L González

Eye lens exposure to radiation in interventional suites: caution is warranted.

PURPOSE To report estimated radiation doses to the eye lens of the interventionalist from procedures performed with and without use of radiation protection measures. MATERIALS AND METHODS Scattered radiation doses for seven interventional radiology fluoroscopic systems were measured by using phantoms simulating patients 16-28 cm in thickness undergoing low-, medium-, and high-mode fluoroscopy, cine cardiac imaging, and digital subtraction angiography (DSA). The radiation doses to the eye lens in low- and high-dose scenarios were estimated. Beam angulation, biplanar equipment, working distance, procedure complexity, imaging collimation, and use of eyeglasses and/or protective suspended screens were taken into account. The doses to the lens in several procedures were assessed. RESULTS Mean scattered radiation doses to the lens during fluoroscopy were 6.0 and 34.5 microSv/min in the low- and high-dose scenarios, respectively. For DSA, typical doses to the lens ranged from 0.77 to 3.33 microSv per image. Operation modes involving increasing or decreasing radiation doses were quantified. For hepatic chemoembolization, iliac angioplasty, pelvic embolization, and transjugular intrahepatic portosystemic shunt creation, lens doses ranged from 0.25 to 3.72 mSv per procedure when protection was not used. Lens doses in the neuroembolization procedures could exceed 10 mSv per procedure. CONCLUSION With typical reported workloads, radiation doses to eye lenses may exceed the threshold for deterministic effects (ie, lens opacities or cataracts) after several years of work if radiation protection tools are not used.

Patient dose values in interventional radiology

Large exposures incurred in interventional radiology procedures make it advisable to establish reference dose values. These dose values should be quoted in quantities representative of the radiological risk to the patient. In Spain, measurement methods were developed to comply with the European Directive on Patient Protection. Dose-area product and, when feasible, surface dose using thermoluminescent dosimetry chips were measured. Both approaches are discussed, as well as their potential use in patient protection programmes. Initial results are presented for a sample of 680 patients in 10 hospital centres in Spain. Mean, median and range are reported for some specific procedures. Mean values of 8750, 6651, 6663, 9292 and 6816 cGy cm2 are reported for percutaneous transluminal coronary angioplasty, coronary angiography, low extremity, renal and cerebral arteriographies, respectively.

Measurement of radiation doses in the most frequent simple examinations in paediatric radiology and its dependence on patient age

Radiation doses to patients were measured in four X-ray rooms specifically devoted to paediatric radiology, from two hospitals. The study was performed for the most frequent simple examinations, namely abdomen, hip and pelvis, skull, spine and chest. Patients were classed into four different age groups: 0.1-1 year, greater than 1-5 years, greater than 5-10 years and greater than 10-14 years. Operating X-ray generator parameters and entrance surface doses were recorded for all groups. Representative values were obtained for standard working conditions prior to any correcting action being taken. Dose values are reported, and some of the differences between the results found in the rooms for each examination are discussed. Without attempting to relate adult and paediatric radiology, the entrance surface doses measured and the provisionally recommended CEC values for similar examinations in adult patients are compared.

SCATTER AND STAFF DOSE LEVELS IN PAEDIATRIC INTERVENTIONAL CARDIOLOGY: A MULTICENTRE STUDY

Interventional cardiology procedures usually imply high doses to the staff, as paediatric cardiologists need to stay closer to the patient than during adult procedures. Also, biplane systems are used that imply an additional source of staff doses. The objective of this paper is to measure scatter doses in four X-ray systems, using polymethyl methacrylate phantoms with thicknesses ranging from 4 to 16 cm to simulate paediatric patients, for the different acquisition modes. Scatter dose rates measured at the position of cardiologists eyes ranged from 0.8 to 12 mSv h(-1), and about twice the above values at lower extremities, as a linear function of the surface air kerma at the phantom, keeping the irradiated area constant. Therefore, the respective personal dose equivalent for the lens of the eyes may be around 0.5 and 1 mSv throughout the procedure, if additional protection is not used. Simultaneous cine acquisition in biplane systems yielded scatter doses to cardiologists, increased by factors from 5 to 21, compared with a single C-arm acquisition case and depending on geometry. Knowledge of scatter doses for different operation modes, patient thicknesses and the biplane operation should help paediatric cardiologists to adopt conservative attitudes in respect of their occupational radiation risks.

Radiation doses to paediatric patients undergoing micturating cystourethrography examinations and potential reduction by radiation protection optimization

Dose-area product values were measured in paediatric micturating cystourethrography examinations in two dedicated facilities. The results are compared, taking into account features of the X-ray rooms and differences in examination protocol. Several optimization procedures were simulated or implemented, in order to estimate the dose savings which could be attained. Potential savings identified in the dose-area values reach about 85% for both centres.

Image quality and dose in lumbar spine examinations: results of a 5 year quality control programme following the European quality criteria trial.

The large dose values found for lumbar spine examinations in a centre participating in the European quality criteria trial have been investigated within a 5 year quality control programme. Actions focused mainly on optimizing the focus-to-film distance, tube potential (kV), film optical density and X-ray beam filtration. These actions lead to overall dose reductions of up to 75% in lumbo-sacral joint examinations and prove the need for a regular survey of patient skin doses.

Influence of the antiscatter grid on dose and image quality in pediatric interventional cardiology X-ray systems.

To present a methodology and experimental results to assess the influence, in terms of dose and image quality, of the antiscatter grid (AG) in a pediatric cardiology X‐ray system.

Dose–area product values in frequently performed complex paediatric radiology examinations

Mean values of the dose-area product for barium meal, micturating cystourethrography and intravenous urography examinations from three health centres and for four age groups are presented in this study. Values measured are between 13% and 86% higher than results previously reported, which justifies the importance of applying procedures which reduce risks to patients.

Some indicative parameters on diagnostic radiology in Spain: first dose estimations

The Medical Physics Group at the Complutense University of Madrid has been co-ordinating, for approximately 1 year, a project on optimization of radiation protection in diagnostic radiology, in co-operation with the other states of the European Community. Exhaustive data on the subject, which offer accurate results on patient dosimetry for the different types of examination, are the final aim of the project. So far, it has been possible to analyse in detail the data from the National Institute of Health (NIH), which manages the care of about 96% of the Spanish population, plus the findings from several hospitals, outpatient centres and private clinics of the community of Madrid, which allowed us to perform the first dose estimations and to extrapolate them to the rest of Spain. The following estimations are presented: annual frequency of different examinations, their variation from 1985 to 1986, number of diagnostic rooms used for a given minimum of annual examinations, organ doses for different examinations, effective dose-equivalent, genetically significant dose for some examinations, as well as the collective dose.

Evolution of diagnostic radiology in a big hospital during a 5 year period, and the derived collective dose

An analysis is presented of the trends in the annual number of radiological examinations and in the average effective dose equivalent for each type of examination in a big Spanish hospital. Annual frequencies for each type of examination, annual average effective dose equivalent values for each study group, and the contribution of each examination group to the collective dose are presented. Also, sex and age distributions for several important examinations are given, and their impact on the collective dose is reviewed.