Track, calculate and optimise eye lens doses of interventional cardiologists using mEyeDose and mEyeDose_X.

The European epidemiological study EURALOC aimed to establish a dose response relationship for low dose radiation induced eye lens opacities using interventional cardiologists as the study group. Within the EURALOC project, two dosimetry methodologies were developed serving as the basis for cumulative eye lens dose assessment. Besides being the cornerstone of the epidemiological part of the project, these dosimetry methodologies were also used to develop two calculation tools, 'mEyeDose' and 'mEyeDose_X' which enable to track, calculate, optimise and analyse eye lens doses in interventional cardiology. mEyeDose was developed as a Mobile Web App and serves as a readily accessible, highly didactic educational tool for interventional cardiologists whereas the user-friendly desktop application mEyeDose_X is designed for radiation protection professionals. Both tools are freely available and can be used for a wide range of purposes such as optimisation of working practices, calculation of cumulative eye lens doses or risk assessment prior to routine eye lens dose monitoring.

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.

ENERGY AND ANGULAR DEPENDENCE OF RADIOPHOTOLUMINESCENT GLASS DOSEMETERS FOR EYE LENS DOSIMETRY.

Recent studies demonstrated that lens opacities can occur at lower radiation doses than previously accepted. In view of these studies, the International Commission of Radiological Protection recommended in 2011 to reduce the eye lens dose limit from 150 mSv/y to 20 mSv/y. This implies in the need of monitoring doses received by the eye lenses. In this study, small rod radiophotoluminescent glass dosemeters (GD-300 series; AGC, Japan) were characterized in terms of their energy (ISO 4037 X-rays narrow spectrum series, S-Cs and S-Co) and angular dependence (0  up to 90 degrees, with 2 ISO energies: N-60 and S-Cs). All acquisitions were performed at SCK•CEN-Belgium, using the ORAMED proposed cylindrical phantom. For selected energies (N-60, N-80, N-100, N-120 and N-250), the response of dosemeters irradiated on the ISO water slab phantom, at the Ruder Boskovic Institute-Croatia, was compared to those irradiated on the cylindrical phantom. GD-300 series showed good energy dependence, relative to S-Cs, on the cylindrical phantom. From 0 up to 45 degrees, the dosemeters showed no significant angular dependence, regardless whether they were tested when placed vertically or horizontally on the cylindrical phantom. However, at higher angles, some angular dependence was observed, mainly when the dosemeters were irradiated with low-energy photons (N-60). Results showed that GD-300 series have good properties related to Hp(3), although some improvements may be necessary.

Mapping very low level occupational exposure in medical imaging: a useful tool in risk communication and decision making.

OBJECTIVES: The use of ionising radiation in medical imaging is accompanied with occupational exposure which should be limited by optimised room design and safety instructions. These measures can however not prevent that workers are exposed to instantaneous dose rates, e.g. the residual exposure through shielding or the exposure of discharged nuclear medicine patients. The latter elements are often questioned by workers and detailed assessment should give more information about the impact on the individual radiation dose. METHODS: Cumulated radiation exposure was measured in a university hospital during a period of 6 months by means of thermoluminescent dosimeters. Radiation exposure was measured at background locations and at locations where enhanced exposure levels are expected but where the impact on the individual exposure is unclear. RESULTS: The results show a normal distribution of the cumulated background radiation level. No enhanced cumulated radiation exposure which significantly differs from this background level could be found during the operation of intra-oral apparatus, during ultrasonography procedures among nuclear medicine patients and at operator consoles of most CT-rooms. CONCLUSIONS: This 6 months survey offers useful information about occupational low level exposure in medical imaging and the findings can be useful in both risk communication and decision making.

Dealing with pregnancy in radiology: a thin line between science, social and regulatory aspects.

The participation of pregnant women in radiology can be an emotional experience. The word "radiation" understandably invokes fear and uncertainty. Irradiation of a foetus should be avoided whenever possible. However, radiological examinations of pregnant women are often justified and unintended exposures do occur. Also pregnant radiology staff may remain working in the department. Lack of knowledge about the effects of both ionising (X-rays) and non-ionising (MRI) radiation is responsible for anxiety of patients and workers. If foetal exposures occur, they must be quantitatively evaluated and the risk put into perspective. This paper is intended to inform radiology managers, radiologists, technologists and referring clinicians in their management with pregnant patients and co-workers. The paper describes conceptus doses for both patient and worker that are associated with radiology practice, reviews the risks and effects of in utero irradiation, and discusses current national policies, international guidelines and practical aspects.

Personal dose monitoring in hospitals: global assessment, critical applications and future needs.

It is known that medical applications using ionising radiation are wide spread and still increasing. Physicians, technicians, nurses and others constitute the largest group of workers occupationally exposed to man-made sources of radiation. Many hospital workers are consequently subjected to routine monitoring of professional radiation exposures. in the university hospital, UZ Brussel, 600 out of 4000 staff members are daily monitored for external radiation exposures. The most obvious applications of ionising radiation are diagnostic radiology, diagnostic or therapeutic use of radionuclides in nuclear medicine and external radiation therapy or brachytherapy in radiotherapy departments. Other important applications also include various procedures in interventional radiology (IR), in vitro biomedical research and radiopharmaceutical production around cyclotrons. Besides the fact that many of the staff members, involved in these applications, are not measurably exposed, detailed studies were carried out at workplaces where routine dose monitoring encounters difficulties and for some applications where relatively high occupational exposures can be found. most of the studies are concentrated around nuclear medicine applications and IR. They contain assessments of both effective dose and doses at different parts of the body. The results contribute to better characterisation of the different workplaces in a way that critical applications can be identified. Moreover, conclusions point out future needs for practical routine dose monitoring and optimisation of radiation protection.

The use of extremity dosemeters in a hospital environment.

A general overview is given on the use of extremity dosemeters, their calibration, the units and phantoms to be used. One of the major applications of extremity dosemeters is to monitor the personnel in a hospital environment. In nuclear medicine, brachytherapy and interventional radiology (IR) skin doses to hands and legs can be substantial. Here, we report on two studies that are presently being undertaken in Belgium. The first one tries to map the dose distribution on the hands, in function of the manipulation in nuclear medicine. Some preliminary results are also given from a nationwide survey study for patient and personnel doses during IR and cardiology. The radiologists' hands, legs and forehead are monitored during a whole range of procedures in different hospitals.

Health screening with CT: prospective assessment of radiation dose and associated detriment.

The use of computed tomography (CT) for screening of targeted diseases is gaining much interest in the international medical community. An important aspect in the justification of screening with such a high dose examination is the radiation dose to the patient. The objective of this study was to perform a prospective assessment of the radiation dose and associated risk for deleterious effects from a CT screening programme. The excess lifetime risk of fatal cancer for various screening strategies was quantified by estimating the effective dose and by using age dependent mortality risk factors. The accrued data shows that the excess mortality risk due to screening with CT could be substantial. It ranges from 0.01% up to a few percent, strongly depending on the type and method of screening. Consequently, radiation dose and associate risk should be included as fundamental parameters for outlining and deciding a screening approach with CT. Recent technical developments, such as tube current modulation, are promising tools for dose reduction within the constraint of desired image quality.