Using X-rays, computed tomography and magnetic resonance imaging, interventional radiologists and other clinicians can today carry out a number of minimally-invasive procedures that in the past would have required time-consuming and expensive surgery. However, this has also meant that more clinicians are potentially exposing themselves to high levels of radiation.
Cardiologists, cardiac surgeons and vascular surgeons are performing more and more percutaneous cardiac valve repairs and endovascular aortic repairs. In neuroradiology, the number of stroke treatments with thrombus aspiration is rapidly increasing and interventional therapy of liver metastasis with radionuclides is a new technique.
Reinhard Loose, professor of radiology at Erlangen University in Germany and the chairman of the European Society of Radiology’s Radiation Protection Subcommittee, explained:
A small subgroup of doctors working with ionizing radiation may be exposed higher than before.
Currently, clinicians working in interventional fluoroscopy are exposed, on average, to around two millisieverts (mSv) of radiation every year – well below the recommended annual maximum of 20 mSv. If clinicians take the recommended precautions, they should stay well below these limits, he added.
Nevertheless there are sometimes unshielded parts of the body which may receive significant exposure, like hands and fingers, brain, eye-lens and thyroid gland, if protective devices are not or not always correctly used.
News Materials Are More Expensive
The International Commission on Radiological Protection recently reduced the annual exposure limit for the eye-lens from 150 to 20 mSv after a 20-year study of 35,000 radiologic technicians in the United States showed that even relatively low doses of radiation can increase the risk of cataract.
A discussion has started about whether interventional radiologists are developing a higher rate of brain tumours.
There are 10 ways clinicians can reduce their exposure to radiation, Prof Loose said. These include limiting the length of time of exposure; reducing the dose as much as possible; maintaining distance from the source of radiation; and shielding with the use of aprons, thyroid shields, glasses and gloves.
Lead has been the traditional material for shielding but companies such as Wolfxray and Xenolite are beginning to use alternatives as lead is toxic, heavy and cannot be disposed of in landfill. Lighter weight materials include composites of tin, rubber, PVC, antimony, tungsten, bismuth or other elements. The new materials tend to be more expensive and a middle option, produced by Xenolite for example, is a composite of lead and other materials.
A Protective Lead Cabin with Holes for the Arms
Pierre-Marie Lemer, chief executive of Lemer-Pax, a French company making protective radiological equipment for the healthcare, aviation and nuclear industries, has been working on alternatives to lead for the last 20 years.
Hospitals are still using lead because it is the cheapest metal. However, they don’t think of the total life cycle of the product. Our products are more expensive at the beginning but in the long run they will save a hospital money.
He explained that his company’s protective aprons are 35% lighter than an equivalent lead product. “Our products are much better for the people wearing them as they won’t be straining their shoulders or working so hard.”
Another solution produced by Lemer-Pax is a protective lead cabin with holes for the clinician’s arms. This avoids the need for heavy protective clothing – just a pair of gloves – but may not be the easiest equipment for carrying out delicate procedures.
Dosimeters That Track the Amount of Radiation
Other more technological products include dosimeters that track the amount of radiation both patients and clinicians have been exposed to. Guidelines produced by the Joint Commission in the US, which came into effect last year, had a suite of recommendations, including that healthcare providers monitor radiation doses received by patients and staff.
Phillips DoseWise system includes the DoseAware personal dosimeter which gives staff immediate feedback on how much radiation both they and their patients have been exposed to and how their behaviour has affected it. Dominic Siewko, radiation health and safety officer at Phillips, said the product should be used with the normal protective equipment such as aprons, shields and gloves.
“The Joint Commission is asking HCPs to track and analyze patient dose with the intent to identify trends and opportunities to lower dose. Providers realise they need software to help them [monitor the dose] automatically. While this could be done manually it would be very time consuming,” he explained.