Radiographic Image Recording Techniques When Using Computed Radiography Imaging Systems In The Eastern Cape Province

Abstract

Introduction Computed Radiography (CR) is currently the main leading digital radiography system that was introduced to interchange from conventional film-screen radiography systems. The key advantage of CR over film-screen radiography is the ability to perform postprocessing, which allows image recording faults to be rectified. This, inevitably leads one to inquire whether or not the required radiographic techniques are still being employed prior to post-processing when CR systems are used. Aim of the study The aim of this study was to assess and possibly enhance image recording techniques employed when using computed radiography imaging systems in private and government hospitals in the Eastern Cape province, South Africa. Methodology A retrospective study design, using a self-designed checklist, was utilised to assess the image recording techniques used by diagnostic radiographers when producing CR images. The checklist consists of quantitative data with qualitative elements. Images of the chest and abdomen were evaluated by the researcher and two other assessors. The team assessed a total of 720 (PA/AP and LAT) chest and (erect and supine) abdominal images individually, which were copied from the CR workstations for each assessor. The data were categorically captured by the researcher and analysed by the quality assurance (QA) radiographer to ensure accuracy before sending the hard and soft copies of the sample to the statistician. Thus, the data were also provided to the statistician to verify the accuracy of the checklist results copied into an Excel spreadsheet, through the use of a data theme analyses technique. The technique that was used in the analysis was that of key-words-in-context. Descriptive data, namely frequencies and percentages, were calculated for categorical data. Means and standard deviations or medians and percentiles were calculated from the numerical data obtained. Results Image recording techniques assessed with a consistently high level of accuracy were ‘part selection on CR workstations’, ‘gridline artefact’ exclusion and ‘CR scanner malfunction’, which resulted in averages exceeding 95%. The results also indicated that an unacceptably high number of chest and abdominal examinations that were assessed had averages of non-optimal positioning: [chest (41%) and (abdomen 41%)], non-anatomical markers: [chest (73%) and abdomen (59%)], and no collimation applied: [chest (64%) and abdomen (72%)]. The most noticeable assessments relating to artefacts were foreign objects on the patients manifesting in PA/AP chest (14%), LAT chest (20%), erect abdominal (23%) and supine abdomen (13%) images. Radiographers measure their processed images through EI values, which were assessed as either ‘over exposed’, ‘under exposed’ or ‘in range’. The EI results indicated that the majority of PA/AP chest was ‘in range’ (43%), whereas LAT chest was ‘under exposed’ (45%). Conversely, the abdominal images only showed underexposure as an average of 15% (18% for erect and 11% for supine abdominal images). It is striking to note that overexposure occurred in 52% of the abdominal images compared to 15% overexposure in chest images. Observed with assessment, histogram errors occurred in 7% LAT chest to 5% PA/AP chest, whereas erect and supine abdominal images had equivalent average histogram errors of 3% (n=16) each. Looking at the image quality assessment of all chest and abdominal images, satisfactory results relating to distortion, noise level and the degree of sharpness occurred. However, the study did identify that contrast and density technique image quality falling below an acceptable ‘3’ qualifier value could be improved in both chest and abdominal images assessed. Conclusion and recommendations All research questions and objectives of the study were addressed. This enabled the researcher to conclude that the three key areas requiring attention were: (i) radiographic practice, (ii) setting the exposure and (iii) avoiding artefacts through practical techniques. Recommendations are made to address these findings. Four sections, namely functional, technical, practical, and quality assurance recommendations are proposed.