Mobile X-ray equipment

1. X-ray mobile and detector

1.1. Detector characteristics

Computed Radiography (CR) and Digital Radiography (DR) detectors are available as digital image receptors for radiography. CR systems use storage-phosphor image plates with a separate image readout process. DR technology converts x-rays into light and subsequently the TFT array will convert this light into electrical charges and finally to a digital image readily available (6).

CR technology uses an indirect conversion process using a two-stage technique. X-Rays are captured at a storage-phosphor screen (SPS) (ex: BaFBr:Eu2+) and then a photodetector captures the light emitted from the SPS and converts the captured luminescence into a corresponding digital image as a latent image result from the exposure. After the exposure, the image plate (IP) inside the cassete is scanned in a separate CR reader device. The readout is a process that follows exposure of the image plate and constitutes the second step of the CR imaging cycle.

Images of CR cassettes can be found in this page

Radiographer inserting a CR image plate (IP) in a CR reader device

DR technology use a two stage technique for conversion. They have a scintillator, such as Cesium Iodide (CsI) that converts X-Rays into visible light at a first stage. That light is then converted - at a second stage - into an electric charge by means of an amorphous silicon photodiode array, allowing the radiographic images to be readily available to the Radiographer in about 1 second.

One of the most interesting recent developments for DR detectors is the in-built wireless component. This allows the detector to be operated with no cable attached, allowing more flexibility in their use, especially in portable radiography.

Wireless DR detectors are battery-powered which allows multiple exposures and need a reliable wireless connectivity to the radiography environment and the portable x-ray mobile equipment.

Images of DR detectors can be found in this page

Different digital technologies are currently available for clinical practice in plain radiography. CR and DR technologies constitute a remarkable improvement based on detector technology developments. The specific properties and capabilities of a digital detector influences the choice of the radiographic technique, the radiation dose delivered to the patient and the diagnostic quality of radiographic.

Although CR and DR coexist at the present time the recommended technology to be used in a COVID-19 patient environment would be the wireless DR portable detector.

The use of a wireless DR detector will allow the Radiographer to have less contact time with potential infected patient, less exposure errors and less retakes, better image quality and rapid image sharing in the PACS system.