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Apr 02, 2021

What Makes One Dental X-ray Imaging System Better Than Another… And Why Does it Matter?

- By Jacqueline Wheeler

I’m Jens Sjödahl, and I’m Sales and Business Development Manager for Direct Conversion. We develop and manufacture next generation X-ray detectors. For the past ten years, our detectors, based on charge integration technologyhave been at the heart of thousands of panoramic and cephalometric dental X-ray systems all over the world.  

And now were taking dental X-ray forward once again. 

Our new detectors will be based on photon counting technology. These devices are at the forefront of image quality, optimise examination times and aid in the overall system reliability. 

But most dentists probably won’t know what X-ray detector they are using or why it’s so important. 

SoI’ve taken a pause from working with the techies and spent some time with dentists themselves, to help them understand why the detector in their X-ray system makes a difference.  

It’s been a fantastic experience, meeting professionals who are passionate about the service they provide and who really care about getting the most advanced, innovative technologies into their practices to achieve this.  

With their insights and questions in mind, I’ve created this simple user’s guide to the astonishing science of photon counting, so you can find out, for yourself why X-ray systems with our photon counting X-ray detectors can benefit your patients and your business 

Why Is the X-ray detector important?  

Buying an X-ray imaging system without understanding the detector at its centre is like buying a car without knowing anything about its engine.   

The detector technology is one of the most significant component in an X-ray system. Resolution and contrast in the image are a direct resultAlso, the sophisticated new image processing technologies and artificial intelligence methods that are now available can extract detailed information from the image, so the type of detector in your system matters.   

How does an X-ray system with a photon counting detector differ from a conventional system?  

The detectors in conventional extraoral X-ray systems are based on Thin Film Transistor (TFT), Charge Coupled Device (CCD) or  Complementary Metal Oxide Semiconductor Technology (CMOS) in which a scintillator converts X-rays into light and the TFT, CCD or CMOS device then converts light into an analog voltage which is further converted into a digital signal. Photon counting X-ray detectors do not have a scintillator. They count every photon and are truly digital from the start. This has a range of features and benefits to the end user.

Will I see more in my dental X-ray image if the system uses a photon counting detector?  

This is why photon counting technology is at the forefront of X-ray imaging.  Conversion to light through a scintillator involves an additional process and this can lead to a blurring or smearing effect.    

However, the images produced using our photon counting detectors are sharp with optimised detail because there is no need for conversion, which is why the process is known as direct conversion.  

Cosmetic and reconstructive dentistry – from implants to facial bone trauma – have their own specific challenges. Signs of osteoporosis, salivary gland disease or other diseases are now falling into the dental remit, especially because many patients visit you more regularly than their doctor. In all these cases, the level of resolution of the resultant X-ray image is very important. 

Explain how the improved image quality could impact on my work  

Photon counting detectors can capture tiny details that might be missed in a conventional X-ray because of blurring or background noise. When you have innovative technology in your practice, you know that you are using every opportunity to protect your patients’ teeth and gums and, from a business perspective, you grow your reputation for delivering a high-quality service.  

However, one of the most exciting aspects of our technology is that enables you to examine bone and soft tissue separately.

Separate bone and tissue? Sounds like a game changer to me. Tell me more. 

Our dual energy imaging technology will allow you to separate out the bone and soft tissue. The science behind this rests on Direct Conversion’s proprietary imaging chip which digitally identifies each X-ray. The energy of each incoming X-ray photon is analysed separately and classified either as low or high energy. 

With dual energy, a standard exposure will produce three images with no additional cost in time or price and no extra dose: a high-quality standard image, like those you are familiar with, but without blurring, as well as low and high energy image. The latter two images can then be used as sources for a sophisticated process known as material separation which produces a soft tissue image and a bone content image.  

You will be able to exclude bone from the image in order to inspect the soft tissue for inflammation. Equally, you might want to look more closely at bone features, and dual energy imaging will allow you to remove the shadow of the soft tissue.  

My typical appointment time is 15 to 20 minutes, so I’m on a tight schedule. Will better images take longer to acquire?  

With more information visible in the image, you can get to the problem quickly.  

It’s worth noting that around 2.7 million panoramic X-rays are taken in the UK each yearand the minimum time spent on the process is around five minutes, a quarter of your appointment time. A system that uses a photon counting X-ray detector can help you minimise time spent reading the image and maximise your chairside time.  

Radiation dose matters to me, my staff and my patients. Is photon counting low dose? 

In a modern low-dose panoramic imaging system, only a few X-rays reach each detector pixel per image captured in the thickest parts of the skull. The readout circuit in a standard digital X-ray detector adds electronics noise that can even be equal to the number of x-rays received. This can significantly reduce the image quality and hide important clinical details.

However, you can reassure your patients – and your nurse – that photon counting detectors can operate with very low dose because, with their pulse height discrimination capability, absence of electronic noise and ability to capture virtually all the X-rays, means there is no impact on the measured signal.

Where low dose is of real value, though, is for those patients who require frequent repeat X-rays because of wisdom tooth removal, prior to implant placement, or where there is suspected pathology of the jaws, such as cysts and the like.  

And when treating children, low dose is always desirable, particularly when they are going through orthodontic procedures2. 

Is the software easy to use? 

A Direct Conversion detector will be a part of the X-ray system, working smoothly behind the scenes, embedded in the system manufacturer’s software that you are used to.  

What is the lifetime of an X-ray system with a photon counting X-ray detector? 

Photon counting detectors use a material called Cadmium Telluride – CdTe. This material is robustly hard and has a long lifetime. It also requires less time for recalibration than traditional detectors; in essence, CdTe prolongs the lifetime and the efficiency of your X-ray unit.  


We would like to say a huge thank you to the dentists who gave their time, shared their expertise and asked the tough questions that helped us put this article together – Dr Nilesh Parmar, Dr Richa Awasthi, and all the participants in the Dental Discussion Group IDS 2019.

We will be releasing news about our forthcoming photon counting dental X-ray detectors, so follow us on Linkedin and Twitter to be at the front of the queue when they become available. 

In the meantime, ask your supplier which detector is powering their system as this will give you some insight into what is behind the design and help you make the best purchasing decision for your work.   

For the tech geeks among you, dig deeper into the science and find out how to be prepared for a future of more detailed diagnostics and complex treatments 

And if you want to know why the leading dental X-ray system manufacturers like to do work with us, read our Top Ten Reasons  To Chose Direct Conversion blogs.    

1 (Drage, Walker, 2015)

(Drage, Walker, 2015)