Radiation safety in medical imaging is crucial for patients being scanned and technicians or physicians in the vicinity of the equipment. Exposure to radiation in fluoroscopy equipment such as C-arms comes from two primary sources;
- Scatter – radiation that bounces off the patient
- Leakage – radiation coming from the X-ray tube
How Does a C-Arm X-Ray Machine Work?
After the generator emits X-rays, they penetrate the body, and the image intensifier converts the X-rays into an image. The image is displayed on the monitor to help a physician diagnose and treat the patient’s condition. The C-arm x-ray machine can move vertically, horizontally, and around the axes, enabling technicians to easily capture an image from all angles.
Scatter radiation is considered more prevalent and should be minimized by all means possible. Technicians and physicians in radiography or medical imaging fields can rely on the following tips to protect against radiation:
One of the common errors technicians make is placing the X-ray tube too close to the patient. If the X-ray tube is too close to the skin, the skin dose increases, and the image is blurry. As a result, the technician is required to take another X-ray image, thus exposing the patient to more radiation. As a rule of thumb, the patient should be positioned far from the tube, approximately 12 to 15 inches.
ii. Adjust radiation output
Although technicians cannot protect patients from radiation totally, they can reduce radiation exposure by adjusting radiation output or time of exposure. Newer C-arms effectively adjust radiation output by switching the beam on and off to reduce patient dose. With such a feature, physicians can easily inspect the image even if the radiation beam is off. Adjusting radiation output can help decrease the amount of radiation the patient is exposed to and scattered to other personnel in the room.
How can you reduce radiation scatter?
- Imaging magnification should be used only when necessary because it increases radiation dosage.
- The beam should not be directed through the patient at an oblique angle. In an oblique angle, the x-rays travel through more tissue and long distance in the body. If you must use an oblique angle, ensure the image intensifier is tilted towards you. Tilting the intensifier towards your legs reduces radiation exposure to your upper body, i.e., head and neck.
- Always position yourself on the same side as the patient (the image intensifier side) and not the x-ray tube.
- Always shield the patient’s sensitive organs, for example, the eyes, thyroid, and genital organs.
iii. Wear protection
The amount of radiation absorbed by the technician is equivalent to the dose received by the patient. A physician absorbs approximately 0.1% of the patient’s dose via scattering radiation and additional radiation due to leakage via the side of the tube housing. All the personnel in the room adhere to these safety guidelines:
- Wear 0.5 mm lead-equivalent aprons to avoid scattered radiation. When storing the aprons, always hang them to prevent degradation.
- Wear leaded eyeglasses, gloves, and thyroid shields when performing a fluoroscopy
- When operating the C-arm, use screens suspended from the ceiling, table curtains, and lateral shields to protect yourself against scattered radiation
- All technicians in the room are advised to wear dosimeters/film badges over their aprons. This is important to measure and record radiation exposure to unprotected body parts.
Technicians should wear two radiation dosimeters:
- One at the collar near the thyroid gland monitors scatters and leakage radiation in the room.
- The second dosimeter should be beneath the lead apron to ensure very low amounts of radiation pass through the apron.
iv. Track radiation exposures
It is important to understand that radiation-induced injuries are not readily apparent. Therefore, since radiation effects may not manifest themselves until weeks or months after exposure, tracking radiation exposure is highly recommended. If you use fluoroscopy equipment regularly, wearing protection and tracking radiation is crucial to avoid potential radiation exposure unknowingly. You can also track dose rates for all the personnel who regularly use the C-arm to prevent higher exposures and serious radiation injuries.
Regular training is vital to ensure everyone understands what they are required to do at all times. Do not assume that everyone is aware of the radiation risks and precautions. It is up to the technicians to ensure and guarantee the safety of the staff. If you are unsure about the procedures in the facility, talk to the management to avoid potential exposure.
Technicians are advised to step away from the C-arm during fluoroscopy to reduce radiation exposure. Remember, only trained personnel with the proper personal protective equipment (PPE) should be in the room during fluoroscopy. Although recent studies show that the total amount of radiation dosage during fluoroscopy is safe, protection should be a priority. It is possible to get cancer from C-arm with repeated radiation exposure. Therefore, technicians should adhere to radiation safety precautions and safety programs.