The ASN currently has little data for assessment of the use of ionising radiation for medical purposes, other than that regarding worker exposure (exposure of patients was described in paragraph 1.5).

According to the data collected by the IRSN in 2004 (IRSN report on worker radiation protection, 2004 summary), about 135,000 people working with medical uses of ionising radiation - or 53% of the total number of monitored exposed workers, covering all activity sectors - were subject to dosimetric exposure monitoring. Medical radiology covers about 69% of the medical personnel exposed. In total, nearly 99% of the persons monitored in 2004 and working in medicine or dentistry received an annual effective dose of less than 1 mSv while 34 overshoots of the annual limit of 20 mSv were recorded (46 in 2003). These overshoots can be broken down as follows: 28 in medical radiology, 3 in radiotherapy, 2 in dental radiology and 1 in occupational medicine. Inquiries are systematically carried out by the occupational medicine services in order to identify the origin of these individual cases.

In 2005, the IRSN's centralised system for collection and analysis of dosimetric data (SISERI) was launched. With the increasingly widespread use of operational dosimetry in the medical field, these tools will give a more detailed picture of exposure, better identify the origin of any cases of the regulatory limits being exceeded and highlight any abnormal situations more quickly.

Except in special circumstances, there is no specific surveillance of the impact of medical applications on the environment and the population. The available information concerns general surveillance of the environment carried out by the IRSN, in particular measurement of ambient gamma radiation, and overall no significant exposure level above the background radiation variations has been highlighted. However, checks on rivers or sewage plants in large towns occasionally reveal the presence above the measurement thresholds of artificial radionuclides used in nuclear medicine (iodine 131, technetium 99m). The available data on the impact of these discharges show that they are estimated at a few microsieverts per year for the most exposed persons (sewerage network staff) and that these radionuclides have never been measured in water intended for human consumption. However, so that more precise data is available on the impact of these releases, and at the request of the ASN, the IRSN is carrying out studies to determine the exposure of certain professional categories working in waste water treatment (sewerage network staff, treatment plant operators, etc.).

In the case of patients who have undergone a nuclear medicine test or treatment, the 21 January 2004 order requires that nuclear practitioners provide their patients with relevant information to limit exposure of persons in contact with them. Now, it is up to the nuclear practitioners and their representative bodies to draft a guide including all the recommendations to be given to the patients. Regular distribution of this information will help limit unnecessary exposure of those in the patient's entourage.

Apart from these measures related to nuclear medicine procedures, the gradual development of the ASN's radiation protection controls, allied with environmental monitoring targeted on certain installations and the use of appropriate computer models, should provide a clearer view of the impact of medical uses of sources of ionising radiation. These actions are part of multi-year programmes.

With the hindsight offered by several years of monitoring of medical installations and contacts with professionals in the medical and dental sectors, as well as the suppliers, installers and inspection organisations, the ASN has now sufficient information to assess the perception of radiation protection by professionals using sources of ionising radiation for medical purposes. The considerable diversity of the installations and medical practices means that radiation protection is dealt with in widely differing ways. The ASN encounters many kinds of situations, ranging from purely administrative radiation protection with the main purpose of declaring the use of a radiology installation or obtaining a licence, to the implementation within an establishment of a structured organisation in order to heighten the awareness and make all those concerned by the use of sources more responsible.

In addition, the radiation protection approach varies considerably depending on whether the ionising radiation is used for its therapeutic and functional imaging effects (dose or level administered) or simply to obtain radiological images.

In the first case, corresponding to the fields of radiotherapy or nuclear medicine, overall the radiation protection rules are known and accepted, provided that they do not constitute an obstacle to the development of medical practices and the performance of medical procedures. However, actual implementation of these rules may often be delayed by administrative, financial or technical constraints specific to hospitals.

In the second case, many users of radiodiagnosis appliances - although this number is now beginning to fall - still see radiation protection as a constraint imposed from outside, with consequences of an administrative (regulatory pressure), technical (obligation to make various installation or work procedure modifications) and financial (cost of modifications, checks, time required, etc.) nature that are felt to be excessive given the fact that the risks are not clearly quantified. Therefore this situation leads to delays in applying current radiation protection regulations.

However, this situation can be offset by information programmes and the work being done by various learned societies and professional bodies which, through high levels of sustained investment, are regularly helping to raise the awareness of those concerned by radiation protection.

These findings should therefore encourage the ASN to continue its efforts to develop supervision of application of the regulations as well as its training and information programmes with the professionals in the medical world, to ensure a continuous process of radiation protection improvement.

In August 2005, the ASN therefore published a letter intended for nuclear medicine professionals, recalling the current radiation protection regulations, together with recommendations designed to make them easier to implement. This document, which is added to that intended for radiotherapists (see point 4.3.1 of this chapter), is a response to a request from the Société française de médecine nucléaire et d’imagerie moléculaire (SFMNIM). It is available from the ASN's website (www.asn.gouv.fr).

To allow a more precise assessment of changes with respect to radiation protection of personnel, installations and patients, the ASN also defined a series of specific indicators.

These indicators will be collected as of 2006 during each inspection of medical or industrial installations conducted by the ASN. A summary of these data will be produced following the annual inspection programme and will be published. Table no. 5 below details the indicators selected, with the corresponding objectives.