A session held yesterday at the Charing Cross International Symposium revealed that there is a widespread lack of physician awareness about the dangers of radiation in the interventional suite. The effect of exposure to radiation has become particularly important with the move from open to endovascular procedures, and delegates heard how no single specialty had a monopoly on bad practice when it came to radiation.
During the session it became apparent that the knowledge base about radiation had not been developed and incorporated into training and that appropriate behaviour in the interventional suite was often ignored, leading to operators receiving unnecessary doses of radiation. Surgeons, who have belatedly started using radiation, interventional cardiologists, interventional radiologists and radiologists are all guilty of bad practice, delegates heard.
“We are not aware of how badly affected we can be and this session turns the spotlight on how little we know. It is very important to become aware and realise the danger before you can start steps to reduce it. Perhaps as a profession we are not doing enough,” said Roger Greenhalgh, London, UK, chairman of the symposium.
Lindsay Machan, Vancouver, Canada, who was invited to comment on the Radiation Exposure session, told delegates that there were “two dirty little secrets” about radiation that he wanted delegates to pay attention to. “The first is that there is no safe dose of radiation; the idea that there is a threshold has now been debunked. The second is that every person in this room has a variant level of the radiation repair genes and there is no test as yet for the repair genes.”
Machan referred to the results of a long-term international study of thousands of workers exposed to radiation in the Chernobyl disaster in 1986, which found that the disaster clean-up crew, no matter where they were located, had the same incidence of cataracts, dispelling the idea of there being a threshold for cataract development. Referring to the outcomes from another 20-year study published by Chodick et al in the American Journal of Epidemiology in 2008 that found that there was no apparent threshold level for technologists to get cataracts, he said: “Everything that you hear about thresholds is absolutely not true. Treat radiation like iodinated contrast and use only as much as needed and no more.”
Machan also told delegates about the work of the late Basil V Worgul, New York, USA, which had shown that there was a possibility that the human population included genetically predisposed radiosensitive subsets.
“Everybody in this room has some degree of radiation damage and not everyone has complex innovations available to help them reduce the dosage. However, the distance from the tube and the importance of magnification cannot be overstated,” Machan said.
A member of the audience referred to currently available tools that enabled the visualisation of dosage in the form of a light or sound alarm. “Everybody wants to avoid radiation, they are just not aware of how their behaviour impacts dose. So if you stand unnecessarily close to the machine, there is an immediate warning and this can teach operators a lot,” he said.
Operator behaviour is driven by various factors
“You cannot overstate the importance of a real time reminder of the dose. Another important thing we have observed is that when our nurses and technologists became aware of their own risk, it changed the dynamic quite considerably. Operators are driven by a different dynamic; we want to get that procedure done, we want to show the photos and have a tendency to ignore [the radiation dose] and the consequences as they might be 20 years away. However, the nurses and technologists are not [driven by the same things]. They are there to do a job. As soon as they realise that they are at risk, it has an amazing impact. They start pointing out the fluoro time, question where they are asked to stand, and if you are doing a pedal puncture they might not stand behind the foot and hold the foot for you,” Machan said.
Another member of the audience made the point that they had measured and found that the radiation exposure was less in the hybrid suite as compared to their previous set-up. Their team had also found that the operator steps away just 6% of the time during digital subtraction angiography turns and have been working on educating the entire team. The awareness is lamentable, delegates heard.
Patients suffering burns
“One of the problems is that radiation burns can occur several months after the procedure and often the patient does not connect that to the procedure. Also, due to the fact that the image intensifier is above them, they think that the radiation dose is there. They do not realise why they have a burn on their back and often go to see a physician who does not have radiation in their mind as the cause, so there is a gross underreporting of the problem,” Machan said. The panel also commented that the biggest risks were for health professionals, as they are exposed repetitively during the course of their work. The maximum exposure resulted when branched devices were implanted, and the biggest risks are for health professionals as they are exposed every day.
Is regulation around the corner?
Machan made the point that while the health effects of radiation were one aspect, another issue was that of looming regulation for radiation workers. He pointed to the current practice in some US hospitals of radiation workers “sitting it out” if they had a high reading on their dosimeters. The sit-out period could range from anywhere between a week and a month. “Think of what this would do to your endovascular practice,” urged Machan. “If you have to sit out for a month every couple of months, you cannot actually practise.”
The panellists noted that while there was a wide variation in education and training requirements for personnel to be able to use radiation, there was need for special education for the whole team on to behave in an operating room. Machan also noted that while there were well laid out and appropriate guidelines in place, that the bigger problem was with adherence and enforcement.
Johannes Gahlen, Ludwigsburg, Germany, who spoke on the importance of radiation dosage exposure to patient and operator, said: “It is vital to adhere to the ALARA principle of keeping the dose as low as reasonably achievable. It is important to decrease the beam time, keep your distance from the system, use protective shielding, instruct the team, collimate the field of view, reduce the frame rate use use low dose programmes,” he said.
Following Gahlen’s presentation, Koning spoke about the novel X-ray system and how it can reduce radiation doses for patient and staff during endovascular procedures. He presented the results of a study and said that initial findings indicate that a significant radiation dose reduction of up to 75% to staff and patient can be realised for specific procedures.
He continued saying that radiation reduction in complex procedures, such as fenestrated stent graft implantation, means that implementation of lower doses of radiation is sometimes not attainable. He said that reducing radiation dose during the procedure will typically result in lower image quality, which may be unacceptable for clinical success of the endovascular treatment.
In the study, the investigators upgraded their existing C-arch to AlluraClarity (Philips Healthcare), which reportedly resulted in an ability to lower the required radiation exposure without losing image quality and without changing the workflow of the physician.
Koning reported that the results of the study are currently being processed for scientific publication. However, he said that initial findings indicate a significant dose reduction can be achieved. He said image quality was judged to be equal or superior compared to the image quality before installation and interventional work flows were uninterrupted.
Concluding, Koning said: “With the latest generation in imaging systems, we also see promise in increasing patient and staff safety without sacrificing the imaging quality required to provide optimal care.”