Mobile X-ray Units.

Table of Contents

Mobile x-ray units, also known as portable x-ray machines, are radiographic units that can be transported to the patient’s location to obtain x-ray images. They are used when the patient cannot be moved to the radiology department due to immobility or critical condition.

Mobile x-ray systems are often used to perform chest radiography to patients who cannot be moved to the Radiology department. As such, a mobile x-ray equipment is designed with such unique characteristics to be able to be moved within limited spaces like in between hospital beds in small wards.

Some Features Of Mobile X-ray Units.

Mobile x-ray units are mounted on wheels or casters so they can be easily maneuvered between locations. Some units can also be moved on tracks installed in the ceiling.

Mobile x-ray units have an x-ray tube and image receptor that can be positioned as needed for the exam. Some units have an articulating arm to allow different projections.

Mobile x-ray units are battery-powered so they can operate without power cords. The batteries are recharged when the unit is not in use.

Mobile x-ray units have safety features to minimize radiation exposure to staff, including lead shielding and a control panel for operating the unit from a distance.

Mobile x-ray units produce digital radiographic images that can be transmitted electronically for interpretation, so there is no need to transport film cassettes back and forth.

Mobile x-ray units have a smaller field of view and lower image resolution compared to stationary radiographic equipment in the radiology department. But image quality is adequate for initial diagnostic purposes.

Mobile x-ray units require frequent maintenance and quality assurance testing to ensure proper functioning for safe and effective use at the patient site.

Mobile x-ray units come in different sizes depending on their intended use. Smaller units can be used at bedside for extremity exams, while larger units with more power are needed for chest x-rays and scans of larger body parts.

Digital flat panel image receptors are commonly used as they provide good image quality without the need for film cassettes. Some units use computerized radiography (CR) plates that require manual film cassette insertion. CR is becoming less common.

The x-ray beam is manually aligned for each exposure. Laser guides or other alignment aids are used to properly center and level the beam over the image receptor.

The technologist manually sets technical exposure factors like kVp, mAs, and collimation for each view based on the body part and patient size. Automatic exposure control is typically not available.

Due to the greater chance of suboptimal positioning and alignment outside the radiology department, extra views are often needed to get diagnostic quality images. This increases patient dose.

Operators require special training in using mobile x-ray equipment safely and effectively at patient sites. Challenges like space constraints, thin walls, limited access to power outlets, and suboptimal lighting conditions must be considered.

Higher radiation dose limits are allowed for mobile radiography compared to general radiographic rooms due to the greater operational difficulties. But radiation exposure should still be kept as low as reasonably achievable.

Table:- Recommended basic characteristics as minimum requirements for a Mobile X-ray units.

Mobile unit	Type	Mobile X-ray unit with sliding column
	Focal point distance from floor	55 to 205cm
	Batteries	Separate batteries for drive and generator control
	Power for charging	Single-phase
	DAP meter	Yes
Generator and x-ray tube	Power	20 kW
	Tube voltage	40-125 kV
	mAs range	0.1 – 500 mAs
	Exposure times	0.001-1.25 s
	Focal spot (S/L)	0.3/1.0
Wireless portable detector	Type	CsI
	Housing	Carbon fiber
	Detector sizes	35 x 43 cm; 24 x 30 cm
	Pixel size	148 mm
	Image resolution	up to 3.4Lp/mm

Mobile X-ray Units.