Radiation stewardship for patient and endourologist
Radiation stewardship for patient and endourologist
Minimising radiation exposure for nephrolithiasis procedures requires the endourologist to make adjustments to limit fluoroscopy time, limit time spent adjacent to the patient, irradiate only to observe motion, and use 'last-image-hold' and 'instant replay' whenever possible.
Prof. Andreas Skolarikos (University of Athens, Greece) provided practical tips and tricks to reduce radiation exposure in both the patient and attending endourologist . Patients with nephrolithiasis are at risk for significant radiation exposure from diagnostic imaging. In addition, fluoroscopy used during surgical treatment of nephrolithiasis also contributes to radiation exposure for patient as well as endourologist. Patients receive even more radiation from surgery than from a non-contrast computed tomography (CT) of the abdomen and pelvis. However, a recent survey on the knowledge on radiation exposure and compliance to wearing protective equipment among endourologists indicated substantial lack of knowledge and awareness regarding their occupational radiation . Nonetheless, compared with interventional radiologists, cardiologists, and vascular surgeons, urologists are exposed by far to the highest levels of radiation, with exposure levels over 18-fold compared to cardiologists .
Ionising radiation is an essential part of any urological practice. In general, Prof. Skolarikos said, radiation exposure can be minimised in 2 ways: either by using use no radiation at all or by following the ALARA (as low as reasonably achievable) principles. In the aforementioned survey, only 42% of endourologists were familiar with the ALARA principles . An example of one easy adjustment is the use of ultrasound in percutaneous nephrolithotomy (PCNL) together with fluoroscopy, which reduced the fluoroscopic time and therefore reduced radiation exposure .
In urological practice you want to protect the patient, yourself, and the operating personnel. The primary beam interaction with the patient produces scatter radiation that comes to the personnel in the operating theatre. Anything done to reduce patient exposure will likewise reduce the personnel exposure. Some of the tips and tricks shared by Prof. Skolarikos included:
- Be aware of your patient's previous exposure. The longitudinal exposure of stone patients to ionising radiation from CT imaging and fluoroscopy during surgery is poorly defined.
- Be aware that ionising radiation from the management of nephrolithiasis carries a small but significant increased risk of a secondary malignancy.
- Reduce the fluoroscopy time by adapting simple techniques, like not magnifying the image and keeping the image intensifier close to the patient’s body (see Figure). It is essential to be vigilant of the image intensifier usage, thereby reducing radiation exposure to the surgeon and the patient .
- Keep the C-arm low to the patient, which will improve image quality as well as reducing patient and operator exposure.
- Reduce patient dose by using pulsed instead of continuous fluoroscopy together with collimation, which reduces the scattered radiation produced by 5-fold. . Another trick is to minimise field overlap by not turning the C-arm to extreme angles .
- Avoid digital acquisitions, which leads to 5-10 times higher exposure to fluoroscopy, and rely on the last-image-hold feature. Audible indicators of fluoroscopic time and measures of cumulative dose may further protect against exposure.
- Urologists should always be protected by structural and/or mobile shielding, provided the shielding covers the patient where scattered radiation would originate, and personal shielding (i.e. gown, thyroid collar, optional eye protection, but not radiation protective gloves, as these can increase the radiation dose to the hands).
- Always use the X-ray source underneath the patient (i.e. under-couch), and as close to the patient as possible, as 1 study demonstrated operator radiation exposure to be significantly lower for under-couch versus over-couch setups (P<0.001) .
- Patient positioning remains a debate, although a recent randomised controlled study showed that ultrasound-guided PCNL either in prone or supine position is as effective, feasible, and safe as conventional nephrolithotomy with zero radiation exposure [9,10].
Prof. Skolarikos concluded that urologists and surgical staff require additional training in radiation and radiation exposure. He urged that radiometers should be evaluated monthly. The rules for staff protection have been well described , but it is well known that the exposure of staff is considerably lower than the exposure to the surgeon.
Figure: Effect of the distance from the image intensifier to the X-ray source on magnification, dose, X-ray loss, and scatter radiation 
Figure kindly provided by Prof. Skolarikos.
Keywords: Radiation Exposure; Fluoroscopy; Kidney Calculi
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Top image: © Mohammed Haneefa Nizamudeen
The content and interpretation of these conference highlights are the views and comments of the speakers/authors.