Radiation protection of staff in gastroenterology

» How much radiation is safe for me as a gastroenterologist?

No amount of radiation can be considered entirely safe but acceptable limits for staff have been recommended by the International Commission on Radiological Protection (ICRP) and adopted by international organizations and most countries with minimal change. The recommended dose limit in terms of effective dose is 20 mSv per year or 100 mSv in 5 years. This is over and above the radiation dose one gets from natural sources, which varies from place to place but is 2.4 mSv per year as a global average.

» How much radiation may I get in ERCP?

With an average workload, less than 2 mSv per year should be anticipated for a person using a lead apron and practicing radiation protection norms. It is important to use a lead apron and practice radiation protection. Adequate thyroid shields, leaded eyewear and good technique should further reduce the dose.

» How do I protect myself and my staff?

Best practice includes positioning of the X-ray tube below the table as far away as possible, positioning oneself as far away as possible from the X-ray tube and patient, wearing a protective apron with lead equivalence of 0.25-0.5 mm, thyroid shields, and leaded eyewear. Maintaining X-ray equipment in optimum operating condition, using pulsed fluoroscopy, minimizing fluoroscopy time, limiting radiographic images, using shielding barriers, collimation and reduced use of magnification will help to reduce X-ray exposure to the staff.

» What will increase my radiation risk?

First and foremost if a lead apron is not used, it can make major difference. A lead apron attenuates approximately 95% of the scattered radiation that reaches the wearer. Lead rubber flaps, sliding lead screens and lead glass eye wear are extremely important and again cut down radiation by more than 95%. Anything that increases the amount of radiation exposure e.g. longer fluoroscopy times, more radiograph images generated, proximity to the radiation source, positioning the X-ray source above the patient, and your closeness to the patient will increase the radiation dose and potential risk from ionizing radiation. Patient and staff exposure are related. Any action to reduce patient dose will also help staff.

» Does newer equipment provide better radiation protection?

Not always. Digital equipment including flat panel detectors has the potential to reduce radiation exposure if used properly. Experience shows that lack of understanding of the features of digital imaging systems has resulted in higher radiation exposures to staff and patients. The reason for increased radiation dose from digital equipment stems from the fact that overexposure in digital imaging results in better quality images and can go undetected. Modern equipment provides the facility to store fluoroscopically generated images, reducing the need to have cine or radiographic images that require much higher exposure than fluoroscopic images. Using this feature can help to reduce dose. 

» Is the exposure to a gastroenterologist higher or lower than to an interventional cardiologist?

It is lower based on typical workload. Current published data indicate that radiation dose to a gastroenterologist can be substantially lower than that to an interventional cardiologist. Typically the fluoroscopy times in gastroenterological procedures are much lower than in cardiac interventional procedures. 

» Can I work my full professional life with radiation in operating rooms and have no radiation effects?

Yes, with use of good practice and adequate protection from available aprons, shields, eyewear and use of proper technique.

» What is the source of radiation in endoscopic procedures?

The primary source of radiation is the X-ray tube but staff are exposed to scattered radiation mostly from the patient and thus the patient becomes the important source of radiation for the staff. Reducing radiation exposure of the patient thus has impact on staff exposure. Distance from the X-ray source and avoiding hands and body parts in the direct beam will reduce the exposure.

» How important is it to use protective eyewear and thyroid shield?

Recent studies show increased sensitivity of the eye lens to radiation and thus protection of the eye using lead glass eye wear is very important. The adult thyroid is much less sensitive to radiation as compared to child. However, continued use of thyroid shield is in line with ALARA (as low as reasonably achievable).

» How many radiation badges should be worn and how and where should they be worn?

Best practice would demand two badges, one below the lead apron at chest level to estimate the effective dose and another to monitor exposure to the head and neck worn at the collar level above the protective apron. In most countries use of a personnel monitoring badge is mandatory. However, many countries lack recommendations on the use of second dosimeter at collar level.

» Summary points to remember.

  • Be aware of the indications - use procedure that employs ionizing radiation only when risk-benefit considerations are clearly in favour of benefit;
  • Keep X-ray tube at practical away from the patient and image intensifier as close to patient as possible;
  • Use ALARA (as low as reasonably achievable) principle;
  • Use personal protective devices: lead apron, lead glass eye wear, thyroid shield and other shielding in particular for eye, legs. 

Ensure that they are well maintained and of proper lead equivalence. Know which side to stand (better away from X-ray tube and be on image intensifier side). Use TDS (Time, distance, shielding) principle. 

Use inverse square law: step behind wherever possible;

  • Use patient dose management techniques: collimation, filter, lesser magnification, pulsed fluoroscopy, lesser number of pulses, avoid or reduce use of oblique views;
  • Ensure that equipment is tested for QC and radiation output is not more than standard as compared to published values;
  • Pregnancy and otherwise: Cut down irradiation of fetal/abdomen (non-target area) by collimation and shielding of primary beam;
  • Dosimetry: Use dosimeter for yourself and staff;
  • Patient dosimetry: record dose area product meter (DAP) values or other dose indicator. If DAP is not available, record at least fluoro time and number of images, along with kVp, mAs;
  • Avoid unnecessary personnel inside the X-ray room.