Ionising Radiation Regulations Research Articles

An assessment of the radiation dose to patients and staff from a Lunar Expert-XL fan beam densitometer

Dual-energy x-ray absorptiometry (DXA) is a widely used technique for measuring bone mineral density for the identification and management of osteoporotic subjects. The original DXA pencil beam systems expose patients to an effective dose of ionizing radiation of around and require no additional protective shielding for staff. The new fan beam densitometers incorporate solid state detectors and have a higher photon flux, enabling faster acquisition times and giving improved resolution. However, this may be at the expense of higher radiation dose. This study was conducted to assess the radiation dose to patients and staff from the standard scan modes using a Lunar Expert-XL fan beam densitometer. This is, we believe, the first dose assessment of the Expert-XL. The results indicate that the scatter dose at 1 m from the scan table, assuming four AP spine and femoral neck examinations per hour, is about . This is well below the limit of set by the UK's Ionising Radiation Regulations for defining a Controlled Area but above the lesser limit of for a Supervised Area. Typical effective doses to patients are for an AP lumbar spine scan, up to for AP femoral neck, for lateral spine morphometry and for whole body. Although exceeding those of pencil beam DXA machines, these doses are less than for standard radiographic procedures, particularly of the lumbar spine. Where reduced scan time, improved image resolution or morphometric analysis of the spine are required, the patient doses from the Lunar Expert-XL are not prohibitive. Keywords: DXA, dosimetry, fan beam, BMD

Radiation hazards from horses undergoing scintigraphy using technetium-99m.

This paper quantifies the extent of the radiation hazard to personnel from horses undergoing scintigraphy using technetium99m methylene diphosphonate (99Tcm-MDP). From the data produced it is possible to derive safe working protocols which are comfortably within the legislated limits for whole body doses as set out in the Ionising Radiations Regulations 1985. Measurements were made of the surface and environmental activities which result from individuals undergoing scintigraphic evaluation and also from urine contaminated bedding. The use of both high and low activities in the assessment of the radiation hazard to personnel and owners is considered.

Regulation and Inspection Support Radiation Protection in Nuclear and Other Installations

Over the past fifty years, radiation protection legislation in the UK has developed from a narrow industry-specific base to a comprehensive package of regulations and supporting Approved Code of Practice, with additional provisions for nuclear installations. Development of this legislation mirrors progress in international understanding about the risks from exposure to ionising radiation. The current Ionising Radiations Regulations 1985 largely implement the Euratom 1980 Basic Safety Standards Directive and place particular emphasis on the need to keep exposures as low as reasonably practicable. The regulations have been underpinned by the development of the concept of the Tolerability of Risk and the application of the ALARP/ALARA principle, particularly at nuclear installations. Analysis of dose data on HSE's Central Index of Dose Information has shown the general success of this approach in the UK; the data have also allowed targeting of inspection effort. Currently, the Health and Safety Commission and Executive are developing plans for implementing the revised EU Basic Safety Standards Directive.

Commentary: radiation protection supervisors.

The radiation protection supervisor (RPS) is a position required by the Ionising Radiation Regulations of 1985 [1]. This position continues a role which was a requirement of the previous UK regulations prior to European directives.

Fast track hip trial: an evaluation of a change in X‐ray referral

The purpose of this trial was to establish whether a change in the X‐ray referral procedure would reduce the time between presentation and admission for patients who attended a busy Accident and Emergency department with a fractured neck of femur. This group of patients was selected because they are susceptible to decubitus ulcers, the development of which may relate to the time spent on a trolley. Senior nurses in the Accident and Emergency department were educated in patient assessment and management, and knowledge and implementation of ionising radiation regulations. They then referred patients who presented with suspected fractures of the femoral neck to the radiology department within agreed guidelines and without a doctor's examination. Records were kept over a 3‐month trial period. A total of 27 completed cases were recorded and the data included radiological findings, total time from presentation to arrival on the ward or discharge, total time waiting for a porter and being transported, total time spent in the radiology department, and whether the patient reattended for a further X‐ray examination. We concluded that the change in X‐ray referral procedure resulted in an appreciable reduction in the overall time between presentation and admission. However, it was not possible to draw any valid conclusions regarding any reduction in decubitus ulceration as a result of this speedier diagnosis and admission.

An IPSM sponsored intercomparison of dose rate monitoring instrument test results

An intercomparison was arranged to assist participants in assessing their ability to test gamma radiation monitors in order to comply with the requirements of the Ionising Radiations Regulations 1985. This intercomparison used a popular survey meter which had been adjusted to introduce significant errors in its response. The instrument was circulated and the data returned were interpreted to determine whether each participating laboratory had made an accurate measurement of the instrument's response. The results were generally satisfactory but various problems were identified and are discussed.

Safety in the design and use of gamma and electron irradiation facilities: A great britain view

The Health and Safety Executive is the main enforcing authority for health and safety legislation in industrial premises in Great Britain Adequate standards of ionising radiation protection in such workplaces should be achieved by compliance with the Ionising Radiations Regulations 1985 and the associated Approved Code of Practice. The Health and Safety Executive has published guidance on safety in the design and use of gamma and electron irradiation facilities A survey has been undertaken to assess current standards of radiation protection within a sample of industrial irradiation facilities in Great Britain. Compliance with the Regulations and the impact of the new guidance has been assessed. The findings of this survey are described and are being used to develop technical strategies for future inspection and enforcement of the Regulations in such facilities.

Radon—A regional electricity company approach to assessment and control

There are statutory limits on exposure to radon in workplaces in the United Kingdom [Health and Safety, The Ionizing Radiation Regulations, Statutory Instrument 1333. HMSO, London (1985)]. South Western Electricity plc (SWEB) employs approximately 5500 staff within the group in the area which stretches from the Isles of Scilly to Bristol and across into South Wales and Southern England (where it has retail outlets) in parts of which high concentrations of radon can be expected [Radiation doses—maps and magnitudes. NRPB, Didcot (1985)]. The Company's method of assessment and details of a successful remediation scheme installed in a large modern office are described.

Regional Variations in Occupational Exposure to Radon and the Resulting Regulatory Action

Abstract Measurements in over 3000 workplaces throughout Great Britain show that radon concentrations in about 10% of these premises exceed the level at which the Ionising Radiations Regulations 1985 may apply. Most of the measurements and high results are in Cornwall and Devon, but high results have also been obtained in other counties, particularly Derbyshire, Northamptonshire and Somerset. The data for workplaces are supplemented by the results of measurements in about 100,000 homes suitably transposed to indicate the likely impact of the Regulations where workplace data are scarce. These findings have been used to develop advisory and regulatory strategies for workplaces.

Radiation exposure to the hands of orthopaedic surgeons during procedures under fluoroscopic X-ray control

The hands of the surgeon are most likely to be directly exposed to ionizing radiation during fluoroscopic screening in the orthopaedic theatre. There is however little information available on the level of exposure to radiation during the normal working pattern of individual surgeons. The purpose of this study was to directly measure the radiation exposure to the hands during fluoroscopic screening in a series of consecutive cases over a month in order to establish whether these staff need to be designated classified persons, and if not, whether they need to be routinely monitored. Extremity monitoring was carried out using thermoluminescent dosimeters. The dosimeter was secured to the operating surgeon's dominant index finger. 44 procedures were carried out by nine different surgeons. The total radiation dose received per surgeon ranged from 48-2329 microSv. In 80% of procedures the dose of radiation to the surgeon's hand was less than 100 microSv. The extrapolated annual dose, even for the surgeon with the highest radiation exposure, was well below the annual dose limit for extremities of 500 mSv per year recommended by the International Commission on Radiological Protection, and embodied in the Ionizing Radiations Regulations 1985. Despite the relatively low doses of radiation received by surgeons in this study, occupational exposure to all personnel should be kept to the lowest practicable levels, and a review of procedures, including dose measurements, from time to time is advised.

Book review

The Guidance notes which were published in conjunction with the 1985 Ionising Radiations Regulations include a requirement on the total filtration of X-ray beams used for normal diagnostic work. This filtration should not be less than 2.5 mm of aluminium and its measurement forms part of the radiation protection quality system.

BIR Bulletin

The guidance notes for instrument tests which are required under Regulation 24 of IRR85 have been awaited since the appearance of the Ionising Radiations Regulations 1985, which required that instruments used for radiation protection measurements should be tested at intervals not exceeding 14 months, but was not explicit as to what would constitute satisfactory compliance with the Regulations from the point of view of the Health and Safety Executive.

Body aprons in radiation protection

The Guidance Notes associated with the Ionising Radiation Regulations (1985) state that protective aprons for the body shall comply with British Standard 3783 and that they should be examined visually at frequent intervals. This latter clause further states that thorough examination should be carried out at least once a year to ensure that no cracks have developed, and that radiographic examinations are only likely to be justified when the protective material is covered. Uncovered body aprons would seem rarely to be used and it is therefore required of those involved to carry out radiographic, or possibly fluorographic examinations of body aprons at least once a year. It is the carrying out and assessment of such tests which is the subject of this communication.

Occupational Exposure in the National Health Service - The North Western Region

Following the introduction of the Ionising Radiations Regulations 1985, a review of the level of occupational exposure in the NHS in the North Western Region was undertaken to ascertain whether any person needed to be designated as a classified person and to demonstrate compliance with the Regulations concerning non-classified persons working in controlled areas. The initial survey of the 1986 dose data indicated that the level of whole-body occupational dose received by the vast majority of NHS employees was, as expected, extremely low. However, the survey also identified a group of staff involved in brachytherapy who did receive relatively high occupational doses. Operational procedures were reviewed and further dose reduction methods implemented; these, together with the continuing introduction of remotely controlled after loading techniques, has led to a significant reduction in both individual and collective doses in this group and since 1988 no individual have received a whole-body dose exceeding 10 mSv.

Continuing education in radiation protection: assessment of a one-day course

A multiple choice questionnaire was completed by 100 dental surgeons, both at the beginning and at the end of one of several one-day courses on radiation protection. These courses were designed to cover the 'core of knowledge' required by the Ionising Radiation (Protection of Persons Undergoing Medical Examination or Treatment) Regulations 1988. The mean score at the start of each day was 22.86 (out of a maximum possible score of 80), while at the end it was 48.52. The results cast doubt on the belief of the General Dental Council that 'following qualification, dentists will have updated themselves in this area of dental practice'.

Broad-beam transmission data in lead for scattered radiation produced at diagnostic energies

The growth of interventional techniques in radiology and the consequent close proximity of staff to patients during screening emphasizes the need for provision of proper protective clothing and for appropriate personnel monitoring for radiological staff. In order to comply fully with the Ionising Radiation Regulations (HMSO, 1985a) and the associated Approved Code of Practice and Guidance Notes (HMSO, 1985b; HMSO, 1988), an employer must demonstrate not only that staff doses are below any relevant limits but also that they are as low as is reasonably practicable. Since heavy protective aprons may be unduly inconvenient to wear and since routine personnel monitoring makes use of just one or two dosemeters, it is important for both the optimization of protective clothing and the estimation of whole body effective dose equivalent (IPSM, 1977) that the broad beam shielding properties of lead under relevant working conditions are known (Faulkner & Harrison, 1988). Although there are several sources which tabulate the broad beam shielding characteristics of lead and other materials at diagnostic X-ray energies (BSI, 1971; HMSO, 1971; O'Riordan & Brotherton, 1968; Binks, 1943; NCRP, 1976), a number of limitations exist when these data are applied in practice to lead apron shielding: (1) the data represent primary beam attenuation whereas personnel need to be protected against scatter; (2) data for only a limited number of tube voltages are represented possibly leading to difficult interpolation; (3) a very large range of thicknesses is covered by the data and accuracy may be compromised at the low lead equivalent thicknesses of aprons.

Occupational exposure and the Central Index of Dose Information

Occupational exposure to ionizing radiation in the UK is presently controlled by the Ionizing Radiation Regulations, 1985 (Parliament, 1985) which were based on the recommendations of ICRP Publication 26 (ICRP, 1977). These recommendations and, in particular, the dose limits were formulated in the light of contemporary information about the risks of ionizing radiation (UNSCEAR, 1977). Recently, new epidemiological analyses of the survivors of the atomic bombs at Hiroshima and Nagasaki have been published (UNSCEAR, 1988; National Academy of Sciences, 1990). These studies suggest that the risk estimates for low doses and low dose rates may be higher by a factor of about 3 than previous analyses had indicated (Stather et al, 1988). In the light of preliminary announcements of the re-analyses of the atomic bomb survivors (e.g. Preston & Pierce, 1987) and of the ICRP Como Statement (ICRP, 1987), the NRPB recommended that occupational exposure to ionizing radiation should be controlled so as not to exceed an average dose equivalent of 15 mSv per year (NRPB, 1987). This has prompted renewed interest in the levels and distribution of occupational exposure to ionizing radiation. This paper is based on a talk to the meeting organized by the British Institute of Radiology in December 1989 to discuss the implications of the new risk estimates. It presents statistics on occupational exposures in the UK in recent years and discusses the role of the Central Index of Dose Information (CIDI).

Improve your image — 2: Ionising Radiations Regulations, 1985

Improve your image — 2: Ionising Radiations Regulations, 1985

Staff radiation doses associated with nuclear medicine procedures - a review of some recent measurements

Despite publication of the Approved Code of Practice and the Notes for Guidance, implementation of the UK Ionising Radiation Regulations has required local interpretation by nuclear medicine departments. One problem has been the lack of data upon which decisions can be based. In the last five years we and others have made a number of measurements of radiation doses to staff relating to nuclear medicine practice. This paper collates, summarizes and comments on this information. Where possible, results have been expressed in relation to the workload of an average nuclear medicine department.

An analysis of personnel dose records which justifies the application of cost-benefit analysis techniques in the design of an afterloading facility and the use of controlled areas and systems of work within suite to control occupational exposure

The sealed source operational policies employed at the Bristol Radiotherapy and Oncology Centre were originally designed to meet the requirements of the 1972 Code of Practice by ensuring that individual personnel doses were kept below the relevant quarterly and annual dose limits. In 1982-1983, measures were taken to improve personnel radiation safety within the brachytherapy treatment facility by (a) making preparations for the introduction of Selectron medium-dose-rate (MDR) afterloading systems at the centre for intracavitary brachytherapy and (b) reviewing the operational policies to ensure that they meet the more stringent requirements of the ALARA (as low as reasonably achievable) principle, a principle subsequently embodied in the 1985 UK ionising Radiations Regulations (IRR 85). When considering the implications of making existing single-bedded side wards, originally designed for low-dose-rate brachytherapy and suitable for the new systems, the cost of the extra protection required to reduce the instantaneous dose rate in the ward corridors adjacent to the treatment room to less than 7.5 microSv h-1 had to be determined. On the basis of the cost-benefit analysis, it was decided not to provide additional shielding but rather to introduce administrative controls based on local rules which contained systems of work and the operational policies for the afterloading systems. After using the MDR afterloading systems for 2 years, a period in which there has also been a marked increase in interstitial brachytherapy, an analysis was made of the doses received by nursing staff over the past 8 years. This has shown that, in spite of higher dose rates in the corridor areas because of the use of an MDR system and the increase in interstitial techniques, the doses to ward nurses have been significantly reduced by encouraging staff to comply with the ALARA principle and the introduction of afterloading systems.