Recommendations for the use of active personal dosemeters (APDs) in interventional workplaces in hospitals.

Occupational radiation doses from interventional procedures have the potential to be relatively high. The requirement to optimise these doses encourages the use of electronic or active personal dosimeters (APDs) which are now increasingly used in hospitals. They are typically used in tandem with a routine passive dosimetry monitoring programme, with APDs used for real-time readings, for training purposes and when new imaging technology is introduced. However, there are limitations when using APDs. A survey in hospitals to identify issues related to the use of APDs was recently completed, along with an extensive series of APD tests by the EURADOS Working Group 12 on Dosimetry for Medical Imaging. The aim of this review paper is to summarise the state of the art regarding the use of APDs. We also used the results of our survey and our tests to develop a set of recommendations for the use of APDs in the clinical interventional radiology/cardiology settings, and draw attention to some of the current challenges.

THE USE OF ACTIVE PERSONAL DOSEMETERS IN INTERVENTIONAL WORKPLACES IN HOSPITALS: COMPARISON BETWEEN ACTIVE AND PASSIVE DOSEMETERS WORN SIMULTANEOUSLY BY MEDICAL STAFF.

Medical staff in interventional procedures are among the professionals with the highest occupational doses. Active personal dosemeters (APDs) can help in optimizing the exposure during interventional procedures. However, there can be problems when using APDs during interventional procedures, due to the specific energy and angular distribution of the radiation field and because of the pulsed nature of the radiation. Many parameters like the type of interventional procedure, personal habits and working techniques, protection tools used and X-ray field characteristics influence the occupational exposure and the scattered radiation around the patient. In this paper, we compare the results from three types of APDs with a passive personal dosimetry system while being used in real clinical environment by the interventional staff. The results show that there is a large spread in the ratios of the passive and active devices.

EURADOS 2016 INTERCOMPARISON EXERCISE OF EYE LENS DOSEMETERS.

In the context of a new annual eye lens dose limit for occupational exposure equal to 20 mSv, European Radiation Dosimetry Group (EURADOS) organized an intercomparison dedicated to eye lens dosemeters, including photon and beta radiations. The objective was to complete the first intercomparison recently organized by EURADOS for photons and to update the overview of eye lens dosemeters available in Europe. The dosemeters provided by the 22 participants coming from 12 countries were all composed of thermoluminescent detectors. The dosemeters were irradiated with photon and beta fields defined in relevant standards. The results, provided by participants in terms of Hp(3), were compared to the reference delivered doses. Results are globally satisfactory for photons since 90% of the data are in accordance to the ISO 14146 standard requirements. The respective values for betas stress the fact that dosemeters designed for Hp(0.07) are not suitable to monitor the eye lens dose in case of betas.

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.

Radiation-Induced Lens Opacities among Interventional Cardiologists: Retrospective Assessment of Cumulative Eye Lens Doses.

This study describes the retrospective lens dose calculation methods developed and applied within the European epidemiological study on radiation-induced lens opacities among interventional cardiologists. While one approach focuses on self-reported data regarding working practice in combination with available procedure-specific eye lens dose values, the second approach focuses on the conversion of the individual whole-body dose to eye lens dose. In contrast with usual dose reconstruction methods within an epidemiological study, a protocol is applied resulting in an individual distribution of possible cumulative lens doses for each recruited cardiologist, rather than a single dose estimate. In this way, the uncertainty in the dose estimate (from measurement uncertainty and variability among cardiologists) is represented for each individual. Eye lens dose and whole-body dose measurements have been performed in clinical practice to validate both methods, and it was concluded that both produce acceptable results in the framework of a dose-risk evaluation study. Optimal results were obtained for the dose to the left eye using procedure-specific lens dose data in combination with information collected on working practice. This method has been applied to 421 interventional cardiologists resulting in a median cumulative eye lens dose of 15.1 cSv for the left eye and 11.4 cSv for the right eye. From the individual cumulative eye lens dose distributions obtained for each cardiologist, maxima up to 9-10 Sv were observed, although with low probability. Since whole-body dose values above the lead apron are available for only a small fraction of the cohort and in many cases not for the entire working career, the second method has only been used to benchmark the results from the first approach. This study succeeded in improving the retrospective calculation of cumulative eye lens doses in the framework of radiation-induced risk assessment of lens opacities, but it remains dependent on self-reported information, which is not always reliable for early years. However, the calculation tools developed can also be used to make an assessment of the eye lens dose in current practice.

Effectiveness of pelvic lead blanket to reduce the doses to eye lens and hands of interventional cardiologists and assistant nurses.

The aim of the present study is to analyse quantitatively the potential reduction of doses to the eye lens and the hands of an operator and a nurse by the use of a pelvic lead blanket during coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures. Thermoluminescent dosimeters were used to assess dose levels to the left eye lens and fingers on both hands of both physician and nurses during single procedures performed with or without the lead blanket. The measurements were carried out at one medical centre and include dosimetric data from 100 procedures. Additional measurements including physician's and patient's doses were made on phantoms in the laboratory. In order to determine the reduction potential of the lead blanket, the doses normalized to DAP (Dose-Area Product) corresponding to the same position of dosimeter were compared against each other for both procedure categories (with and without protection). There was no statistically significant decrease observed in physicians' and nurses' eye lens doses, nor in doses normalized to DAP due to the use of the lead pelvic shield in clinic. However, some trend in reducing the eye lens doses by this shield can be observed. Regarding finger doses, the differences are statistically significant but only for physicians. The mean DAP-normalised doses to the eye lens and left and right finger of physicians, in the presence of a ceiling-suspended transparent lead shield, were 2.24e-5 ± 1.41e-5 mSv/µGym2, 2.31e-4 ± 1.21e-4 mSv/µGym2, and 2.60e-5 ± 1.57e-5 mSv/µGym2 for standard procedures performed without the lead blanket, and 1.77e-5 ± 1.17e-5 mSv/µGym2, 1.70e-4 ± 1.01e-4 mSv/µGym2, and 1.86e-5 ± 1.13e-5 mSv/µGym2 for procedures performed with it. A comparison of the results from the laboratory and the clinic shows that they are consistent regarding the eye lens, while for fingers it suggests that the dose reduction properties of the lead shield are related to the physician's work technique and both patient and lead blanket sizes or its positioning. The highest degree of reduction is observed for cranial and caudal projections together with the use of a patient-adjustable lead blanket; about a 2-fold decrease in finger doses is expected for optimum conditions. However, the laboratory measurements suggest that the use of lead blanket might slightly increase the patient dose, but only when specific projections are constantly used. This limitation should be considered by cardiologists during clinical work if this protection is used. In the light of the presented results, the ceiling-suspended transparent lead shield and the lead glasses seem to be the preferred way to reduce the doses to the eye lens, compared to the lead blanket.