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.

A Holistic Approach to Assessment of Population Exposure to Radiation: Challenges and Initiatives of a Regulatory Authority.

A regulatory authority for radiation safety should continuously evaluate and improve the national safety framework, in line with current requirements and standards. In this context, the Greek Atomic Energy Commission initiated a series of concerted actions. The radiation dose to the population due to public and medical exposures was assessed. The assessment of dose due to public exposure was based on measurements of radon concentrations in dwellings, radionuclide concentrations in environmental samples, and air dose rates; the assessment of dose due to medical exposure was based on dose measurements for typical examinations or procedures and data on their frequency. The mean effective dose to a member of the population was found to be 4.5 mSv (1.8 mSv and 2.7 mSv from medical and public exposures, respectively). Regarding occupational exposure, aircrew dose assessment, eye lens monitoring, and the national dose registry were significantly improved. With respect to artificial tanning (sun beds), the ultraviolet radiation produced was assessed and the practices followed were observed. Results demonstrated exceedance of the 0.3 W m erythema effective irradiance limit set in European Union standards by 63.5% of the sun beds measured, along with general noncompliance with standards. An overarching activity was the upgrade of the Greek Atomic Energy Commission information system in order to collect and disseminate radiation data electronically, launch a networking strategy for interaction with stakeholders, and facilitate the process of regulatory control. In response to the above findings, regulatory actions have been initiated.

Efficiency of radiation protection equipment in interventional radiology: a systematic Monte Carlo study of eye lens and whole body doses.

Monte Carlo calculations were used to investigate the efficiency of radiation protection equipment in reducing eye and whole body doses during fluoroscopically guided interventional procedures. Eye lens doses were determined considering different models of eyewear with various shapes, sizes and lead thickness. The origin of scattered radiation reaching the eyes was also assessed to explain the variation in the protection efficiency of the different eyewear models with exposure conditions. The work also investigates the variation of eye and whole body doses with ceiling-suspended shields of various shapes and positioning. For all simulations, a broad spectrum of configurations typical for most interventional procedures was considered. Calculations showed that 'wrap around' glasses are the most efficient eyewear models reducing, on average, the dose by 74% and 21% for the left and right eyes respectively. The air gap between the glasses and the eyes was found to be the primary source of scattered radiation reaching the eyes. The ceiling-suspended screens were more efficient when positioned close to the patient's skin and to the x-ray field. With the use of such shields, the Hp(10) values recorded at the collar, chest and waist level and the Hp(3) values for both eyes were reduced on average by 47%, 37%, 20% and 56% respectively. Finally, simulations proved that beam quality and lead thickness have little influence on eye dose while beam projection, the position and head orientation of the operator as well as the distance between the image detector and the patient are key parameters affecting eye and whole body doses.

Radiation exposure of the operator during cardiac catheter ablation procedures.

Radiation exposure of the operator during cardiac catheter ablation procedures was assessed for an experienced cardiologist adopting various measures of radiation protection and utilised electroanatomic navigation. Chip thermoluminescent dosemeters were placed at the eyes, chest, wrists and legs of the operator. The ranges of fluoroscopy time and air kerma area product values associated with cardiac ablation procedures were wide (6.3-48.3 min and 1.7-80.3 Gy cm(2), respectively). The measured median radiation doses per procedure for each monitored position were 23.6 and 21.3 µSv to the left and right wrists, respectively, 25.3 and 30.4 µSv to the left and right legs, respectively. The doses to the eyes were below the minimum detectable dose of 9 µSv. The estimated median effective dose was 22.5 µSv. Considering the actual workload of the operator, the calculated annual doses to the hands, legs and eyes, as well as the annual effective dose, were all below the corresponding limits. The findings of this study indicate that cardiac ablation procedures performed at a modern laboratory do not impose a high radiation hazard to the operator when radiation protection measures are routinely adopted.

Monte Carlo calculations on extremity and eye lens dosimetry for medical staff at interventional radiology procedures.

There are many factors that can influence the extremity and eye lens doses of the medical staff during interventional radiology and cardiology procedures. Numerical simulations can play an important role in evaluating extremity and eye lens doses in correlation with many different parameters. In the present study, the first results of the ORAMED (Optimisation of Radiation protection of MEDical staff) simulation campaign are presented. The parameters investigated for their influence on eye lens, hand, wrist and leg doses are: tube voltage, filtration, beam projection, field size and irradiated part of the patient's body. The tube voltage ranged from 60 to 110 kV(p), filtration from 3 to 6 mm Al and from 0 to 0.9 mm Cu. For all projections, the results showed that doses received by the operator decreased with increasing tube voltage and filtration. The magnitude of the influence of the tube voltage and the filtration on the doses depends on the beam projection and the irradiated part of the patient's body. Finally, the influence of the field size is significant in decreasing the doses.

Doses to operators during interventional radiology procedures: focus on eye lens and extremity dosimetry.

The present study is focused on the personnel doses during several types of interventional radiology procedures. Apart from the use of the official whole body dosemeters (thermoluminescence dosemeter type), measurements were performed to the extremities and the eyes using thermoluminescent loose pellets. The mean doses per kerma area product were calculated for the monitored anatomic regions and for the most frequent types of procedures. Higher dose values were measured during therapeutic procedures, especially embolisations. The maximum recorded doses during a single procedure were 1.8 mSv to the finger (nephrostomy), 2.1 mSv to the wrist (liver chemoembolisation), 0.6 mSv to the leg (brain embolisation) and 2.4 mSv to the eye (brain embolisation). The annual doses estimated for the operator with the highest workload according to the measurements and the system's log book were 90.4 mSv to the finger, 107.9 mSv to the wrist, 21.6 mSv to the leg and 49.3 mSv to the eye. Finally, the effect of the beam angulation (i.e. projection) and shielding equipment on the personnel doses was evaluated. The measurements were performed within the framework of the ORAMED (Optimization of RAdiation Protection for MEDical staff) project.

Active personal dosemeters in interventional radiology: tests in laboratory conditions and in hospitals.

The work package 3 of the ORAMED project, Collaborative Project (2008-11) supported by the European Commission within its seventh Framework Programme, is focused on the optimisation of the use of active personal dosemeters (APDs) in interventional radiology and cardiology (IR/IC). Indeed, a lack of appropriate APD devices is identified for these specific fields. Few devices can detect low-energy X rays (20-100 keV), and none of them are specifically designed for working in pulsed radiation fields. The work presented in this paper consists in studying the behaviour of some selected APDs deemed suitable for application in IR/IC. For this purpose, measurements under laboratory conditions, both with continuous and pulsed X-ray beams, and tests in real conditions on site in different European hospitals were performed. This study highlights the limitations of APDs for this application and the need of improving the APD technology so as to fulfil all needs in the IR/IC field.

Occupational radiation doses to the extremities and the eyes in interventional radiology and cardiology procedures.

OBJECTIVES: The aim of this study was to determine occupational dose levels in interventional radiology and cardiology procedures. METHODS: The study covered a sample of 25 procedures and monitored occupational dose for all laboratory personnel. Each individual wore eight thermoluminescent dosemeters next to the eyes, wrists, fingers and legs during each procedure. Radiation protection shields used in each procedure were recorded. RESULTS: The highest doses per procedure were recorded for interventionists at the left wrist (average 485 µSv, maximum 5239 µSv) and left finger (average 324 µSv, maximum 2877 µSv), whereas lower doses were recorded for the legs (average 124 µSv, maximum 1959 µSv) and the eyes (average 64 µSv, maximum 1129 µSv). Doses to the assisting nurses during the intervention were considerably lower; the highest doses were recorded at the wrists (average 26 µSv, maximum 41 µSv) and legs (average 18 µSv, maximum 22 µSv), whereas doses to the eyes were minimal (average 4 µSv, maximum 16 µSv). Occupational doses normalised to kerma area product (KAP) ranged from 11.9 to 117.3 µSv/1000 cGy cm² and KAP was poorly correlated to the interventionists' extremity doses. CONCLUSION: Calculation of the dose burden for interventionists considering the actual number of procedures performed annually revealed that dose limits for the extremities and the lenses of the eyes were not exceeded. However, there are cases in which high doses have been recorded and this can lead to exceeding the dose limits when bad practices are followed and the radiation protection tools are not properly used.

Extremity and eye lens doses in interventional radiology and cardiology procedures: first results of the ORAMED project.

The main objective of WP1 of the ORAMED (Optimization of RAdiation protection for MEDical staff) project is to obtain a set of standardised data on extremity and eye lens doses for staff in interventional radiology (IR) and cardiology (IC) and to optimise staff protection. A coordinated measurement program in different hospitals in Europe will help towards this direction. This study aims at analysing the first results of the measurement campaign performed in IR and IC procedures in 34 European hospitals. The highest doses were found for pacemakers, renal angioplasties and embolisations. Left finger and wrist seem to receive the highest extremity doses, while the highest eye lens doses are measured during embolisations. Finally, it was concluded that it is difficult to find a general correlation between kerma area product and extremity or eye lens doses.