Making X-ray detectors thin, light and flexible

Rouzet Agaiby, Senior Business Development Engineer

April 18, 2017

Several market segments depend on X-ray imaging for non-destructive analysis.

X-ray scannerX-ray imaging is used in pipe inspection to check for cracks or fractures through dense objects. Dentists use them to image teeth quality and nerves. Medics depend on them for their diagnosis during static imaging or even during live surgical procedures.

X-ray systems historically used analogue films similar to cameras in order to capture images, which then had to be developed in order to show the image. Analog films were then replaced with a photosensitive phosphor imaging plate which could be read by a laser scanner or a computer radiography reader. This had the advantage of not requiring chemicals and time to develop films, but the imaging plate was heavier, more brittle compared to analogue films and had to be replaced after several hundred uses.

X-ray systems today are bulky, rigid and heavy

Today the phosphor imaging plate in many X-ray systems has been replaced with a digital detector that is composed of three key components: an optical image sensor (usually based on amorphous silicon on glass, or silicon CMOS transistor array technology), a scintillator and read-out circuitry. On exposure to X-rays, the scintillator changes the X-rays to light, the optical image sensor changes the light to electrical signals and the read-out circuitry reconstructs the image which can be read on a computer. The advantage of this technology is that it does not require any specific reader or chemicals to read the image, and this enables it to be used in capturing real-time images during surgical procedures. However, this comes at the expense of a heavier X-ray detector. In some cases, the scintillator is replaced with a photoconductor which changes the X-rays directly to an electrical signal read-out by a transistor array. Such systems are still heavy as most of the weight, bulkiness and limited robustness come from the transistor array.

Flexible X-ray detectors can transform medical diagnostics and non-destructive testing

A new transistor array technology that is made of thin plastic instead of glass and uses organic materials can potentially replace the amorphous silicon glass-based technology in order to make more robust, thin and light-weight X-ray detectors that can be used in non-destructive imaging, general radiography, fluoroscopy and dental applications. Next time you’re at the dentist and need a dental X-Ray, imagine if the dentist didn’t need to insert a bulky detector into your mouth, but rather used a flexible X-ray detector that conforms to your gums. Another advantage of making X-ray detectors thin and light is that X-ray units will be lighter and smaller – meaning they can be deployed in hospitals or remote locations. It turns out that the benefits of using organic transistors are electrical as well as mechanical: the incredibly low leakage of organic transistors compared to silicon means that lower X-ray doses can be used for the same image quality. 

Integrators will find it easy to replace the brittle amorphous silicon glass-based technology with the flexible organic transistor technology without changes to their system design - the only change to their detector will be the image sensor while the scintillator and read-out electronics will remain the same.

Cross-section of an X-ray image sensor

Cross-section of a conventional glass-based X-ray detector (left) and a plastic-based X-ray detector (right)

If you want to learn more about FlexEnable’s integrated image sensor solutions for flexible X-ray and other photo-imaging based array sensors, contact us at imaging@flexenable.com.

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