A cloud-based system for measuring radiation treatment plan similarity

PURPOSE: Radiation therapy is used to treat cancer using carefully designed plans that maximize the radiation dose delivered to the target and minimize damage to healthy tissue, with the dose administered over multiple occasions. Creating treatment plans is a laborious process and presents an obstacle to more frequent replanning, which remains an unsolved problem. However, in between new plans being created, the patient's anatomy can change due to multiple factors including reduction in tumor size and loss of weight, which results in poorer patient outcomes. Cloud computing is a newer technology that is slowly being used for medical applications with promising results. The objective of this work was to design and build a system that could analyze a database of previously created treatment plans, which are stored with their associated anatomical information in studies, to find the one with the most similar anatomy to a new patient. The analyses would be performed in parallel on the cloud to decrease the computation time of finding this plan. METHODS: The system used SlicerRT, a radiation therapy toolkit for the open-source platform 3D Slicer, for its tools to perform the similarity analysis algorithm. Amazon Web Services was used for the cloud instances on which the analyses were performed, as well as for storage of the radiation therapy studies and messaging between the instances and a master local computer. A module was built in SlicerRT to provide the user with an interface to direct the system on the cloud, as well as to perform other related tasks. RESULTS: The cloud-based system out-performed previous methods of conducting the similarity analyses in terms of time, as it analyzed 100 studies in approximately 13 minutes, and produced the same similarity values as those methods. It also scaled up to larger numbers of studies to analyze in the database with a small increase in computation time of just over 2 minutes. CONCLUSION: This system successfully analyzes a large database of radiation therapy studies and finds the one that is most similar to a new patient, which represents a potential step forward in achieving feasible adaptive radiation therapy replanning.

Measuring Scope of Practice Enactment among Primary Care Registered Nurses in Ontario

Background: Primary care is the sector of health care in which patients first establish contact with the health system, are provided person-focused care over time for all new or common needs, and receive coordinated integrated health services provided elsewhere by other members of the health care team. Registered Nurses (RNs) in Canada provide care within this sector in varying roles. The extent to which RNs enact their full scope of practice in primary care settings in Canada is not known. The Actual Scope of Practice questionnaire (ASCOP) is a 26 item Likert scale questionnaire developed by researchers in Canada and validated in the acute care setting to measure the extent to which RNs apply the knowledge, skills and competencies of the professional full scope of practice. Similar to the acute care setting, there is a need to measure scope of practice enactment in the primary care setting. Objectives: The overall aim of this thesis was to measure scope of practice enactment in the primary care setting. Two research objectives were addressed: (1) to revise and adapt the ASCOP questionnaire for use in the primary care setting, and (2) to determine internal consistency, construct validity, and sensitivity of the modified instrument, the ASCOP-PC. Methods: To address the first objective, a narrative literature review and synthesis and an expert panel review was conducted. To address the second objective a cross-sectional survey of 178 RNs working in primary care organizations in Ontario was conducted Results: The ASCOP, with few modifications, addressed key attributes of nursing scope of practice in the primary care setting. The ASCOP-PC yielded acceptable alpha coefficients ranging from 0.66 to 0.91 and explained variances from 44.2 to 62.6. Total mean score of 5.16 suggests that RNs within these models of care almost always engage in activities reflected in the ASCOP-PC. Interpretation: Findings from this study support the use of a the modified ASCOP questionnaire as a reliable and valid measure of scope of practice enactment among primary care nurses in the primary care setting.