Establishing the European diagnostic reference levels for interventional cardiology.

Interventional cardiac procedures may be associated with high patient doses and therefore require special attention to protect the patients from radiation injuries such as skin erythema, cardiovascular tissue reactions or radiation-induced cancer. In this study, patient exposure data is collected from 13 countries (37 clinics and nearly 50 interventional rooms) and for 10 different procedures. Dose data was collected from a total of 14,922 interventional cardiology procedures. Based on these data European diagnostic reference levels (DRL) for air kerma-area product are suggested for coronary angiography (CA, DRL = 35 Gy cm2), percutaneous coronary intervention (PCI, 85 Gy cm2), transcatheter aortic valve implantation (TAVI, 130 Gy cm2), electrophysiological procedures (12 Gy cm2) and pacemaker implantations. Pacemaker implantations were further divided into single-chamber (2.5 Gy cm2) and dual chamber (3.5 Gy cm2) procedures and implantations of cardiac resynchronization therapy pacemaker (18 Gy cm2). Results show that relatively new techniques such as TAVI and treatment of chronic total occlusion (CTO) often produce relatively high doses, and thus emphasises the need for use of an optimization tool such as DRL to assist in reducing patient exposure. The generic DRL presented here facilitate comparison of patient exposure in interventional cardiology.

Main clinical, therapeutic and technical factors related to patient's maximum skin dose in interventional cardiology procedures.

OBJECTIVE: The study aimed to characterise the factors related to the X-ray dose delivered to the patient's skin during interventional cardiology procedures. METHODS: We studied 177 coronary angiographies (CAs) and/or percutaneous transluminal coronary angioplasties (PTCAs) carried out in a French clinic on the same radiography table. The clinical and therapeutic characteristics, and the technical parameters of the procedures, were collected. The dose area product (DAP) and the maximum skin dose (MSD) were measured by an ionisation chamber (Diamentor; Philips, Amsterdam, The Netherlands) and radiosensitive film (Gafchromic; International Specialty Products Advanced Materials Group, Wayne, NJ). Multivariate analyses were used to assess the effects of the factors of interest on dose. RESULTS: The mean MSD and DAP were respectively 389 mGy and 65 Gy cm(-2) for CAs, and 916 mGy and 69 Gy cm(-2) for PTCAs. For 8% of the procedures, the MSD exceeded 2 Gy. Although a linear relationship between the MSD and the DAP was observed for CAs (r=0.93), a simple extrapolation of such a model to PTCAs would lead to an inadequate assessment of the risk, especially for the highest dose values. For PTCAs, the body mass index, the therapeutic complexity, the fluoroscopy time and the number of cine frames were independent explanatory factors of the MSD, whoever the practitioner was. Moreover, the effect of technical factors such as collimation, cinematography settings and X-ray tube orientations on the DAP was shown. CONCLUSION: Optimising the technical options for interventional procedures and training staff on radiation protection might notably reduce the dose and ultimately avoid patient skin lesions.

Results of a European survey on patient doses in paediatric radiology.

Paediatric patients represent a very specific group within the radiology department. Compared to adult patients, they are more sensitive to radiation. As they are sometimes submitted to several radiology procedures, dose and image quality should be well balanced. Nowadays, only a few centres specialize in paediatric imaging, and knowledge of paediatric patient doses is, therefore, very scattered. The effect of the introduction of digital technology on paediatric patient doses remains largely undocumented. Data collected in the present survey illustrate that there is a clear need for standardisation in this domain. The proposal of a European diagnostic reference level (DRL) is quite difficult. Preliminary DRLs, based on typically 5-7 radiology centres per examination are proposed. The 'effective dose' may or may not be a very rigorous parameter, but it still remains useful nowadays to calculate a parameter that summarises the possible radiation-induced detriment to these young patients. However, conversion factors for calculation of the effective dose should be harmonised. Future studies should include an image quality evaluation study, using criteria that account for digital equipment. Data collection would be straightforward and could be performed in a systematic and automatic way if DICOM headers of digital images would include appropriate as well as relevant information for the particular case of paediatric examinations.

Quality criteria for cardiac images: an update.

The DIMOND II and III Cardiology Groups have agreed on quality criteria for cardiac images and developed a scoring system, to provide a tool to test quality of coronary angiograms, which was demonstrated to be of value in clinical practice. In the last years, digital flat panel technology has been introduced in cardiac angiographic systems and the radiological technique may have been influenced by the better performance of these new detectors. This advance in digital imaging, together with the lesson learned from previous studies, warranted the revision of the quality criteria for cardiac angiographic images as formerly defined. DIMOND criteria were reassessed to allow a simpler evaluation of angiograms. Clinical criteria were simplified and separated from technical criteria. Furthermore, the characteristics of an optimised angiographic technique have been outlined.

[Radiation doses received by premature babies in the neonatal intensive care unit]. / Doses d'irradiation reçues par les prématurés en service de réanimation.

PURPOSE: Because of frequent radiological investigations performed in neonatal intensive care unit, a dosimetry study was carried out to assess the level of doses received by premature babies. MATERIALS AND METHODS: In vivo measurements were performed and effective doses were evaluated for single radiographs. Individual cumulative doses received over the period of stay were then estimated, for each premature baby entering the intensive care unit in 2002, taking into account the number of radiographs they underwent. RESULTS: On average, babies stayed for a week and more than one radiograph was taken per day. Results showed that, even if average doses per radiograph were relatively low (25 microSV), cumulative doses strongly depended on the length of stay, and can reach a few mSv. CONCLUSION: Even if doses per radiograph are in agreement with European recommendations, optimisation of doses is particularly important because premature babies are more sensitive to radiation than adults and because they usually undergo further radiological examinations in other services. On the basis of the results of this dosimetry study, the implementation of a larger study is being discussed.

Radiation protection and quality assurance in diagnostic radiology--an IAEA coordinated research project in Asia and eastern Europe.

The International Atomic Energy Agency currently has two parallel Coordinated Research Projects (CRP) running in Asia and Eastern Europe. The main objective of the CRPs is to raise the level of awareness in participating countries about the need for radiation protection for patients undergoing diagnostic radiology procedures. This is to be achieved by first assessing the status quo in a sample of hospitals and X-ray rooms in each participating country. A program of optimization of radiation protection for patients is then introduced by means of a comprehensive quality assurance program and the implementation of appropriate dose reduction methods, taking into account clinical requirements for diagnostically acceptable images. Patient dose assessment and image quality assessment are to be performed both before and after the introduction of the quality assurance program. The CRP is divided into two phases--the first is concerned with conventional radiography, while the second involves fluoroscopy and computed tomography. The CRP is still running, restricting the scope of this paper to a discussion of the approach being taken with the project. The project will be completed in 1998, with analysis to follow.

Evaluation of a new low-dose digital x-ray device: first dosimetric and clinical results in children.

BACKGROUND: A new low-dose digital X-ray device, based on Charpak's Nobel prize-winning multiwire chamber, enables the production of images at very low doses. Objectives. To present the first dosimetric and clinical results. MATERIALS AND METHODS: The analysis was performed on 93 children with scoliosis and 47 undergoing pelvic radiography. The comparative study between conventional X-ray and the new technique focused on three points: (1) the dose delivered by each system (2) the diagnostic information provided by each system and (3) comparison of image quality criteria with European guidelines. RESULTS: The mean ratio of conventional dose to that of the low-dose technique was 13.1 for the spinal examination and 18.8 for the pelvis. There was no significant difference in diagnostic information available from each modality, but there was a slight difference in quality criteria in favour of the conventional technique. CONCLUSION: This new device allows spectacular dose reduction, consistent with adequate clinical information. Improvements of the prototype will lead to extension of potential indications and industrial development.

[Photostimulation plates or conventional films for bedside chest x-ray in pediatric radiology? A comparative study of quality of image and the dose delivered to patients]. / Plaques photostimulables ou films conventionnels pour les clichés pulmonaires "au lit" en radiopédiatrie? Une étude comparative de la qualité de l'image et de la dose délivrée aux patients.

Image quality and patient doses received during chest bedside examinations performed with conventional (film-screen combination) and photostimulable phosphorus plate systems were compared in a study carried out in 1993 in a French pediatric radiology department. Seventy one children (36 males and 35 females) aged between 9 days and 18 years (average: 43 months) were included in the study. Technical performances of all radiological equipment used were permanently checked through a quality control program. One conventional and 3 "photostimulable" films were performed for each patient included (mAs product selected for "photostimulable" system was progressively reduced down to 60% of that of conventional technique). TLD Lithium Fluoride chips were used to measure entrance surface dose during the examination. Image quality of 284 films (213 "photostimulable" + 71 conventional) was assessed by three independent radiologists. Advantages and drawbacks of both studied imaging techniques are discussed in terms of patient dose reduction and image quality.

Quality control in mammography: an initiative in France.

The ultimate effectiveness of any mass screening campaign is directly related to strict compliance with certain rules and technical protocols designed for radiological installations. Concerning radiological screening, the primary technical objective is to ensure reproducibly high quality images at low radiation dose to the patient. This paper describes the methodology followed for the implementation of a quality control (QC) programme of 48 mammography installations used within the context of the breast cancer screening campaign in the Bas-Rhin region of eastern France. In order to demonstrate the efficacy of such a programme, results of QC tests and procedures relating to each element of the radiological imaging chain are presented and compared for four control visits carried out at 6 month intervals over a period of 2 years. A reduction of 50% (from 16 mGy to 7.5 mGy) of breast entrance doses (normalized to a breast thickness of 4.5 cm) and a significant improvement of detectability of high contrast details are discussed. The importance of encouraging an extension of a similar process to the other screening experiments currently underway in France is emphasized.

Evaluation of chemically sensitive patients.

An increasing number of patients have been presenting with multiple symptoms they attribute to low-level chemical exposures, ie, multiple chemical sensitivities (MCS). Although some studies have evaluated such patients, the selection criteria has not been rigorously defined. The present study is the first to use a relatively rigorous definition of MCS to select patients for study. Comprehensive evaluation of medical, psychiatric, neuropsychological, and immunological status of a series of MCS patients is presented. In contrast to previous studies, patients in this study did not have a history of psychiatric disorder. However, some patients were currently depressed. Neuropsychological assessment did not reveal any abnormalities with the exception of one test of verbal memory for which performance was consistently poor relative to the normative sample. No significant immunological abnormalities were noted.

[Evaluation of radiation doses during radiological tests]. / Evaluation des doses délivrées au cours d'examens radiologiques.

The purpose of this document is to provide radiologists with a simple, but realistic means of determining the individual dose delivered to a patient during a radiological examination both in the region under investigation and at any other particularly sensitive organs. Fourteen types of examinations were considered corresponding to those most frequently carried out in France. The choice of examinations and methods of taking the films approaches as closely as possible, the average situations, and the frequency of different techniques is influenced by the results of a national study of radiodiagnostic examinations carried out in France in 1982. In the first section, the influence on the radiation dose of varying different physical parameters and techniques is analysed, with an aim of defining the limits of validity of the presented dosimetric values and the possible adaptation of these values to any individual situation, which is slightly different from these considered in this study. The second section describes the model used for determining the absorbed dose presented in the tables, concerning each type of examination, as well as bibliographic references referring to methods and results of determining the dose. The suggested calculation model may be used as a base for dose estimation for other types of examination.

Caveat emptor: allergic rhinitis.

This case report illustrates that the typical symptoms of allergic rhinitis--rhinorrhea, itchy eyes, nose and throat--should not be taken as a routine phenomenon without consideration of other differential diagnoses. Caveat Emptor: "allergic rhinitis."

Assessment of airway hyperresponsiveness in chronic stable asthma.

Airway reactivity and disease severity were investigated in 24 subjects with stable chronic bronchial asthma. Disease severity was determined by assigning a disease severity score (DSS) representing six clinical and therapeutic parameters. Airway hyperresponsiveness was assessed in two ways: airway reactivity score (ARS) based on the number of positive responses to a question concerning exposure to 22 nonspecific inhaled irritants and methacholine challenge testing and determining the cumulative dose causing a 20% reduction in FEV2 (CMD20). A significant correlation between DDS and CMD20 (r = 0.57; p less than 0.003) and DSS and ARS (r = 0.67; p less than 0.0003) attested to the important influence of airway hyperresponsiveness on disease severity. Significant correlations for ARS with CMD20 (r = -0.60; p less than 0.002) suggested the consistency with which the ARS estimated methacholine hyperresponsiveness. We found no statistically significant correlations between DSS, ARS, or CMD20 and the age of subject, duration of asthma, or other host characteristics. There was not a significant correlation between the degree of airway obstruction and DSS or ARS noted. The results of this investigation demonstrate the value of the use of clinical information for assessing airway hyperresponsiveness and disease severity in patients with chronic stable asthma. Both ARS and DSS are useful clinical tools for estimating methacholine reactivity.

Doses to patients from dental radiology in France.

In France, a national study was undertaken to estimate both dental radiology practices (equipment and activity) and the associated population collective dose. This study was done in two steps: A nationwide survey was conducted on the practitioner categories involved in dental radiology, and dosimetric measurements were performed on patients and on an anthropomorphic phantom by using conventional dental x-ray machines and pantomographic units. A total of 27.5 x 10(6) films were estimated to have been performed in 1984; 6% of them were pantomographic and 94% were conventional. Most of the organ doses measured for one intra-oral film were lower than 1 mGy (100 mrad); pantomogram dose values were generally higher than intra-oral ones. The collective effective dose equivalent figure was 2,000 person-Sv (2 x 10(5) person rem) leading to a per head dose equivalent of 0.037 mSv (3.7 mrem). The study allowed authors to identify ways to reduce the patient dose in France (e.g., implementing the use of long cone devices and controlling darkroom practices).

Doses to patients from diagnostic radiology in France.

Reported here are results of a 1982 national survey in France to establish the collective effective dose equivalent associated with the main types of radiological examinations practiced annually in this country (except nuclear medicine, C.T. scans, dental radiology and mass chest screening). This report describes the methodology followed in achieving dose measurements either on an anthropomorphic phantom or directly on the patient, and it highlights the importance of the radiological procedures (number of x-ray films, fluoroscopy screening time, etc.) on the patient organ doses. The estimated collective effective dose equivalent associated with these radiological practices is 86,000 person-Sv, i.e., an individual effective dose equivalent of 1.58 mSv y-1; the genetically significant dose figure is 0.29 mSv and the collective red bone marrow dose due to 45 million x-ray exams practiced in France (1982) is 40,300 person-Sv, i.e. 0.74 mSv per inhabitant.

A comparison of diagnostic radiology practice and patient exposure in Britain, France and Italy.

Surveys have been conducted in Britain, France and Italy, using essentially the same techniques, to establish the level of provision of diagnostic radiology services, the frequency of X-ray examinations and examples of the radiation doses delivered to patients in each country. Different national strategies for conducting some types of X-ray examination and marked differences in the general availability of this aspect of health care indicate that the justification and optimization of medical exposures is not interpreted in the same way in these countries.

[Collective irradiation caused by radio-diagnostic procedures in France in 1982. Results (2)]. / L'irradiation collective due aux pratiques de radiodiagnostic en France en 1982. Les résultats (2e partie).

This paper gives the most important results of the collective dose received by patients who undergoing diagnostic radiology examinations in France in 1982. It details, per each X-ray examination type, the collective organ dose associated with, and highlights the importance of the radiological procedures (number of X-ray films, fluoroscopy screening time) on the received patient doses. If one takes into account organs for which dosimetric measurements have been carried out, the collective effective dose equivalent per 10(6) inhabitants is 442 man-Sievert; the genetically significant dose reaches 0.295 mSv and finally the collective red bone marrow dose due to 45 million X-ray exams practiced in France (1982) is 40,300 man-Sievert i.e. 0.742 mSv. per inhabitant.

[Collective radiation dosage due to radiodiagnostic practice in France in 1982. Methodology. 1]. / L'irradiation collective due aux pratiques de radiodiagnostic en France en 1982. Méthodologie (1re partie).

This paper recalls the main concepts of dosimetry which are useful when assessing the collective dose to the patient from medical X-ray examinations. It describes the general protocol which has been followed in measuring dose associated to each x-ray exam (anthropomorphic phantom, in vivo measurement) and gives some results about the variations of parameters such as the mAs, the kVp and the fluoroscopy screening time. As far as the gonadal dose and the effective dose equivalent are concerned a first evaluation is given per type of examination carried out in France in 1982.