Occupational dose reduction in cardiac catheterisation laboratory: a randomised trial using a shield drape placed on the patient

What are useful methods to reduce occupational radiation exposure among radiological medical workers, especially for interventional radiology personnel?

Protection against occupational radiation exposure in clinical settings is important. This paper clarifies the present status of medical occupational exposure protection and possible additional safety measures. Radiation injuries, such as cataracts, have been reported in physicians and staff who perform interventional radiology (IVR), thus, it is important that they use shielding devices (e.g., lead glasses and ceiling-suspended shields). Currently, there is no single perfect radiation shield; combinations of radiation shields are required. Radiological medical workers must be appropriately educated in terms of reducing radiation exposure among both patients and staff. They also need to be aware of the various methods available for estimating/reducing patient dose and occupational exposure. When the optimizing the dose to the patient, such as eliminating a patient dose that is higher than necessary, is applied, exposure of radiological medical workers also decreases without any loss of diagnostic benefit. Thus, decreasing the patient dose also reduces occupational exposure. We propose a novel four-point policy for protecting medical staff from radiation: patient dose Optimization, Distance, Shielding, and Time (pdO-DST). Patient dose optimization means that the patient never receives a higher dose than is necessary, which also reduces the dose received by the staff. The patient dose must be optimized: shielding is critical, but it is only one component of protection from radiation used in medical procedures. Here, we review the radiation protection/reduction basics for radiological medical workers, especially for IVR staff.

Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room: An Instant Operator Risk Chart for Daily Practice

Introduction:

While the operator radiation dose rates are correlated to patient radiation dose rates, discrepancies may exist in the effect size of each individual radiation dose predictors. An operator dose rate prediction model was developed, compared with the patient dose rate prediction model, and converted to an instant operator risk chart.

Materials and Methods:

The radiation dose rates (DR_operator for the operator and DR_patient for the patient) from 12,865 abdomen X-ray acquisitions were selected from 50 unique patients undergoing standard or complex endovascular aortic repair (EVAR) in the hybrid operating room with a fixed C-arm. The radiation dose rates were analyzed using a log-linear multivariable mixed model (with the patient as the random effect) and incorporated varying (patient and C-arm) radiation dose predictors combined with the vascular access site. The operator dose rate models were used to predict the expected radiation exposure duration until an operator may be at risk to reach the 20 mSv year dose limit. The dose rate prediction models were translated into an instant operator radiation risk chart.

Results:

In the multivariate patient and operator fluoroscopy dose rate models, lower DR_operator than DR_patient effect size was found for radiation protocol (2.06 for patient vs 1.4 for operator changing from low to medium protocol) and C-arm angulation. Comparable effect sizes for both DR_operator and DR_patient were found for body mass index (1.25 for patient and 1.27 for the operator) and irradiated field. A higher effect size for the DR_operator than DR_patient was found for C-arm rotation (1.24 for the patient vs 1.69 for the operator) and exchanging from femoral access site to brachial access (1.05 for patient vs 2.5 for the operator). Operators may reach their yearly 20 mSv year dose limit after 941 minutes from the femoral access vs 358 minutes of digital subtraction angiography radiation from the brachial access.

Conclusion:

The operator dose rates were correlated to patient dose rate; however, C-arm angulation and changing from femoral to brachial vascular access site may disproportionally increase the operator radiation risk compared with the patient radiation risk. An instant risk chart may improve operator dose awareness during EVAR.