screening time. There was a wide spread in the radiation doses registered for any one given type of examination, which shows that there is room for dose optimization. From the lessons drawn from this study it is practically feasible to record the KAP, fluoroscopy time and number of images routinely. The usefulness and potential use of KAP meters with regards to dose optimization in radiology was confirmed. Study IV: This investigation aimed to assess the feasibility of fabricating in-house the clinical dosimetry radiology phantoms. A total of six patient dose assessment phantoms were fabricated of which four phantoms were as per American National Standards Institute (ANSI) specifications and the other two as per Centre for Devices and Radiological Health (CDRH) specifications. This study proved that the phantoms can be fabricated cost-effectively in-house in a hospital with a mechanical engineering workshop using materials which are locally available. In addition, this study determined radiation doses received by patients undergoing six general radiography examinations. The feasibility of both direct and indirect methods of patient dosimetry was studied. Patient dosimetry based on indirect measurements was the method of choice. Patient data and technical parameters related to the X-ray examinations were collected. The study involved the following examinations: chest posterior-anterior (PA), chest lateral (LAT), pelvis anterior-posterior (AP), abdomen AP, lumbar spine AP and thoracic spine AP. Entrance surface air kerma was calculated based on the X-ray tube 1 See Section 8.3 on the use of the term skin dose output of the unit used and the exposure parameters used for the actual examination. Based on the mean entrance surface air kerma (ESAK) values from the individual rooms, the following DRLs were established: 0.10 mGy for chest PA, 0.22 mGy for chest LAT, 2.98 mGy for pelvis AP, 4.19 mGy for abdomen AP, 5.30 mGy for lumbar spine AP and 3.28 mGy for thoracic spine AP. The calculated mean ESAK values were compared with previously published mean values from other countries. For the first time, a baseline for potential dose reference levels (DRLs) in South Africa was established for the selected examinations. The results of this snapshot audit serve as a benchmark for future dose optimization attempts in South Africa. Feasible and practical dose saving measures are presented and discussed based on the experience of the present patient dose audit carried out. Study V: A replica of the CDRAD phantom was successfully fabricated in-house for use as an image quality test object. It has been shown that the phantom when fabricated in-house is inexpensive and can be made from materials that are readily available locally. Furthermore the utility of the replica phantom as both an acceptance testing and routine quality control tool has been demonstrated. The replica phantom proved effective for purpose and user-friendly. Study VI: The purpose of this study was to assess radiographer familiarity and preferences with digital radiography and thereafter make recommendations in line with the migration from screen film to digital radiography in South Africa. A questionnaire was designed to collect data from either qualified or student radiographers from four teaching hospitals. From the four teaching hospitals there were a total of 205 potential respondents. Among other things, responses regarding experiences and preferences with digital radiography, quality control procedures, patient dose, advantages and disadvantages of digital radiography were sought. The information collected was based on self-reporting by the participants. Sixty-three out of 205 (31 %) radiographers from all the four radiology centres responded to the circulated questionnaire. The participants of this survey showed familiarity with digital radiography and have embraced this relatively new technology as shown by the fact that they can identify both its advantages and disadvantages as applied to clinical practice. However, there are minimal quality control procedures specific to digital radiography being undertaken and there is need for formal education, continuing education and manufacturer training with respect to quality control as institutions make the transition from conventional screen film radiology to digital radiology. Study VII: An investigation into the amount of scattered radiation from the couch during under-couch procedures was carried out. Of dosimetric concern are the forward scattered photons from the couch which contribute in principle to patient dose. Measurement of the amount of scattered radiation off the patient couch was accomplished by using an ionization chamber. The results of the investigation showed that for field size of dimensions, 10 cm * 10 cm, the scatter contribution is approximately 12 % of the total radiation reaching the patient surface. In addition the scatter contribution varies by ±2% across field sizes ranging from 8 cm * 8 cm to 20 cm * 20 cm, with the 10 cm * 10 cm field size taken as a reference field. This study underscores the need to account for the forward scattered radiation so as to improve the accuracy of clinical patient dosimetry. Programs of continuing education and training of radiological personnel in appropriate radiological technique need be actively implemented in order to maintain a high level of awareness of the factors that determine the diagnostic quality and dose to the patients. In line with efforts to optimize dose from diagnostic radiography examinations it is recommended that national DRLs be established in South Africa for the most frequent examinations in general radiography and fluoroscopy. It is recommended that the South African national regulator endeavour to implement or facilitate implementation of a national patient dose database. In summary, this thesis indicates the possibility of dose reduction in diagnostic radiology through optimization of radiographic process

A corpus based, lexical analysis of patient information for radiography

Despite the importance and the ubiquity of medical patient information in many healthcare systems in the world, we know very little about the lexical characteristics of the register. We do not know how patients perceive the information in the leaflets or whether the messages are transmitted effectively and fully understood. How a medical authority instructs and obliges patients in written information is also unclear. While the number of radiographic examinations performed globally increases year on year, studies consistently show that patients lack basic knowledge regarding the commonly-performed exams and show very poor understanding of the concomitant risks associated with radiation. There is, then, a pressing need to investigate radiography patient information in order to better understand why, and where, it is less effective. This thesis applies three approaches common to the field of corpus linguistics to uncover some of the lexical characteristics of patient information for radiography. The approaches used in this thesis are a keyword extraction, a lexical bundles analysis and an investigation of modal verbs used to express obligation. The findings suggest that patient information for radiography possesses characteristics more common to academic prose than conversation, although the high informational content of the register goes some way to explaining this and suggests that the reliance on these structures may, to a certain extent, be unavoidable. Results also suggest that the reliance on should to oblige and instruct is problematic as it may cause interpretation problems for certain patients, including those for whom English is not a primary language. Certain other characteristics of patient information revealed by the analyses may also cause comprehension, and while further research is needed, none of these characteristics would be evaluated as problematic by standard readability measures, furthering doubts about the suitability of such measures for the evaluation of medical information

The PERMIT Project: Personalised Renal Function Monitoring via Information Technology

Patients with heart failure are typically elderly and are among those most at risk of renal failure due to both their condition and their medication. Regular monitoring of renal function may allow early detection of renal decline and appropriate intervention to prevent renal failure. However, clinical guidance on renal function monitoring in heart failure is sparse and based on anecdotal evidence. To reduce unnecessary admissions caused by renal impairment in heart failure due to inadequate monitoring, standardised practice for renal monitoring would be of benefit. Given that each patient has individual co-morbidities and rates of renal decline, general guidelines may have minimal impact and there may be a need for renal monitoring that is personalised case-by-case. The aim of the PERMIT project (Personalised Renal Function Monitoring via Information Technology) was to develop the framework for creating such personalised guidance by using machine-learning on large clinical datasets. The goal was to create a prediction model that could highlight which patients with heart failure were most at risk of renal decline, in order to intervene before they required hospital admission. In light of developing a future predictive algorithm for use in clinical care, patient and clinician engagement with heart failure-related remote healthcare technologies was investigated. The aim of this was to improve the knowledge base so that future technologies, such as remote renal monitoring, can improve upon their accessibility and acceptability in this patient cohort. Studies examining remote care in heart failure were thematically synthesised in a qualitative systematic review. This generated 5 core themes of engagement: Clinical Care, Convenience, Communication, Ease of use, and Education, with different perspectives from patients and healthcare staff. The themes which were generated were assessed prospectively via a discrete-choice questionnaire survey given to heart failure patients (n=93). Binary logit analysis showed that ‘Clinical care’ was most valued by patients with heart failure and was almost twice as important as ‘Communication’, the lowest ranked theme. The study provided important insights into the lived experiences of patients with heart failure that will allow the development of future interventions with greater acceptability and engagement rates. To create the predictive model for renal decline, retrospective primary care data was obtained from SIR (Salford Integrated Records). This data was processed into a longitudinal dataset which included 3800 adult patients with newly diagnosed heart failure, over an 8.5 year study window. The clinical parameters of each patient were mapped longitudinally with creatinine over time. A model-based clustering algorithm known as ‘flexmix’ was applied to the data. In order to select appropriate clinical variables to input into the clustering predictive model, pairwise mixed-model linear regression was used to determine correlation between each clinical parameter and log(creatinine). The most correlative covariates were serum urea and serum potassium, with urea showing the highest R-squared value for explaining variance in creatinine over time. The final clustering model therefore used the inputs of: age at heart failure diagnosis; time since heart failure diagnosis; gender; IMD decile; and serum urea. This process produced seven discrete clusters of renal change over time which were ranked by severity. Evaluation of the algorithm was made using the assigned cluster models to predict creatinine over time in patients with heart failure. The MAPE (mean absolute percentage error) of the creatinine prediction was between 17-33% depending on the cluster assigned. The work outlined in this thesis represents an important step towards developing personalised renal monitoring guidance. Important clinical correlates of renal function decline, identified in the process, can be used for prognostic research in future studies. The error of the prediction values was variable and will thus require further optimisation using additional datasets and clinical studies in the future