The discovery of X-rays and their usefulness in detecting human disease was a significant milestone in the development of modern medicine. For the first time, doctors had a "picture" of what was going on underneath the body's surface. Diagnosis could be made with certainty and disease progression measured.
The magical X-ray was not without side effects, however. Many of the pioneers of radiology, including Marie Curie, paid the ultimate price for repeated exposure. Bone marrow was particularly susceptible to large doses of radiation, with the result that many doctors developed leukaemia and other diseases of blood cells, whose life begins within the bones' soft centre.
Modern X-ray machines are far more focused and controlled than those of yesteryear and do not pose a risk to operators or patients. Nevertheless, there is no known safe level of radiation and in order to maximise the benefits it is important to keep the number of investigations to a minimum. Recent studies have suggested that a 50 per cent reduction in the number of X-rays could be achieved without detriment to the care and treatment of patients.
The European Union has issued a directive on radiation protection (97/43 Euratom) which is scheduled to become law in all EU countries on May 13th. It introduces the concept of "Xray prescribing" for the first time. Articles 3 and 5 of the directive refer to the "justification process" whereby a doctor now must assess the overall benefit to the patient of a referral for an Xray examination. Article 3 specifically states: "A practice involving exposure to radiation should produce sufficient benefit to the exposed individual or to society to offset the detriment that it causes." What will be the effect of the directive in practice? Already within hospitals, the introduction of guidelines and protocols has helped to reduce the number of unhelpful X-rays. In one Limerick hospital, this has resulted in a 30 per cent reduction in X-ray referrals. A key element is the creation of a feedback loop from the X-ray department to the referring doctor. If the radiographer or radiologist feels that the investigation may not be justified they must make contact with the doctor to seek clarification before the examination is performed.
One of the beneficial side effects of new hospital guidelines has been the freeing of extra capacity for use by outpatients. The focus will now be on general practitioners, to make appropriate use of X-rays in the context of the EU directives.
Dr Brian Coffey, chairman of the Irish College of General Practitioners, the body responsible for quality issues in general practice, has said that X-ray guidelines "will become increasingly important in the context of quality patient care". The college has circulated its members with a Royal College of Radiologists (RCR) booklet entitled "Making the best use of a Department of Clinical Radiology".
The introduction to the RCR guidelines contains six questions for doctors to ask themselves before they order an X-ray. In fact, they are questions which patients might also usefully ask their doctors before attending a radiology department.
Six questions on X-rays
1. Do I need this test?
Ask your doctor whether the result of the X-ray will affect your treatment. For example, it is rarely necessary to confirm "wear and tear" changes in the discs of the spine in the older person as these are as normal as grey hairs from early middle age.
2. Do I need the X-ray now?
An example of good timing is the need to repeat a chest X-ray after a bout of pneumonia. It is important to do this, but the timing is the key. If a repeat chest film is ordered before the course of treatment is complete, then the request is probably premature.
3. Have I had this particular test before?
You may have attended an Accident and Emergency Department prior to seeing your regular doctor. It may well be that he wishes to perform some tests which have already been done. Previous X-ray films are usually available on request. Indeed, the electronic transfer of digital data will make this process even simpler in the years ahead.
4. Have I given my doctor all the details?
While the onus is on your doctor to take an adequate history, it is important that you provide him with an unedited and complete description of your symptoms. A more complete story could result in the choice of a different type of investigation.
5. Is this the best investigation for me?
You must rely on your doctor's advice in answering this question; nevertheless it is useful to ask him if there is an alternative. An increased availability of MRI scanning will lessen the demand for CT scans.
6. Are too many tests being suggested?
Some doctors rely on investigations more than others. Some patients take comfort in being investigated. Would it be possible to do less tests, or at least to perform them on a sequential basis?
Finally, it is important to remember that not all requests for X-rays are for diagnostic purposes. Both the mapping (for radiotherapy) and monitoring (post-chemotherapy) of treatment are crucial in looking after a person with cancer. An increased use of X-ray is justified in this situation; the results may prevent uncomfortable or inappropriate treatment being given to the patient.
Messages for Dr Muiris Houston can be left on 01-6707711, ext 8511 or by email: mhouston@irish-times.ie