C-Arm X-Ray Machines: All You Needed to Know

A C-arm is an imaging scanner intensifier. The name derives from the C-shaped arm used to connect the x-ray source and x-ray detector to one another. C-arms have radiographic capabilities, though they are used primarily for fluoroscopic intraoperative imaging during surgical, orthopedic and emergency care procedures. The devices provide high-resolution X-ray images in real time, thus allowing the physician to monitor progress and immediately make any corrections.

X-ray image intensifier

An x-ray image intensifier (XRII) is an image intensifier that converts x-rays into visible light at higher intensity than mere fluorescent screens do. X-ray imaging systems use such intensifiers  (like fluoroscopes) to allow converting low-intensity x-rays to a conveniently bright visible light output.
Through its intensifying effect, the viewer can more easily see the structure of the imaged object than fluorescent screens alone. The XRII requires lower absorbed doses due to more efficient conversion of x-ray quanta to visible light.
Permanent/Fixed Fluoroscopic Systems
C-arm fluoroscopy
There are two main configurations of permanently installed fluoroscopic systems. One class commonly utilizes a radiolucent patient examination table with an under-table mounted tube and an imaging system mounted over the table. The other is commonly referred to as a C-arm system that is used where greater flexibility in the examination process is needed.
The C-arm systems are commonly used for studies requiring the maximum positional flexibility such as:
Angiography studies (peripheral, central and cerebral);
Therapeutic studies (Line placements, transjugular biopsies, TIPS stent, embolizations);
Cardiac studies;
Orthopedic procedures
How does a mobile C-arm X-Ray machine work?
Mobile Fluoroscopic System, also known as portable or mobile C-arm, comprises a generator (X-ray source) and an image intensifier or flat-panel detector. The C-shaped connecting element allows movement horizontally, vertically and around the swivel axes, so that X-ray images of the patient are produced from almost any angle.
The generator emits X-rays that penetrate the patient's body. The image intensifier or detector converts the X-rays into a visible image displayed on the C-arm monitor. Physician can check anatomical details such as bones and the position of implants and instruments at any time.
Flat-panel detectors VS Image intensifier
Flat-panel detectors (FDP) are increasingly replacing image intensifiers (II) on mobile C-arm systems, part of a migration of technology once available only in fixed room systems.
The advantages of this technology include: lower patient dose and increased image quality and no deterioration of the image quality over time.
Despite FPD's higher cost, the noteworthy changes in the physical size and accessibility for the patients is worth it.
3D imaging
Three-dimensional (3D) C-arm computed tomography is a new and innovative imaging technique. It uses two-dimensional (2D) X-ray projections acquired with a FDP C-arm system to generate CT-like images. To this end, the C-arm system performs a sweep around the patient, acquiring up to several hundred 2D views. They serve as input for 3D cone-beam reconstruction. Resulting voxel data sets can be visualized either as cross-sectional images or as 3D data sets using different volume rendering techniques. Initially targeted at 3D high-contrast neurovascular applications, 3D C-arm imaging has continuously improved over the years and  now provides CT-like soft-tissue image quality. In combination with 2D fluoroscopic or radiographic imaging, 3D C-arm imaging provides valuable information for therapy planning, guidance, and outcome assessment all in the interventional suite.
Potential safety issues with C-Arm X-Ray machines
Failure of the x-ray beam collimation may lead to primary beam x-ray exposure outside of the selected image intensifier input area. This would result in image degradation. Light generated outside the area of the image intensifier input at magnification causes additional loss of contrast of the image with increased noise. Additionally, unnecessary additional dose to the patient would result. If the C-arm or fittings are damaged, the x-ray tube and intensifier may become misaligned resulting in image degradation or loss, as well as presenting a potential injury to staff and patient if the structural integrity of the C-arm or mounted components are compromised.