This dissertation addresses two problems dealing with detection sensitivity in radiology. First, is a 100-mm format adequate for displaying enhanced radiographic images in a photoelectronic imaging system and can the same format be used for permanent storage of these images? Second, what are the effects of training on the radiologist's sensitivity? Controlled 14-in. x 17-in. x-ray images were reduced to 100 mm to investigate which factors caused the decrement noted in the radiology literature. The 14-in. x 17-in. images used were generated from a 3M phantom. Three levels of kilovolt potential (80 kVp, 110 kVp, and 140 kVp) and two types of film (RPR and Cronex) were used to make the images. Twenty-four images, six for each of four quadrants, contained a simulated lung nodule and six contained no nodule. The 100-mm images were precisely controlled, miniaturized images of the above films. The task of the 16 non-radiologists was to decide if a simulated nodule was present or not. A signal detection experimental paradigm with a 10-point certainty scale was used for analysis. Correction for location was also implemented. For the first problem, results showed that kilovolt potential and film type interacted with the reduction procedure to change the direction of sensitivity (both in the positive and the negative directions) in the reduced format stimulus set, thereby indicating that the 100-mm format was not the main reason for reduced sensitivity noted in the literature. Our conclusion was that the 100-mm format would be suitable for image enhancement displays and for permanent hard copy in a photoelectronic radiologic imaging system. The second problem explores the effects of training on detection and sensitivity. The responses of the untrained observers to the 14-in. x 17-in. images were compared to previously gathered data of the staff and residents of the Arizona Health Sciences Center Radiology Department. Results indicated that the residents, even before formal training, were much better than the untrained observers, but well below the staff, in detection sensitivity. Within 6 months to a year later, they were equivalent to the staff. The main conclusion was that sensitivity does increase with training fairly rapidly and that the findings would be useful in designing further studies to investigate means to speed up or enhance the procedures used to train new radiologists.

Submitted in fulfillment of the requirements for the Degree of Master of Health Sciences in Radiography, Durban University of Technology, 2017. / Background The current scope of practice for diagnostic radiographers, does not allow them to administer intravenous contrast media (IVCM) since there are no formal training guidelines accredited by the Health Professions Council of South Africa (HPCSA) (Koch 2014: 26). In selected countries abroad, radiographers are allowed to administer IVCM and have thus received the necessary and accredited training to do so. In view of this, the South African radiographer’s scope of practice is not on par with the selected countries. The radiologists in South Africa (SA) who are currently responsible for the administration of IVCM have issued a position statement which supports, in principle, the idea of radiographers administering IVCM should they receive the necessary and appropriate training to do so (RSSA 2011: 1-2). The aim of this research study was, therefore, to investigate the radiologists’ perspectives regarding the theoretical knowledge, clinical competencies and medico legal responsibilities required by radiographers in order to effectively administer IVCM. This research study provides input for the development of national training guidelines for radiographers to administer IVCM. Research Methodology A quantitative, descriptive study was conducted by targeting qualified radiologists residing and practicing within the province of KwaZulu Natal (KZN). Ethical approval was obtained from the Durban University of Technology’s (DUT) Institutional Research and Ethics Committee (IREC). All the participants were contacted in their personal capacity. The research tool was an online survey administered through SurveyMonkey which included questions and statements relating to the administration of IVCM and was structured so as to meet the study objectives. The research tool was evaluated and amended by an expert focus group to ensure reliability and validity. Confidentiality was maintained and all the data obtained during this research study was password protected. Results and discussion Fifty-nine radiologists (60.8 percent) participated in this study. Twelve respondents, however, were excluded due to incomplete surveys. The final response rate, therefore, was 48.5 percent (n=47) of which 72.3 percent of the respondents were from the private sector. Results illustrated the radiologists’ agreement regarding the theoretical, clinical/practical and medico legal training components for inclusion in the further training of radiographers to administer IVCM. Most respondents supported the inclusion of three assessments: theoretical (87.2 percent), clinical (93.6 percent) and a record of clinical competencies (95.7 percent). The assessments were considered equally important in terms of percentage weighting. The overall results compared favorably to the current international trends and practice standards of radiographers administering IVCM. Conclusion and Recommendations The study, in providing key data for the development of training guidelines for radiographers to administer IVCM, has demonstrated the importance of higher education (HE) and training in addressing transformation in health services with particular reference to professional scopes of practice. Furthermore, it reinforces the need for local research that will inform HE and training and hence a scope of practice that meets local needs. It was recommended that future studies should include those HE institutions offering training in Radiography as well as their stakeholders for the design and transformation of a national curriculum for radiographers to administer IVCM. / M