Image guided interventional procedures have become increasingly popular owing to the higher success rate and minimal invasion associated with it. Interventional cardiology teams face high quantum of radiation exposure due to a large number of complex interventional procedures performed in the Cath lab every day. Other fluoroscopy-assisted procedures, like trans-catheter valve replacements, are creating demand for Cath Lab time and skills. Also, the ability to treat cardiovascular, peripheral, and valve disease in a minimally invasive technique is increasing the addressable patient population and provides benefits like short recovery time and lesser complications. However, these procedures expose the interventional team’s long-term health at risk which calls for adequate radiation protection methods during interventional cardiology procedures.
Deterministic risks associated with radiation exposure are well established. Termed as ‘exposure threshold’ for tissue injury, the effect of radiation differs at varying radiation dose range. For instance, exposure to a radiation dose of about ≈2 Gy can cause skin erythema while ≈5 Gy dose range can lead to permanent skin injury. Stochastic effects, including cancer, have a long latency period and the lifetime attributable risk is difficult to quantify. Because of the radiosensitivity of tissues, children have the highest risk, followed by adult women, adult men, and then the elderly.
Role of Radiation Protection measures
Medical uses of radiation result in the maximum number of occupational collective dose. Over the past several years, a spate of scientific evidence has demonstrated the health risks that interventional teams incur while performing life-saving minimally invasive procedures. The health effects range from skin erythema to premature ageing to cancer. Various studies carried by leading health organizations and regulatory agencies have also linked radiation exposure in health practitioners with various other diseases and disabilities. Studies have also made it clear that practical, safe solutions are needed to protect interventionalists and technicians from ionizing radiation who otherwise will have an increased risk of cancers and other malignancies. Protective steps
“As low as reasonably achievable” (ALARA) is the guiding principle of diagnostic and interventional procedures that make use of radiation like interventional cardiology and fluoroscopy. It focuses on using protective equipment like lead aprons and other control measures such as distance from the radiation source.
Use of Radiation Protection Products and Dosimetry
The effectiveness of Radiation Protection Products rely on the willingness of HCPs to wear all the equipment for the duration of the procedure. Radiation Protection Aprons are an essential accessory worn by healthcare providers during most medical procedures involving ionizing radiation. They play a cardinal role in protecting the healthcare providers from the damaging effects of ionizing radiation generated by X-ray systems, C-Arm systems, Cath labs, Fluoroscopy Systems and CT.
Protective lead Aprons with a thyroid collar is standard for radiation protection in Cath labs. Additionally, safety accessories such as Radiation Protective eyewear, Radiation Protection gloves, lead barriers, lead drapes mounted on the patient table should be used by interventional Cardiologists to minimize radiation dose accumulated over a time period. Other Radiation Protection accessories such as Head Shield, Gonad and Ovarian shields provide protection to vital organs exposed to radiation hazards and need extra attention, however not frequently practised in Interventional procedures.
Guidelines also state using dosimeters by health practitioners to be worn under the apron as an additional safeguard if lead <0.5 mm is used. The rationale for wearing personal radiation dosimeters is that interventional HCPs will be restricted from procedures if monthly dosage limits are met or exceeded.
Control methods
Other protection methods include shielding and distance from the radiation source. There is an array of shields including equipment-mounted, ceiling- and floor-mounted available. But, research has shown that proper positioning of this equipment is essential to reduce radiation exposure, and that “gaps” between various ceiling- and table-mounted shields can occur.
Distance from the radiation source is a core element of radiation exposure reduction. Recent advancements in robotic technology have enabled PCI to be performed behind lead-shielded equipment that is not at the bedside, i.e., at a distance from the beam, and the use of robotic systems have been shown to significantly reduce the amount of scatter radiation to which an operating physician is exposed.
The utility of radiation safety
The duration of radiation exposure, distance from the radiation source, and physical shielding are the key facets in reducing exposure. The exposure duration can be minimized in several ways. When exposing a patient to radiation, the technician or physician should preplan the required images to avoid unnecessary and redundant exposure. Decreased exposure can be achieved instead by using pulsed fluoroscopy, which obtains about five images per second without sacrificing imaging quality. Lastly, exposure duration should be limited whenever possible.
The writer is president, Medical Imaging at Trivitron Healthcare Pvt Ltd.
