Justification of Imaging Medical Exposures: A Review of Literature to Guide Evidence-Based Practice in Zambia

Background: The use of radiation in imaging has increased and resulted in major improvements in the diagnosis of diseases and injuries in medicine. Although the associated risks to patients exposed to radiation are low, the increase in demand is becoming a global concern due to unjustified imaging medical exposures. Objective: To review the literature on the causes of unnecessary medical exposures and strategies used to support referring medical practitioners in the justification of imaging examinations in order to guide evidence-based practice in Zambia. Methodology: Literature search was conducted in PubMed/MEDLINE database to find research, guidelines, expert opinions and reviews. This was supplemented by searching of radiology professional bodies and radiation protection websites. Nine publications were selected based on their relevance and included in this review. Results: Ten main causes of unjustified imaging medical exposures were identified: a lack of awareness about radiation doses and risks, a lack of referral guidelines, over-reliance on imaging, self-referral, defensive medicine, a lack of consultation, non-availability of non-ionising radiation modalities, requesting wrong investigations, repeating examinations which have already been performed, and failing to provide clinical information. Furthermore, three strategies to support medical practitioners were identified: education and training, referral guidelines, and clinical audits. Conclusion: This review has highlighted the main causes of unjustified medical exposures and has brought about awareness of this subject. Even with the resource constraints, it is possible to adopt these strategies identified in this review to support medical practitioners in the justification of imaging medical exposures in Zambia.


INTRODUCTION
The use of radiation in imaging examinations plays a major role in the diagnosis and treatment of diseases and injuries. However, a substantial percentage of imaging examinations using ionising radiation lacks justification, thereby unnecessarily putting patients at increased risk of the biological effects such as 1,2 carcinogenesis. There are three principles of radiation protection: justification, optimisation, and 1,2,3 limitation. However, the focus of this review is on the justification principle. The justification of 3 medical exposures operates at three levels. At the first level, there is a general acknowledgement that the use of radiation in medicine is accepted as doing 1,3 more good than harm. At the second level, a specific imaging examination with a specific 3,4 objective is defined and justified. The main aim at this level is to judge whether the imaging examination will improve diagnosis or provide necessary management for the benefit of the 1,3,4 exposed patient. At the third level, the application of the imaging examination to an individual patient 1,3 must be justified. Even if benefits outweigh risks, there is an unnecessary use of imaging examinations which utilises ionising radiation such as plain film radiography, fluoroscopy, computed tomography (CT), mammography and nuclear medicine (NM), when clinical examination or non-ionising imaging, such as ultrasonography (US) and magnetic resonance imaging (MRI) could provide an accurate In Zambia, there are three groups of medical practitioners who refer patients for imaging examinations: medical doctors, medical licentiate officers and clinical officers. Under the Ionising Radiation Protection Act of 2011 of Zambia, referring medical practitioners have a responsibility 5 to justify each imaging medical exposure. The justification process involves a clinical examination of the patient before making an imaging request, c o n s i d e r a t i o n o f n o n -i o n i s i n g i m a g i n g examinations, and completion of all relevant information on the imaging request form. The completion of clinical details on the imaging request form allows imaging professionals such as radiography technologists, radiographers, or radiologists to confirm the justification of the requested medical exposure. The imaging request form is a "request" and not an "order"; imaging professionals have a responsibility to decline or modify any unjustified imaging examination.
In recent years, the demand for imaging services has increased globally. The available data from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) indicates that between 2000 and 2008, the estimated total number of medical imaging examinations rose from 1.9 6 billion to 3.1 billion globally. According to the Ministry of Health, Zambia is also experiencing an 7 increase in demand for imaging examinations. This increase in demand and the provision for more imaging examinations have resulted in higher 1,2 population exposure to radiation. However, there is a global public health concern because approximately 30% of these imaging medical exposures are unjustified or unnecessary in the 1,4 management of patients. Unnecessary imaging examinations also result in the misuse of healthcare resources, an increase in workload for health professionals, and delays in performing beneficial 1 justified imaging examinations.
The aim of this article is, therefore, to review the literature on the causes of unnecessary medical exposures and strategies used to support referring medical practitioners in the justification of imaging examinations in order to guide evidence-based practice in Zambia.

METHODOLOGY
A l i t e r a t u r e s e a r c h w a s c o n d u c t e d i n PubMed/MEDLINE database in January 2020, using the key words: "justification of medical exposures OR imaging examinations OR radiological examinations". This search was supplemented by a manual search and involved searching the radiology professional bodies and radiation protection websites such as the International Atomic Energy Agency (IAEA), Royal College of Radiologists (RCR), International Commission on Radiation Protection (ICRP) and Radiation Protection Authority of Zambia (RPAZ). Guidelines, opinions, reviews, and research studies were all considered, with no time limit. Articles not published in English language were excluded due to a lack of resources for translation.

RESULTS
Nine publications were found to be relevant and included in this review. These publications were from the UK (N=4), Austria (N=2), Luxembourg (N=2) and United Arab Emirates (N=1). No publication on this subject was found in Zambia. Besides, no causes of unnecessary medical exposures and strategies for supporting referring medical practitioners in the justification process were found in the Ionising Radiation Protection Act 5 of 2011 of Zambia.

Causes of Unjustified Imaging Medical Exposures
There were three publications identified and included in this review on the causes of unjustified medical exposures and their characteristics are presented in Table 1.

Strategies Used to Support Referring Medical Practitioners in the Justification of Imaging Medical Exposures
There were six publications identified and included in this review regarding the strategies used to support medical practitioners in the justification of medical exposures. Table 2 shows their characteristics.

Causes of Unjustified Imaging Medical Exposures
Ten main causes of unjustified imaging medical exposures were identified in this review. These include a lack of awareness about radiation doses and associated risks, a lack of referral imaging guidelines, over-reliance on imaging, self-referrals, defensive medicine, a lack of consultation, nonavailability of non-ionising radiation modalities, requesting wrong investigations, repeating examinations which have already been performed, and failing to provide clinical information (Table 1).
A lack of awareness about radiation doses and associated risks amongst referring medical practitioners is the frequently cited reason for 4,9 unjustified imaging medical exposures. Literature shows that most final year medical students and medical practitioners do not have appropriate awareness about radiation doses for routine imaging examinations utilising ionising radiation and the 14,15,16,17,18 associated biological effects. In simple terms, radiation doses in medical imaging can be sorted into three groups: low, medium and high. Dual-energy X-ray absorptiometry (DEXA) and mammography are low dose imaging examinations; plain film radiography is a medium dose imaging examination and high dose imaging examinations include CT and fluoroscopy.
This review identified the non-availability of referral imaging guidelines as one of the causes of 4 unnecessary medical exposures. The Royal College of Radiologists (RCR), define referral imaging guidelines as evidence-based tools that can guide referring medical practitioners to request the best, safest, and most valuable medical imaging 9 examination. However, there are no referral imaging guidelines in Zambia.
Another cause of unjustified imaging medical exposure identified in this review is non-availability 4 or limited non-ionising radiation modalities. Ultrasonography (US) and MRI are non-ionising radiation imaging modalities that use sound waves 12,19 and magnet fields respectively.
These two modalities are safe and do not give a radiation dose to patients. In Zambia, there are several ultrasound machines and the service is available across the country. However, there are only 5 MRI scanners with the services only available in the Lusaka and Copperbelt provinces. For patients requiring MRI, this limited service can result in using alternative ionising radiation imaging examinations and thereby causing unnecessary medical exposures.
Over-reliance on medical imaging is another cause of unjustified imaging medical exposures identified 4 in this review. Over-reliance on medical imaging may happen when the referring medical practitioner 4 has low confidence in clinical diagnoses. The low confidence in clinical diagnosis results in overdependence on medical imaging examinations and the diagnostic report from the radiologist or reporting radiographer for clinical decisions regarding the patient's management.
Another reason for unjustified imaging medical 4,8 exposures is self-imaging referrals. This is a practice where patients demand imaging examinations. It should be stated that an imaging examination should only be initiated after a medical doctor or other healthcare professional registered to refer patients for imaging examinations performs a 4,8 clinical examination of a patient. This means that self-imaging referral patients should first be clinically examined and only sent for appropriate imaging if deemed necessary by the referring medical practitioner, and the opposite is true. Selfreferrals are a challenge in private practice since they have come into the business.
Defensive medicine is another cause of unnecessary imaging medical exposures identified in this 4,8 review. This is sometimes called defensive medical decision making. It refers to the practice of medical practitioners requesting imaging examinations that 4,8 are not necessarily the best option for the patient. This practice is generally thought to stem from medical practitioners' perception that they can be easily sued by patients or their relatives who seek 20 compensation for presumed medical errors. In other words, defensive medicine is a practice of considering malpractice liability when making decisions regarding the management of a patient.
Other causes of unjustified imaging medical exposures are investigating too early, requesting and undertaking wrong investigations and over- 9 investigating. Some diseases take a long time to manifest radiographically and referring a patient for imaging too early will lead to normal findings but 9,21 cause unnecessary imaging medical exposure. Requesting a wrong imaging examination also 9,21 causes unjustified medical exposures. It is vital to consult an appropriate imaging professional, or senior medical practitioner when in doubt about the appropriate imaging examination to request in a given patient condition or problem. The other cause of unjustified imaging medical exposures is over- 9 investigating. This means undertaking many imaging examinations, some of which may not be necessary.
Repeating imaging examinations that have already been done is another reason for unnecessary 9 irradiation of patients. It is important to attempt to retrieve previous images and diagnostic reports when possible to avoid repeating examinations which have already been performed relatively 9 recently. Most medical facilities in Zambia are still using film-screen combination imaging system. Medical practitioners may face challenges in retrieving unfiled radiographs or access to images undertaken in other medical facilities. During the consultation process, some patients may also not inform medical practitioners of similar imaging 9 examinations undertaken in the past. The a v a i l a b i l i t y o f P i c t u r e A r c h i v i n g a n d Communication System (PACS) which provides digital storage of radiographic images could help in overcoming this challenge. The PACS system could also link several hospitals for easy access and retrieval of images from multiple locations. In Zambia, there is no national PACS system to link public medical facilities offering imaging services.
Another reason for unjustified imaging medical exposures is a failure by referring medical practitioners to provide appropriate clinical 9 information on the imaging request form. Clinical information on the imaging request form assists imaging professionals in evaluating the justification 21 of the examination. It also helps imaging professionals to use a correct imaging technique. This means that a failure to provide clinical details of the patient may result in the use of a wrong technique not beneficial to the patient, for example, the omission of an essential radiographic 9 projection. This can result in the repetition of the imaging examination and exposing the patient to additional ionising radiation.
The other cause of unnecessary imaging medical exposures identified is a lack of communication or consultation between referring medical 4,8 practitioners and imaging professionals. The International Atomic Energy Agency (IAEA) state that in the absence of imaging referral guidelines, referring medical practitioners should consult appropriate imaging professionals if in doubt about the best imaging examination to request for a 21 specific patient condition or problem. Imaging professionals should also consult or clarify with the referring medical practitioners where possible if something is not right for the requested imaging examination. This prevents requesting and performing a wrong imaging examination and exposing a patient to unnecessary ionising radiation.

Strategies Used to Support Referring Medical Practitioners in the Justification of Imaging Medical Exposures
Three strategies to support referring medical practitioners in the justification of imaging medical exposures were identified in this literature review: education and training in radiation protection, development and use of imaging referral guidelines and conducting periodical clinical audits of the justification process ( Table 2).
The first strategy of supporting medical practitioners in the justification process identified in this review is the inclusion of radiation protection in 2,13 the medical curriculum.
The education and training in radiation protection should include all the basic radiation protection knowledge needed by medical doctors and other health professionals who 2 2 refer patients for imaging examinations. Unfortunately, research studies conducted in Africa on this subject have revealed the non-inclusion of 15,16,17,18 radiation protection in medical curriculums. According to European Commission (EC) guidelines on education and training in radiation protection for medical exposures, the main training topics should be on general aspects of patient protection such as biological effects, justification of medical exposures, risk-benefit analysis and typical 22 doses per imaging examination. The basic training should be supplemented with continuing professional development (CPD) learning activities to keep medical practitioners update in their 13 knowledge and skills in this area. In Zambia, there is no radiation protection in the medical 16 curriculum. The strategy of including radiation protection in the curriculum could be adopted in Zambia to support medical doctors, medical licentiate officers and clinical officers in the justification process.
The development and use of referral imaging guidelines is the second strategy of supporting medical practitioners in the justification of imaging 2,10,13,14 medical exposures identified in this review.
The guidelines provide referring medical practitioners with clinical and diagnostic problems, a list of some possible medical imaging examinations applicable to the problem, levels of radiation doses for each type of the imaging examination, recommendations on whether or not the imaging examination is appropriate, and explanatory notes on each suggested imaging 9,10 modality. There is evidence that the use of imaging referral guidelines helps to reduce unnecessary irradiation of patients. For example, randomised controlled trials conducted in the UK on the use of imaging referral guidelines revealed a reduction in 23,24 the number of requests for imaging examinations. Nowadays, imaging referral guidelines are widely used in European countries, United States of 9,10,25,26 America (USA), Australia and New Zealand. To support medical practitioners in Zambia, national referral imaging guidelines could be developed based on the local resources and diseases as recommended by the World Health Organization 1 (WHO). The justification tool could be monitored for its use by conducting periodical clinical audits in each medical facility offering imaging services.
The third strategy for supporting medical practitioners in the justification process identified in this review is the establishment of clinical audits of 2,11,12,13,14 the justification process.
Once imaging referral guidelines are in place, clinical audits could be used for monitoring the use of and compliance 13 with the justification tool. Rawlins and Hine define clinical audit as a quality improvement process that seeks to improve patient care and outcomes through a systematic review of the care provided against the 27 standard. According to the International Atomic Energy Agency (IAEA), clinical audit of the justification process should review the use of imaging referral guidelines, adequacy of imaging 2 requests and repeated imaging examinations. In clinical auditing, unjustified imaging processes are identified and suggestions for improvement are 1,13,27 made.
For example, Bouëtté and others, conducted an audit to evaluate the appropriateness of 28 CT imaging examinations in Luxembourg. The audit found non-compliance to referral imaging guidelines and an awareness programme for medical practitioners was recommended as correction action for improvement. In Zambia, there is a lack of clinical audits related to medical imaging. The strategy of auditing the justification process could be adopted in the Zambian healthcare system. The Zambia Medical Association of Zambia (ZMA) could develop guidelines and Radiation Protection Officers (RPO) in each hospital could conduct clinical audits to improve the quality of imaging referrals.

CONCLUSION
This review has revealed that the inclusion of radiation protection in medical curriculum, the use of referral imaging guidelines and conducting audits of the justification process have been shown to reduce unnecessary medical exposures. Even with the resource constraints, it is possible to adopt these strategies identified in this review in Zambia to support medical doctors, clinical licentiate officers and clinical officers in the justification of imaging medical exposures. It is essential to involve the three stakeholders: Zambia Medical Association (ZMA), Clinical Officer Association of Zambia (COAZ) and Radiological Society of Zambia (RSZ), during the planning and implementation stages. The identified support strategies could be incorporated in the Ionising Radiation Protection Act of 2011 of Zambia [5] to ensure compliance amongst the end-users.