Do you use Mobile C-Arms during procedures in your operating room, medical department or clinic? It’s important to understand the different options for dose reduction.
Today’s C-arms offer a variety of dose reduction options. Regardless of the method you use, it’s important to establish a quality assurance system that consists of the following:
- Establish system responsibility and responsibility within a particular department for the use of radiation protection and the use of X-ray equipment.
- Operators of the equipment should have protocols for radiation knowledge, training and protection. It’s especially important to understand the factors that influence image quality and radiation dose.
- Personnel should be educated and trained regarding procedures and radiation dose. In addition, training and education should be repeated on a regular basis to ensure competency.
- Protocols should also be in place regarding system maintenance and adjustments.
Radiation Dose Control
An automatic system that regulates the entrance skin dose rate to patients to give a constant dose to the detector usually performs the adjustment of fluoroscopy parameters (kVp and mA). That’s why the entrance skin dose to the patient will vary between different patient thicknesses and densities in order to get a constant dose to the system detector.
Pulsed fluoroscopy is when the radiation is switched off and on in short intervals during the exposure. This results in a decreased dose to personnel and your patient. Keep in mind pulsed fluoroscopy can be perceived as being somewhat jerky when dynamic processes are being monitored.
You can magnify an area on the monitor by zooming on the monitor or by magnification on your detector. When you zoom on the monitor, it doesn’t change the dose. If you are using an image intensifier system, the patient’s skin dose will often increase when the magnification is being used. As a rule, when you increase the image quality, the patient’s skin dose will also increase and also increased the amount of scattered radiation to your personnel.
- Always use the automatic dose control
- Use the pulsed fluoroscopy only if it is practically achievable
- If you decrease the exposure to patients, it also decreases the dosage to staff.
Scattered Radiation
Scattered Radiation will be created when exposing a patient. The patient is the main source for dose to the staff. The primary part of the scatter will be scattered in the direction of the X-ray tube. The best placement of the x-ray tube during fluoroscopy is under the patient and the detector as close as you can to the patient.
An effective method to reduce scattered radiation is collimation of the radiation field. In addition, the image quality will increase because less scattered radiation will hit the detector which will result in the loss of image contrast. Collimation can usually be done without using fluoroscopy.
Primary Radiation Field
You should avoid the primary radiation field, as the intensity is 100-1,000 times higher than just outside the radiation field.
Screening Time
It’s important not to use more fluoroscopy than necessary. The last-image-hold is usually sufficient for an orientation and sufficient as documentation for the procedure.
Distance
If the distance to the radiation source (the patient) is doubled, the radiation will be reduced to a ¼, as scattered radiation is inversely proportional to the square of the distance from the source. This will impact both the staff dose and patient dose. If the distance from source to skin is short, it can result in high skin doses. You should also be careful when angled projections are used. By taking a step back from the patient, you can reduce the radiation impact. However, if staff is standing far from the patient, taking a step back or towards the patient will have less of an impact.
Shielding
Lead aprons should be used by all staff during a procedure. As a rule, physicians standing still near the patient during their procedure should be wearing an apron covering the front and reaching to the knees. Scrub nurses that traditionally move around should wear an apron that covers the back and front. If using long fluoroscopy times and over-couch tubes, it’s wise to use thyroid shielding.
Talk To An Expert
If you’re looking for medical imaging equipment for your clinic, practice, hospital or urgent care, talk to the experts at Atlantis Worldwide. Refurbished or used medical imaging equipment can often deliver the performance you want at a much kinder price. Plus, you still get substantial warranties.
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- Comparing The GE Innova Digital Cath Lab Family: 2100, 3100 & 4100
- Top 7 C-Arms for Your Orthopedic Practice
- Free C-Arm Resources
About the author: Vikki Harmonay
