NEW TOOLS FOR MONITORING GAMMA CAMERA UNIFORMITY

Detector uniformity is a fundamental performance characteristic of all modern gamma camera systems, and ensuring a stable, uniform detector response is critical for maintaining clinical images that are free of artifact. For these reasons, the assessment of detector uniformity is one of the most common activities associated with a successful clinical quality assurance program in gamma camera imaging. The evaluation of this parameter, however, is often unclear because it is highly dependent upon acquisition conditions, reviewer expertise, and the application of somewhat arbitrary limits that do not characterize the spatial location of the non-uniformities. Furthermore, as the goal of any robust quality control program is the determination of significant deviations from standard or baseline conditions, clinicians and vendors often neglect the temporal nature of detector degradation (1). This thesis describes the development and testing of new methods for monitoring detector uniformity. These techniques provide more quantitative, sensitive, and specific feedback to the reviewer so that he or she may be better equipped to identify performance degradation prior to its manifestation in clinical images. The methods exploit the temporal nature of detector degradation and spatially segment distinct regions-of-non-uniformity using multi-resolution decomposition. These techniques were tested on synthetic phantom data using different degradation functions, as well as on experimentally acquired time series floods with induced, progressively worsening defects present within the field-of-view. The sensitivity of conventional, global figures-of-merit for detecting changes in uniformity was evaluated and compared to these new image-space techniques. The image-space algorithms provide a reproducible means of detecting regions-of-non-uniformity prior to any single flood image’s having a NEMA uniformity value in excess of 5%. The sensitivity of these image-space algorithms was found to depend on the size and magnitude of the non-uniformities, as well as on the nature of the cause of the non-uniform region. A trend analysis of the conventional figures-of-merit demonstrated their sensitivity to shifts in detector uniformity. The image-space algorithms are computationally efficient. Therefore, the image-space algorithms should be used concomitantly with the trending of the global figures-of-merit in order to provide the reviewer with a richer assessment of gamma camera detector uniformity characteristics.

Revising the National Ambient Air Quality Standards: The integration of science and policy

Under the Clean Air Act, Congress granted discretionary decision making authority to the Administrator of the Environmental Protection Agency (EPA). This discretionary authority involves setting standards to protect the public's health with an "adequate margin of safety" based on current scientific knowledge. The Administrator of the EPA is usually not a scientist, and for the National Ambient Air Quality Standard (NAAQS) for particulate matter (PM), the Administrator faced the task of revising a standard when several scientific factors were ambiguous. These factors included: (1) no identifiable threshold below which health effects are not manifested, (2) no biological basis to explain the reported associations between particulate matter and adverse health effects, and (3) no consensus among the members of the Clean Air Scientific Advisory Committee (CASAC) as to what an appropriate PM indicator, averaging period, or value would be for the revised standard. ^ This project recommends and demonstrates a tool, integrated assessment (IA), to aid the Administrator in making a public health policy decision in the face of ambiguous scientific factors. IA is an interdisciplinary approach to decision making that has been used to deal with complex issues involving many uncertainties, particularly climate change analyses. Two IA approaches are presented; a rough set analysis by which the expertise of CASAC members can be better utilized, and a flag model for incorporating the views of stakeholders into the standard setting process. ^ The rough set analysis can describe minimal and maximal conditions about the current science pertaining to PM and health effects. Similarly, a flag model can evaluate agreement or lack of agreement by various stakeholder groups to the proposed standard in the PM review process. ^ The use of these IA tools will enable the Administrator to (1) complete the NAAQS review in a manner that is in closer compliance with the Clean Air Act, (2) expand the input from CASAC, (3) take into consideration the views of the stakeholders, and (4) retain discretionary decision making authority. ^

Measuring the quality of life of patients with diabetes: Validating the tool and determining the effects on quality of life

There are several tools for measuring quality of life (QoL) and specifically, health-related quality of life (HRQoL) for persons with diabetes. A commonly-used measure, the Diabetes Quality of Life (DQOL) Survey, developed for the Diabetes Control and Complications Trial (DCCT), has been used in several experimental settings, and its reliability and validity are well-established. However, it is considered too long to be of practical use in clinical settings. Because of this, a shortened version of the tool was used recently in the Community Diabetes Education (CoDE) Project in Dallas, Texas, a clinic-based patient education program that uses a specially-trained community healthcare worker to provide patient education. However, the modified scale has never been tested for reliability and validity. Thus, one goal of this thesis was to measure these psychometric properties of the scale. After establishing the reliability and validity, the results of the scale were analyzed to determine the effects of the intervention on the subjects’ quality of life. The changes in QoL scales were compared with changes in physiologic measures which are most closely allied with diabetes, including blood glucose levels, weight/BMI, co-morbidities and health beliefs in order to determine if there is a relationship between such measures and quality of life. The results of the reliability and validity testing were not conclusive. Measures of reliability and criterion validity were established, but these contrasted with poor measures of repeatability and content validity. The effect of the intervention on quality of life, however, was more significant, particularly regarding the impact of diabetes. Those who received the counseling had significantly higher scores on the Impact scale than those who did not, and the former group had much greater improvement in scores over the twelve month period than the latter group. ^

A qualitative analysis of leadership styles and the selection of quality improvement in primary care practice

In the Practice Change Model, physicians act as key stakeholders, people who have both an investment in the practice and the capacity to influence how the practice performs. This leadership role is critical to the development and change of the practice. Leadership roles and effectiveness are an important factor in quality improvement in primary care practices.^ The study conducted involved a comparative case study analysis to identify leadership roles and the relationship between leadership roles and the number and type of quality improvement strategies adopted during a Practice Change Model-based intervention study. The research utilized secondary data from four primary care practices with various leadership styles. The practices are located in the San Antonio region and serve a large Hispanic population. The data was collected by two ABC Project Facilitators from each practice during a 12-month period including Key Informant Interviews (all staff members), MAP (Multi-method Assessment Process), and Practice Facilitation field notes. This data was used to evaluate leadership styles, management within the practice, and intervention tools that were implemented. The chief steps will be (1) to analyze if the leader-member relations contribute to the type of quality improvement strategy or strategies selected (2) to investigate if leader-position power contributes to the number of strategies selected and the type of strategy selected (3) and to explore whether the task structure varies across the four primary care practices.^ The research found that involving more members of the clinic staff in decision-making, building bridges between organizational staff and clinical staff, and task structure are all associated with the direct influence on the number and type of quality improvement strategies implemented in primary care practice.^ Although this research only investigated leadership styles of four different practices, it will offer future guidance on how to establish the priorities and implementation of quality improvement strategies that will have the greatest impact on patient care improvement. ^

Can accreditation work as a tool for quality improvement in public health? A critical review

Public health departments play an important role in promoting and preserving the health of communities. The lack of a system to ensure their quality and accountability led to the development of a national voluntary accreditation program by Public Health Accreditation Board (PHAB). The concept that accreditation will lead to quality improvement in public health which will ultimately lead to healthy communities seems intuitive but lacks a robust body of evidence. A critical review of literature was conducted to explore if accreditation can lead to quality improvement in public health. The articles were selected from publically available databases using a specific set of criteria for inclusion, exclusion, and appraisal. To understand the relationship between accreditation and quality improvement, the potential strengths and limitations of accreditation process were evaluated. Recommendations for best practices are suggested so that public health accreditation can yield maximum benefits. A logic model framework to help depict the impact of accreditation on various levels of public health outcomes is also discussed in this thesis. The literature review shows that existing accreditation programs in other industries show limited but encouraging evidence that accreditation will improve quality and strengthen the delivery of public health services. While progress in introducing accreditation in public health can be informed by other accredited industries, the public health field has its own set of challenges. Providing incentives, creating financing strategies, and having a strong leadership will allow greater access to accreditation by all public health departments. The suggested recommendations include that continuous evaluation, public participation, systems approach, clear vision, and dynamic standards should become hallmarks of the accreditation process. Understanding the link between accreditation, quality improvement, and health outcomes will influence the successful adoption and implementation of the public health accreditation program. This review of literature suggests that accreditation is an important step in improving the quality of public health departments and in ultimately improving the health of communities. However, accreditation should be considered in an integrated system of tools and approaches to improve the public health practice. Hence, it is a means to an end - not an end unto itself.^