Does radiology require informed consent for radiation risk?

Abstract

Recent trends in medical decision-making have moved from paternalistic doctor-patient relations to shared decision-making. Informed consent is fundamental to this process and to ensuring patients’ ongoing trust in the health-care profession. It cannot be assumed that patients consent to the risk associated with medical exposures, unless they have been provided with the information to make that decision. This position is supported by both the legal and ethical framework around Radiation Protection detailed in this commentary.

Introduction

Recent trends in medical decision-making have been towards shared patient–doctor decisions. The move to shared-decision making has led to the ethos that patients should be provided with the information necessary to participate in decisions regarding the treatment they wish to undertake. Within radiology, this has led to an increased emphasis on communication of risk for radiation exposures and increased exploration of what is ethically and legally required.¹ In the UK, the requirement to provide information to the patient has been enshrined in law.² The requirement is that the employer produces a procedure for:

‘providing that wherever practicable, and prior to an exposure taking place, the individual to be exposed or their representative is provided with adequate information relating to the benefits and risks associated with the radiation dose from the exposure;’

Often discussions around whether patients should be informed of the risk are conflated with the practical issues around carrying out the process. The aim of this commentary is to separate out and further examine the legal, moral and ethical imperatives to provide information around radiation risks to patients prior to exposure in the UK. A necessary next stage is to identify and address the barriers to carrying out this process; however, this is beyond the scope of the current commentary.

Ethical argument

The ethical foundations for Radiation Protection have been considered and described in ICRP Report 138.³ The core values set down were:

• Dignity

• Prudence

• Justice

• Beneficence/non-maleficence

These values should be central to decision-making around the safe use of radiation. For example, although there is some uncertainty as to the exact level of risk at low radiation doses, a prudent and pragmatic approach is to use the Linear No Threshold (LNT) model.⁴ Equally, a key component to safeguarding the autonomy and dignity⁵ of a patient is to ensure that they are aware of and willingly accept the risk associated with any medical procedure. Although some patients may be aware of this risk, to ensure parity (justice) for all patients it is prudent to provide information to all.

There are some instances where the principle of beneficence/non-maleficence may be used to argue against the provision of information on radiation risk, e.g. if a professional believes that fear of radiation could lead to aversion to low levels of risk that are justified. However, if a full explanation of the risk has been provided then the patient has to be given agency to follow the course of action that fits with their individual values. A method of resolving such conflicts has been proposed by Task Group 109⁶ and is likely to develop further in the near future.

In addition to these core values, the document details procedural values of accountability, transparency and inclusivity. None of these procedural values are compatible with the withholding of potential risk information from a patient. Therefore, the core ethical values of Radiation Protection are consistent with informing the patient of radiation risk from the outset.

Legal argument

Whilst the Ionising Radiation (Medical Exposure) Regulations 2017² require that the patient is provided with information regarding the risk, the concept of consent is not directly mentioned.

Following a legal precedent set by Montgomery⁷, there is a duty of care on the clinician to discuss all material risks. Material risks are those to which a “reasonable person in the patient’s position would be likely to attach significance…”.

Therefore, if it can be established that a reasonable person would consider the radiation risk significant, then patients should be informed of that risk. There are numerous examples in the literature where patients have expressed the desire to be provided with this information. For example, Youssef et al. (2014)⁸ found that in the emergency department 316/409 (77.3%) of individuals believed that an informed consent form should be signed for CT. Therefore, there is increasing evidence that the majority of patients attach significance to and want to be informed of the risk associated with medical radiation exposures and so consent should be obtained.

Guidance from the Royal College of Radiologists (RCR)⁹ on consent which pre-dates the Montgomery⁷ ruling states that the majority of radiology will involve very low levels of radiation and implied consent will be obtained at the time of the examination. In order to imply consent a patient must first understand the risks.¹⁰ Therefore, implied consent is not applicable where a patient attends for an examination that they do not know could be associated with a risk of cancer. A recent literature review found that there was a general lack of awareness of radiation risks among patients.¹¹ Clearly, attendance of an individual for an X-ray does not imply a knowledge and acceptance of the radiation risk associated with it. The RCR also state that judgement should be used to determine when implied, expressed or written consent are obtained depending on the level of complexity of the procedure and the significance of any risk or side-effects. It is not clear at this point at what level radiation risks represent a significant level of risk.

There are some procedures for which written consent is required, e.g. in interventional radiology procedures. Patients have stated that they expect to be informed of the radiation risk associated with these procedures;⁸ however, in a survey of 29 interventional radiology departments, it was found that 89% did not routinely inform patients of radiation risks.¹² Therefore, even where informed consent is being obtained, this information is still not being provided adequately.

Assuming that consent is required, there are three situations in which this information may not be provided¹³:

• If the information is ‘detrimental to the patient’s health’⁷

• Treatment is urgent but the patient cannot give valid consent.

• The patient declines to receive the information.

It could therefore be stated that the ‘wherever practicable’ clause in IRMER² is designed to cover these situations. The use of the first derogation to argue against providing radiation risk information due to potential radiophobia should carefully consider the potential ethical conflicts previously discussed.

Implications of failure to disclose risk

If informed consent was not obtained and an individual went on to develop cancer in the future, within jurisprudence the individual would have to prove causation to succeed in a negligence claim.¹⁴ This means that there is a duty to show that ‘but for’ the lack of adequate consent the individual would not have developed cancer. Effectively this means:

1. The individual would need to show that if informed they would not have had the exam.

2. By going ahead with the exam they developed cancer as a result.

Due to the high background levels of cancer and the fact that cancer cannot usually be directly attributed to a specific instance of radiation exposure, it would be difficult to prove negligence. Therefore, the legal ramifications of failure to adequately consent may be limited.

However, there is a tort case (McGhee v National Coal Board [1973] 1 WLR 1) in which an individual who cleaned out brick kilns and was not provided with a shower by their employer developed contact dermatitis. Although it could not be definitively proven that the lack of a shower caused the dermatitis, the House of Lords ruled that there was ‘no difference between the material contribution to an injury and the material contribution to the risk of an injury’.¹⁵ If this were applied to the case of cancer developed following radiation exposure, then it is possible that negligence could be shown.

Conclusion

It is proposed that the only stance consistent with both the legal and ethical requirements around Radiation Protection is that informed consent is required for exposure to medical radiation.

Whilst it is not always necessary to obtain written consent, establishment of a consensus on a practical graded approach to consent for Radiology is required. Where written consent is obtained for other reasons (e.g. in interventional radiology) the potential radiation risks should be discussed as part of the consent process.

Barriers to the introduction of informed consent processes must be identified and tackled but cannot be used to argue that informed consent is not necessary. A particular area for future attention is whether patients feel that they should be informed of uncertainty around the LNT model and how this affects processing of information around the risk.