Radiological protection in medicine

Draft document: Radiological protection in medicine
Submitted by Ian Belton, Regional Medical Physics Department
Commenting as an individual

I am a consultant medical physicist and head of nuclear medicine services in the above department and my comments are written from that perspective. In general these guidelines provide an excellent summary of radiological protection principles and practice in medicine. I would like to make the following specific comments: In section 7 the introduction of new practices is discussed. The comment is made that the radiation risk is viewed as secondary and a process of optimisation is undertaken rather than justification. I would suggest that it is important that any new practice should be justified as well as optimised and I believe this is the situation in the UK. In section 12 it is recommended that access to controlled areas in brachytherapy and nuclear medicine is limited to patient''s visitors following appropriate advice. It would appear that this recommendation is based on access to controled areas for reason of high activity therapy patients. There are often other controlled areas within nuclear medicine departments where access is still, by definition, controlled, but access is allowed to others for tasks such as supporting the patient. In thses circumstances, control is necessary to maintain the principle of ALARP. I would suggest that the recommendation should be more all-encompasing and recognise the variety of situations that may be faced in nuclear medicine. In section 13 DRLs are discussed. For nuclear medicine, only imaging is considered. DRLs are also applicable to nuclear medicine laboratory procedures and this should be recognised. In section 15 it is stated that the ''final responsibility for the radiation exposure lies with the physician who should therefore be aware of the risks and benefits or the procedures involved''. It is not clear to which physician this statement refers, namely the physician referring or the physician responsible for justification. These are normally two different people and I suggest it should be made clear that this responsibility lies with the latter. In sub-section 17.7 the release of patients following therapy with unsealed radionuclides is discussed and a dose limit of 1mSv for infants and children is recommended. There may well be situations, with compelling societal factors where, in rare instances, it would be of benefit for the parent and child for this to be exceeded. I would suggest that this limit should in fact be a dose constraint with the limit being 5mSv in five years (an average, therefore, of 1mSv per annum). This would allow some flexibility whilst ensuring the overall dose is kept to an acceptable level by recognising the fact that several repeat treatments over such a timescale would be exceedingly rare.