Optimisation of X-ray examinations: General principles and an Irish perspective

South African radiographers' radiation protection practices, a qualitative study

INTRODUCTION

Radiation protection is multifarious, and consequently, a radiographers' application of radiation protection is multifaceted. Studies have shown varying radiation protection practices among radiographers. The first quantitative phase of this explanatory, sequential mixed-method study used the theory of planned behaviour to explore South African radiographers' radiation protection behaviour. Overall, South African radiographers' attitudes to radiation protection, subjective norm, perceived behavioural control, and radiation protection intention was high. This second phase of the study aimed to explore the reasons for South African radiographers' radiation protection practices.

METHODS

This study used an exploratory and descriptive qualitative approach. Data was collected through 13 in-depth semi-structured telephone interviews. Thematic analysis was used in order to uncover original phenomena. Data saturation was achieved and the study adhered to trustworthiness and ethical measures.

RESULTS

Thematic analysis identified two themes. The participants had the appropriate radiation protection knowledge, but radiation protection compliance remained a personal choice. Impediments such as feeling rushed during imaging of trauma and challenging patients, patients knowledge of radiation protection, resources, imaging referrals, inadequate training when transitioning from analogue to digital radiography and managerial support contributed to radiation protection compliance. Strategies such as further education, research and a change in mindset were suggested to further foster radiation protection compliance.

CONCLUSION

Even though participants' knowledge of radiation protection aligned with the legislated guidelines, limited internalising of the knowledge resulted in compliance being a personal choice. Participants reflected on their insouciant attitude and observed a similar attitude in their radiographer colleagues. Patient and work-related impediments were identified to contribute to radiation protection compliance. Strategies to further foster compliance were suggested.

IMPLICATIONS FOR PRACTICE

Understanding the reasons for radiographers' choice in radiation protection will allow the development of strategies that foster optimum application of radiation protection practises. Developing a radiation protection culture that enhances personal compliance supported by education and evidence should be considered.

Can the anode heel effect be used to optimise radiation dose and image quality for AP pelvis radiography?

INTRODUCTION

A study was conducted to determine whether the anode heel effect can be used to influence optimisation of radiation dose and image quality (IQ) for AP pelvis radiography.

METHODS

ATOM dosimetry phantom and an anthropomorphic phantom were positioned for AP pelvis. Using a CR system, images were acquired and doses were measured with phantom feet toward anode and then feet toward cathode. Exposure factors (kVp, mAs and SID) were systematically generated using a factorial design. Images were scored visually for quality using relative visual grading together with a 3 point Likert scale. Signal to noise ratio was also calculated as a physical measure of image quality. Dosimetry data were collected for the ovaries and testes.

RESULTS

The optimum technique for male, which resulted in lower dose and suitable image quality, was with feet positioned toward the anode (0.80 ± 0.03 mGy; SNR of 38 ± 2.9; visual IQ score 3.13 ± 0.35). The optimum technique for female was with feet toward anode (0.23 ± 0.02 mGy; SNR of 34.7 ± 2.6; visual IQ score 3.15 ± 0.26). kVp had the biggest effect on both visual and physical image quality metrics (p < 0.001) for both tube orientations, whereas SID had the lowest effect on both visual and physical image quality metrics compared with mAs and kVp (p < 0.001). The effect of SID on the SNR was not significant (p > 0.05) with feet toward anode.

CONCLUSION

Positioning the patient with feet toward the anode, as opposed to the cathode, has no adverse effect on visual image quality assessment but it does have an effect on physical image quality.

IMPLICATIONS FOR PRACTICE

This study would add a new clinical concept in positioning of AP pelvis radiography especially for male positioning.

A practical approach to prioritise among optimisation tasks in X-ray imaging: introducing the 4-bit concept

According to European and national legislation, as well as international recommendations, X-ray examinations shall be optimised. However, with limited resources and hundreds of different types of X-ray examinations, it may be difficult to prioritise among the optimisation tasks at a radiology department. This work is focused on describing a method that can be used to determine the order of which the examinations should be optimised. In the Medical Exposure Directive from 1997, the European Commission prescribes the content of an optimisation process in relation to medical exposure. A reasonable interpretation of the directive is that the assurance of medical purpose for a justified examination is superior to the need of decreased radiation dose. This was used as a basis for developing a method for prioritisation among optimisation tasks. For each examination type, the following four yes/no questions are raised: (i) Is the present image quality unacceptable? (ii) Is the examination of particular importance? (iii) Is the radiation dose suspiciously high? (iv) Are there special dose level concerns, e.g. diagnostic reference levels? Arguing that a positive response to any of the four questions results in the examination being higher prioritised than otherwise and that the questions are labelled in order of decreasing relevance, it can be shown that the resulting flow chart, determining the order of which the examinations should be optimised, can be described by a 4-bit binary scale. In this way, each examination type is given a number from 0 to 15, a higher number corresponding to the examination being prioritised higher in the optimisation work. The method was applied to a general radiology department and resulted in a well-discriminated distribution of examinations prioritised for optimisation tasks. In conclusion, taking into account both medical outcome and potential risk, the proposed method can be used to determine the order in which examinations at a radiology department should be optimised.