Radiation protection of patients in gastroenterology

Frequently asked questions by the health professionals

? Are there guidelines for radiation protection of patient in gastroenterological procedures using fluoroscopy??
? What are typical radiation doses associated with gastroenterological procedures??
? Can I be sure that I am delivering the lowest possible dose to my patient if I am using state-of-the art digital equipment??
? Why is collimation an important feature of dose reduction??
? Is risk to patient per procedure the same regardless of the patient??
? How do I know how much dose I delivered during a procedure??
? Is there a difference in radiation dose between diagnostic and therapeutic procedures??
? How to deal with radiation protection of a pregnant patient??
? How to deal with radiation protection of a child??

? Are there guidelines for radiation protection of patient in gastroenterological procedures using fluoroscopy?

Yes.?

The IAEA in cooperation with World Gastrointestinal Organisation (WGO) and American Society for Gastrointestinal Endoscopy (ASGE) has prepared guidelines that are also available on the WGO website.
The main features of the guidelines

Procedure-related:

• Minimize fluoroscopy time;
• Use collimation;
• Take as few radiographic images as possible;
• Use magnification appropriately;?
• Decrease the patient to image receptor (image intensifier or flat panel detector) distance;?
• Increase the X-ray tube to patient distance;?
• Be aware of tube angulations.?

Equipment-related:

• Use the lowest manufacturer’s setting of fluoroscopic dose rates and the highest kVp consistent with maintenance of image quality;?
• Position the X-ray source relative to the patient and staff so as to deliver the least possible dose;?
• Use pulsed fluoroscopy rather than continuous, and use the lowest pulse frequency compatible with adequate image quality;?
• Use last image hold and image capture;?
• Be aware of alarm levels for time and higher dose rates in fluoroscopy;?
• Make sure appropriate quality control is performed.?

??What are typical radiation doses associated with gastroenterological procedures?

^[HA] HART, A., WALL, B.F., Radiation exposure of the UK population from medical and dental X-ray examinations. NRPB-W4 (2002)

^[OL] OLGAR, T., BOR, D., BERKMEN, G., et. al. Patient and staff doses for some compelx X-ray examinations, J. Radiol. Prot. 29 (2009) 393-407.

Read more:

• HART, A., WALL, B.F., Radiation exposure of the UK population from medical and dental X-ray examinations. NRPB-W4 (2002)?
• OLGAR, T., BOR, D., BERKMEN, G., et. al. Patient and staff doses for some compelx X-ray examinations, J. Radiol. Prot. 29 (2009) 393-407.

?

? Can I be sure that I am delivering the lowest possible dose to my patient if I am using state-of-the art digital equipment?

No.?

Digital equipment including flat panel detectors has the potential to reduce radiation exposure if used properly. But 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 with storing 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.

? Why is collimation an important feature of dose reduction?

Reducing the field-of-view is beneficial in

• reducing the stochastic risk to the patient by reducing the volume of tissue at risk;?
• reducing scatter radiation to the patient and in-room personnel;?
• reducing potential overlap of fields when the X-ray beam is reoriented.

? Is risk to patient per procedure the same regardless of the patient?

No.?

Many patient-related factors will affect the dose and the risk. These include:

• Body mass or body thickness in the beam: larger, thicker patients require higher doses to achieve quality images;
• Young age: young patients are more sensitive to radiation;?
• Patient’s disease and indication for procedure: the more difficult the procedure, the higher the dose;?
• Previous radiation exposure: exposures are cumulative;?
• Radiosensitivity of some patients (ataxia telangiectasia); connective tissue disease and diabetes mellitus: some conditions increase radiosensitivity.?

? How do I know how much dose I delivered during a procedure?

You must record the dose area product (DAP), currently known as kerma-area-product (KAP), and the fluoroscopy time. This will allow comparison with diagnostic reference levels or guidance levels.?

? Is there a difference in radiation dose between diagnostic and therapeutic procedures?

Yes.?

The screening times and thus the doses will generally be higher for therapeutic procedures like stent insertion, stricture dilatation, stone extraction, lithotripsy, needle knife sphincterotomy, multiple wire use as compared to diagnostic fluoroscopies.

? How to deal with radiation protection of a pregnant patient?

When the medical exposure of a pregnant woman is considered justified, special consideration of optimization is warranted. Most importantly, the X ray beam size should be minimized (collimated) with appropriate exposure factors selection (pulsed exposures, minimal patient to detector distance, etc.). If the foetus is not located directly in the primary radiation field, a minimal amount of scattered radiation within the mother’s body may still reach it. However, this amount to the foetus is generally very low and not harmful.

A contact shield placed externally is?ineffective in providing protection. Additionally, the automatic exposure control may even increase the dose delivered if shielding is within the primary radiation field. However, shielding may be applied according to professional judgement for very apprehensive patients or caregivers who desire it, following an explanation of its risks and benefits.

? How to deal with radiation protection of a child?

All guidelines stated above apply with a special emphasis on protection of radiosensitive organs using appropriate beam?adjustment (collimation) and appropriate exposure factors selection (minimal distance between patient and detector, orientation of both the tube and patient, etc.).