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Too Many X-rays - keep taking the guidelines

There is ample evidence that too many patients are being referred for X-ray investigations which produce no clinical benefit. Through being given an unnecessary X-ray dose the patient may actually receive a clinical disbenefit. Purchasers are wasting some of their precious resources on an immediate test when recourse to available professional guidelines on the best use of radiology departments would both save them money and benefit their patients.

Royal College Guidelines

Concerned by the increasing number and cost of diagnostic facilities, the Royal College of Radiologists (RCR) has examined the extent to which the use of these facilities is effective. One early, striking result was in the use of skull radiography in the management of patients with head injury, when it was shown that only one patient in 4,800 might benefit. This led to the setting up in the period 1987-1990 of multi-centre studies of both GP and hospital practice designed to measure the effect of introducing guidelines of good practice for radiography. Each study showed a sharp reduction in X-ray referrals and investigations in the period following the issue of the guidelines: a decrease of 1,615 of the 12,782 referrals (12.6%) in the general practice study, and of 31,400 of the 403,000 inpatient and outpatient investigations (7.8%) in the hospital study.

Large reduction in skull X-rays

Within the overall figures, some particular trends are evident. For example the largest decrease in both GP referrals (30%) and hospital investigations (23%) was in skull X-rays, consistent with the earlier report of the RCR. Other large percentage reductions were noted in spinal and chest X-rays examinations which are the most common of all X-ray procedures. Abdominal referrals changed very little after the issue of the guidelines. This suggests that the guidelines were able to be used in a discriminatory manner to avoid unnecessary X-ray investigations but not at the expense of reducing those that may be beneficial.

20% of X-rays clinically unhelpful

Of particular interest are the values of the largest reductions by single centres that were observed in the study. These varied between about 15% to just under 50% for different types of examination. These levels of reduction are consistent with those observed in other independent studies and led the RCR Working Party to conclude that there is strong evidence that at least 20% of the radiological examinations carried out in NHS hospitals are clinically unhelpful. This translates over the whole country to an annual total of 7 million unnecessary X-ray examinations costing about £60 million, with the highest numbers of unnecessary X-ray examinations being those of chest, limbs and joints, and the greatest financial costs arising from examinations of the chest and from barium investigations.

Reducing X-ray doses to patients

In addition to these direct costs there are also indirect costs that derive from the effect of the X-ray doses to patients from the unnecessary X-ray examinations. The joint working party of the RCR and the National Radiological Protection Board on patient dose reduction estimates that the potential collective patient dose reduction from the limitation of clinically unhelpful X-ray examinations amounts to 3,200 man Sieverts across the whole country. This is roughly equivalent to the annual collective dose produced by all other artificial radiation sources.

Estimates of the monetary valuation of the harm associated with the exposure of 1 man Sievert are £5,000-£10,000, which translates to an annual national cost of £15-30 million with the collective figure given above. Another way of looking at this is the number of additional fatal cancers that could result from the unnecessary X-ray doses. The risk to a patient from a single X-ray examination is of course very small, but available estimates of the lifetime risk of fatal cancers from common types of X-ray examination suggests that something of the order of 100 fatal cancers may arise each year from unnecessary X-ray examinations if the figures given earlier are correct.

There are clearly substantial patient benefits and cost reductions to be achieved from the elimination of unnecessary X-ray examinations, and these benefits lie in the hands of doctors who refer patients for X-ray examination. The guidelines issued initially by the Royal College of Radiologists and subsequently modified and incorporated into locally issued guidelines are the result of wide discussion between hospital clinicians and general practitioners.

The guidelines offer clear guidance in any given clinical situation whether and in what circumstances an X-ray investigation is indicated or not indicated. The earlier RCR studies have shown that guidelines of this kind can reduce substantially the number of unnecessary and unhelpful X-ray examinations with benefits both to patients and purchasers. However the Royal College Working Party was clear that the problems in how to assure compliance with agreed standards of practice have yet to be resolved. It is also likely to be true that without follow-up the initial beneficial effect of the guidelines will diminish. We must try to find ways of getting the message across and to make good practice become standard practice.

Dr CCF Blake, Regional Scientist, A&ORHA


  1. Costs and benefits of skull radiography for head injury. Lancet 1981 ii:791-795.
  2. R Chisholm. Guidelines for radiological investigation. British Medical Journal 1991 303:797-798.
  3. A multicentre audit of hospital referral for radiological investigation. British Medical Journal 1991 303:809-812.
  4. Influence of the Royal College of Radiologists guidelines on hospital practice. British Medical Journal 1992 304:740-743.
  5. Influence of Royal College of Radiologists guidelines on referral from general practitioners. British Medical Journal 1993 306:110-111.

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