Strategies to Reduce Radiation Exposure in Electrophysiology and Interventional Cardiology Sandeep Shankar, MD, DM, 1 Deepak Padmanabhan, MD, DM, 1 Avinash Chandrashekharaiah, BE 2 and Saurabh Deshpande, MD, DM 1 1. Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India; 2. BMS College of Engineering, Bengaluru, Karnataka, India
Abstract Clinical diagnosis sometimes involves the use of medical instruments that employ ionizing radiation. However, ionizing radiation exposure is a workplace hazard that goes undetected and is detrimental to patients and staff in the catheterization laboratory. Every possible effort should be made to reduce the amount of radiation, including scattered radiation. Implementing radiation dose feedback may have a role in reducing exposure. In medicine, it is important to estimate the potential biologic effects on, and the risk to, an individual. In general, implantation of cardiac resynchronization devices is associated with one of the highest operator exposure doses due to the proximity of the operator to the radiation source. All physicians should work on the principle of as low as reasonably achievable. Methods for reducing radiation exposure must be implemented in the catheterization laboratory. In this article, we review the available tools to lower the radiation exposure dose to the operator during diagnostic, interventional, and electrophysiological cardiac procedures.
Keywords Radiation exposure, electrophysiology, interventional cardiology, ionizing radiation, workplace hazard, cardiac resynchronization devices Disclosure: The authors have no conflicts of interest to declare. Received: 17 July 2019 Accepted: 22 December 2019 Citation: US Cardiology Review 2019;13(2):117–22. DOI: https://doi.org/10.15420/usc.2019.21.2 Correspondence: Deepak Padmanabhan, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bannerghatta Main Rd, Phase 3, Jayanagara 9th Block, Jayanagar, Bengaluru, Karnataka 560069, India. E: firstname.lastname@example.org Open Access: This work is open access under the CC-BY-NC 4.0 License which allows users to copy, redistribute and make derivative works for non-commercial purposes, provided the original work is cited correctly.
Ionizing radiation is a workplace hazard that goes undetected. In the cardiac catheterization laboratory, where various interventional and electrophysiological procedures are done, physicians and other staff are exposed to ionizing radiation daily. The amount of radiation exposure in the catheterization laboratory is exponentially more compared to other departments using X-ray and fluoroscopy, which increases even more in complex cases. Staff are at a higher lifetime risk of various medical conditions, ranging from cataracts to malignancies. The two major sources of radiation exposure to staff in the cardiac catheterization laboratory are scattered X-ray photons and X-ray tube leakage. As per the original definitions given by International Commission on Radiological Protection, radiation effects were classified into stochastic (random) and non-stochastic (or deterministic). Currently, the classification has been changed to stochastic and tissue reactions, but there is an overlap of common reactions, such as thyroid cancer and cataracts, into both types.1 Radiation in the catheterization laboratory is generated using two different modes: fluoroscopy or cine angiography (cine). Fluoroscopy is used for catheter placement and involves 95% of the total X-ray operation time, but only causes 40% of the total radiation exposure to staff and patients.2
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Cine is used to acquire diagnostic images and to generate a permanent record of the procedure, and although representing only 5% of the total X-ray tube operation time, 60% of the total radiation exposure to staff and patients occur during cine. This is primarily due to the use of a relatively high dose required to record onto film. It has been revealed that there may be an excess risk of brain tumors among interventional cardiologists.3,4 The lens of the eye is a region of particular interest, with several studies showing an increased incidence of cataracts among catheterization laboratory staff.5–7 A recent study of radiation-induced cataracts documented that 52% of interventional cardiologists had posterior subcapsular cataracts, citing radiation as the cause.6 The occupational effective dose limit to radiation workers is 20 mSv per year averaged over 5 years, and the dose limit for the eye has recently been reduced from 150 to 20 mSv a year to further protect against the rising number of radiation-induced cataracts.8 Recent evidence suggests that even protracted low-dose radiation exposure could be associated with leukemia, carotid artery atherosclerosis, and early vascular aging.9,10 Physicians need to keep the dose as low as reasonably achievable (ALARA),11 regardless of occupational dose
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US Cardiology Review Volume 13 Issue 2 Winter 2019