The International Commission of Radiological Protection (ICRP) advises that in principle Diagnostic Reference Levels (DRL) could be used in fluoroscopically guided interventional procedures to avoid unnecessary stochastic radiation risk. The increase in complexity of interventional procedures, combined with a lack of specialist training on radiation techniques, poses a significant risk to patients. These risks have not gone unnoticed by government authorities worldwide and in 2015 the South African Department of Health: Directorate Radiation Control issued requirements to license holders of interventional fluoroscopy units, requiring that a medical physicist optimize their radiation usage using DRLs. The Dose Area Product (DAP) quantity measured for each patient represents a dosimetry index, the value of which for the purpose of improvement should be optimized against the DRL. In this dissertation, I aim to establish if DRLs in the South African private healthcare interventional theatres are high compared to international levels and whether DRLs will optimize the doses used.

Includes bibliographical references / INTRODUCTION: The diagnosis of childhood pulmonary tuberculosis (TB) can be notoriously difficult. The chest X-ray (CXR) is a significant diagnostic resource in the detection of PTB in children. However, non-specific radiological features combined with variable inter-observer assessment s contribute to diagnostic uncertainty. The CXR would be of most value when used specifically to evaluate those features of childhood TB that it shows best and where expert observers agree, namely those signs indicating lymphadenopathy. AIM: To identify simple and reliable CXR features of primary TB in children by determining signs and anatomical sites of best observer agreement. METHOD: This is a retrospective descriptive study within a clinical trial performed by the South African TB Vaccine Initiative (SATVI). Healthy BCG-vaccinated newborn infants in a high TB prevalence rural area in Worcester, near Cape Town, South Africa, were followed for a minimum of two years for possible incident al pulmonary TB. Three independent, blinded, expert paediatric radiologists reported the resultant CXR images using a standardised data collection tick sheet, on which the specific anatomical sites and signs of pathology consistent with pulmonary TB were recorded. The first 200 original data collection tick sheets were sampled and recorded in a pre-compiled data spreadsheet for our study. The sampled data were t hen analysed using kappa statistics. RESULTS: The overall combined agreement for airway compression (by presumed lymphadenopathy) was 0.5%. Five % of the CXR's had soft tissue densities reflecting lymphadenopathy on the frontal view and 5% on the lateral view. The most common site reflecting lymphadenopathy through airway narrowing or displacement was the left main bronchus. The hilar region (kappa 0.27) on the frontal CXR and behind bronchus intermedius (kappa 0.18) on the lateral were the most common sites of soft tissue densities reflecting lymphadenopathy. There were no positive findings for cavitation or pleural effusion. The overall decisions reflecting PTB (lymphadenopathy or miliary) by each individual reader were 27.6% by Reader 1, 8.5% by Reader 2 and 24.6 % by Reader 3. Abnormal findings not specific for PTB were found in 3.5 % by Reader 1, 10.5% by Reader 2 and 3.5% by Reader 3.68. 3 % of the radiographs were reported as normal by Reader 1, 81.9% by Reader 2 and 66.8 % by Reader 3. Only 5% of the radiographs were found to be unreadable by one reader. The overall agreement of all three readers on PTB was 14.6 % and for normal CXR 49.2%. CONCLUSIONS: The fair degree of agreement amongst expert readers suggests that the CXR alone is not a reliable tool for detecting pulmonary TB and should be utilised in conjunction with the clinical features and/or skin tests and blood results. Soft tissue masses rather than airway compression are a more reliable sign for lymphadenopathy, with the most agreed upon sites on the frontal projection for soft tissue mass detection being the right hilar region, followed by the left hilum. Unfortunately, this study could not confirm the usefulness of the CXR in subcategorising PTB into severe and non-severe groups due to the absence of any positive features for severe PTB in the selected sample. The use of prescribed tick-sheets with specified features for detecting lymphadenopathy did not have the expected impact of promoting interobserver consensus of CXR findings in children in terms of detection of TB. The absence of a credible reference standard for lymphadenopathy remains a significant limitation.

Background: Diagnostic imaging forms an integral part of patient evaluation and its use has increased dramatically. Not only is medical imaging a source of increased radiation dose, but also poses other risks such as those related to the procedure performed, the contrast and drugs administered, acoustic and heat deposition and para-magnetic risks. While many studies have assessed doctors' knowledge of radiation risk, data regarding doctors' knowledge of the remaining risks of medical imaging and doctors' attitudes toward consenting practice for imaging is lacking. Aim: To survey and compare the levels of knowledge between referring clinicians and radiologists regarding the risks to patients undergoing medical imaging and to explore doctors' attitudes toward consenting practice. Method: A cross sectional, observational, descriptive study design was employed. The study was conducted using a non-validated, piloted, self-administered three-page questionnaire. The questionnaire was distributed to doctors in various stages of their medical careers at a tertiary level hospital. The questionnaire was constructed in sections including demographics, risks of medical imaging and consent practice. The maximum score potentially attainable was 79, with a point given for each correct answer. No points were given for incorrect, unsure or blank responses. Results: A total of 431 questionnaires were distributed but only 85 doctors (19 radiologists and 66 clinicians) returned a completed survey, yielding a response rate of 19,7%. Older respondents with more years of experience had greater levels of knowledge regarding the risks of medical imaging. There were no significant differences according to gender or university. Although the levels of knowledge of risk was poor overall, radiologists had greater levels of knowledge (mean knowledge score expressed as a percentage =79% compared to that of clinicians= 71%). The largest proportion of doctors' (49%) were of the opinion that clinicians should be responsible for obtaining consent for medical imaging. Only 18% of doctors (radiologists and clinicians) and 5% of clinicians admitted to feeling adequately prepared to obtain consent for medical imaging. Conclusion: We successfully surveyed and compared the levels of knowledge of medical imaging risks amongst doctors and determined their attitudes toward responsibility for consent. The levels of knowledge of the risks of medical imaging is inadequate among radiologists and poor amongst non-radiologists. While statutory body guidelines recommend that the performing health care provider obtain consent, there remains varying opinion as to who should obtain consent. The largest proportion of doctors' were of the opinion that clinicians should obtain consent for medical imaging - this despite clinicians' feelings of inadequacy when consenting patients to the risks of imaging. It is therefore important to take into consideration the levels of knowledge and comfort when making decisions as to who is best suited to obtain consent for medical imaging. With the increased dependence on medical imaging as part of the diagnostic work up, awareness of the risks of medical imaging is of tantamount importance. It is essential to review educational curricula and local policies in order to improve the levels of knowledge of risks of medical imaging amongst healthcare providers, thereby ensuring improved patient safety.

Includes bibliographical references (leaves 44-48). / The primary objective was to undertake a prospective study in order to determine whether abdominal lymphadenopathy detected at ultrasound examination could be used as an indicator of the presence of active extrapulmonary and/or disseminated TB.

Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. Psoriasis is a dermatological condition that affects 1-2% of the population. Approximately 10-15% of patients with skin manifestations of psoriasis develop PsA and 0.3-1% of the general population. Moll and Wright defined PsA as psoriasis associated with inflammatory arthritis and usually a negative serological test for rheumatoid factor (RF).

Includes abstract. / Includes bibliographical references. / BACKGROUND. Penetrating neck trauma is commonly encountered in South African trauma units, and is associated with high mortality and morbidity rates. The imaging protocol for stable patients with penetrating neck trauma remains controversial. There is only sparse data validating the use of Computed Tomography Angiography (CTA) in the evaluation of penetrating neck trauma. OBJECTIVES. To assess the sensitivity and specificity of CTA versus Digital Subtraction Angiography (DSA) in detecting arterial injury and secondarily evaluate the ability of CT to assess non-arterial injury.

Includes bibliographical references. / The aim of this study is to perform a retrospective review of all cases of low-velocity non-missile penetrating orbital trauma with intracranial complications presenting at Groote Schuur Hospital over the 5 year period between 1997 and 2001.

In accordance with consensus of the current literature, we have been using pneumatic reduction by preference at Red Cross Children's Hospital (RCCH) since the early 1990's. The aim of this study is to evaluate the results of our experience since 1989 as we have gradually moved from the hydrostatic method to the pneumatic method. This study will present results of 100 cases seen over a seven year period at the Red Cross Children's Hospital. The results of the respective reduction techniques will be discussed with special attention on complication rates, efficiency and cost implications.

Skeletal muscle structure has been defined on both macro and microscopic levels by gross dissection, light- and electron-microscopy. The basic physiological building blocks involve the electromechanical coupling between interlinking actin and myosin fibres. Detailed intramuscular behaviour during contraction can be clearly defined when examining a single isolated muscle. However, there are few areas in the human body where single muscles act independently to affect motion. This thesis attempts to address the compounded effect that muscles have on each other, while working synergistically in a group, such as the calf muscle.

Study rationale: Diagnosis of pulmonary tuberculosis (PTB) in children relies heavily on chest radiography as sputum samples are difficult to obtain and only yield positive results in 30-74% of children treated for PTB. However, radiological signs between lower respiratory tract infections (LRTI) and PTB overlap considerably and there is a wide inter-observer agreement in the detection of lymphadenopathy, considered the hallmark of PTB. Small pliable paediatric airways are easily compressed by enlarged lymph nodes. Unlike lymph nodes, however, the lucent airways contrast against the surrounding mediastinal structures on radiographs, thus airway compression may serve as a more objective criterion for diagnosing PTB. Many studies have reviewed the radiographic features of PTB in children but few included airway compression or used a control group and none have evaluated inter-observer agreement. Objective: To investigate frequency and inter-observer agreement of airway compression on chest radiographs in children with PTB compared to those with another LRTI. Methods: Chest radiographs of children admitted to Red Cross War Memorial Children’s Hospital with suspected PTB were read by two readers according to a standardised format and a 3rd when there was disagreement. Radiographs of children with definite PTB were compared to those with another LRTI. Frequency and location of airway compression were evaluated. Findings were correlated with human immunodeficiency virus (HIV) infection and age. Inter-observer agreement was assessed using kappa statistic. Results: Radiographs of 505 children (median age 25.9 months [IQR 14.3-62.2]) were reviewed; 97/505 (19%) children were HIV-infected. Airway compression occurred in 54/188 (28.7%) definite PTB cases versus 24/317 (7.6 %) of other LRTI cases (OR 4.9; 95%CI 2.9–8.3). The left main bronchus was most affected in 51/493 (10.3%). A higher frequency of airway compression occurred in infants at 22/101 (21.8%) compared to 56/404 (13.9%) in older children (OR 1.7; 95%CI 1.00–3.00). No association between airway compression and HIV infection was found. Inter-observer agreement ranged from none to fair (kappa of 0.0-0.4). Discussion: The overall frequency of airway compression in definite PTB is compatible with reports in the literature. Although airway compression used alone is not a specific sign, if seen on radiographs, there is a strong correlation with PTB compared to other LRTI with infants at higher risk due to their smaller airways. Contradictory to other studies, our study showed the left main bronchus to be affected twice more commonly than the bronchus intermedius in both age groups. This is thought to be due to different patient selection. Confirming reports in the literature, no significant association between airway compression and HIV status was found. A disappointing finding was the poor inter-observer agreement. Contributing aspects include the lack of standardised criteria in the definition of airway compression and suboptimal visualisation of the airways on standard chest radiographs due to patient, technical and post processing factors. Conclusion: There is a strong association between airway compression on chest radiographs and definite PTB, particularly in infants, irrespective of HIV status. However, its clinical use as an objective criterion in the diagnosis of PTB is limited by poor inter-observer agreement.