Editorial

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• Safety perspectives
• References
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Safety perspectives 

This is the third ICRP report in 4 years to address safety in radiotherapy. In so doing, we have covered both general aspects and very specific problems emerging with one particular method.

Making general recommendations concerning protection against harmful effects of radiation is at the core of what the ICRP is all about. Medical radiation is by far the biggest manmade contribution to the average dose, is growing rapidly, and can give relatively or very high doses [in diagnostics, a single whole-body computer tomography (CT) scan gives an effective dose of some 10–20mSv, i.e. of the same order of magnitude as the dose limit for occupational exposure; in radiotherapy, the unwanted side effect of dose to organs outside the target area is often about 10 times higher].

This does not mean, in any way, that such doses are unwarranted. Rapid CT scans to investigate accident trauma have saved many lives, and the same is certainly true of radiotherapy. The collective dose to mankind from medical radiation is more than 1 million man Sv. Basically, it is desirable for this to increase as modern diagnostic and therapeutic procedures are still hopelessly out of reach for many people who would benefit greatly from their application. However, with improved justification and optimisation, some unnecessary or unhelpful exposure of patients could be removed. As pointed out by Fred Mettler, the former chairman of ICRP Committee 3, removing just 1% of the collective dose in medicine would have the same effect as removing all occupational exposure worldwide!

The fact that the ICRP is providing very specific and practically oriented advice on radiological protection in relation to selected methods in medical practice is much appreciated by our users; such advice is not always easily available elsewhere. In fact, the recent spate of topical reports on specific medical radiation problems came about as a result of the responses received when the ICRP asked the medical profession what they perceive as problem areas and how we could help.

Thus, returning to general and specific treatments of radiation safety in radiotherapy, ICRP Publication 86 (2001) dealt with the prevention of accidental exposures of radiotherapy patients. The report was of a general nature and covered many types of therapy and accidents.

One problem area mentioned in Publication 86 concerned accidents with high-dose-rate (HDR) brachytherapy. ICRP Publication 97 (2005b) returned to this topic with a more detailed report and up-to-date information. In the present report, we are addressing an even more specific topic, namely safety in brachytherapy for prostate cancer using permanently implanted sources.

The need for this report is not driven primarily by an accident history. While there have been some unpleasant accidents in HDR brachytherapy, the ICRP is not aware of any accident with the iodine or palladium seeds used for therapy against prostate cancer. However, the technique is spreading rapidly, with more than 50,000 patients/year being treated at the present time; there is a potential for various undesirable scenarios; and the fact that the sources stay permanently implanted in the patient requires consideration of the radiological situation vis-à-vis people in the patient’s vicinity.

The latter includes a broad variety of family members, other members of the public, and staff. This report pays particular attention to the possibility of exposures in connection with cremation of patients who pass away within a few months of treatment. Unless proper precautions are taken, this could lead to undue exposures to the public and crematorium staff.

On a completely different topic, most readers of the present report will be aware that in 2004, the ICRP consulted on the next set of basic Recommendations, intended to replace the 1990 Recommendations of ICRP Publication 60 (1991). The consultation generated more than 600 pages of comments (all of which are visible at our website, www.icrp.org) from some 200 different responders. ICRP Supporting Guidance 4 (2005a) includes a summary of the draft Recommendations that were subject to consultation in 2004 and the papers that led up to those draft Recommendations.

The Recommendations project comprises not just the actual Recommendations but also a series of ‘foundation documents’ and other building blocks underpinning the Recommendations. Some of the comments on the draft Recommendations reflect that those building blocks were not publicly available back in 2004. The ICRP has also concluded that some additional background material will be required on the scope of our Recommendations, on the radiological protection paradigm, and on radiological protection in medical contexts.

The ICRP has now consulted on the draft ‘foundation documents’, texts are being edited to take account of the comments received, and the additional material required is being drafted. These developments have necessitated an amended schedule. We currently envisage another round of consultation in 2006, and hope to achieve approval of the Recommendations towards the end of 2006 (thus illustrating the eternal editorial curse of changes after material was sent to press; Supporting Guidance 4 refers to ‘the draft 2005 Recommendations’).

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References 

1. ICRP, 1991. 1990 Recommendations of the International Commission on Radiological Protection. ICRP Publication 60, Ann. ICRP 21 (1–3).
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2. ICRP, 2001. Prevention of accidental exposures to patients undergoing radiation therapy. ICRP Publication 86, Ann. ICRP 30 (3).
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3. ICRP, 2005a. Development of the Draft 2005 Recommendations of the ICRP: a collection of papers. ICRP Supporting Guidance 4, Ann. ICRP 34 (Suppl).
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4. ICRP, 2005b. Prevention of high-dose-rate brachytherapy accidents. ICRP Publication 97, Ann. ICRP 35 (3).
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