Direct vs Indirect Digital Radiography
Discover the differences between direct digital radiography and indirect digital radiography to ensure you find the best X-ray solution for your business.
Compared to the film-screen forerunners, digital radiography solutions offer a wide range of dynamic advantages and require 50-80% less radiation per exposure. But from the two direct radiography processes (direct and indirect), which one best suits your medical imaging requirements?
Let’s explore the definitions, processes, and advantages of direct and indirect digital radiography to find the best solution for your business.
What Is Digital Radiography?
Digital radiography (DR) generates digital radiographic X-ray images on a computer screen and is now considered the accepted technology across most medical institutions. Unlike computed radiology, DR functions without tapes with the X-ray activating hardware to send digital information on the screen.
The digital radiography process requires detectors to take X-ray images. Both these detectors can be separated into direct and indirect. Digital detectors are used across multiple types of radiography including fluoroscopy, interventional and mobile X-ray systems.
Also known as digital detector arrays (DDAs), flat panel detectors provide high-quality digital images with an advanced signal-to-noise ratio and dynamic range.
Digital radiography has numerous benefits, including:
- Shorter exposure times
- Real-time applications
- Enhanced detail identification
- Reduced inspection time
- No need for chemicals
- Portable
So, with the definition and benefits of direct radiography established, how do we differentiate between the two detector types?
What Is Direct Digital Radiography?
Direct digital radiography absorbs X-rays within an electrical charge, converting from the X-ray electrons. With direct digital radiology, you skip a step of generating physical light and go directly to measure electrons.
An amorphous selenium layer or cadmium telluride is placed on a multi-micro electroplate. These layers then interact and generate electrons before enabling an accurate measurement.
Therefore, the direct digital radiography process translates to an electrical current forcing the electrons from top to bottom before measuring directly.
What Is Indirect Digital Radiography?
Indirect digital radiography uses detectors to convert from X-ray to visible light before engaging the electrons. So, compared to direct digital radiography, the indirect detector process contains an additional stage involving the generation of light through a scintillator layer which converts photons to photons of natural light.
Despite this additional stage in the process, indirect digital radiography is the most common form and can be performed in two variations known as:
- Indirect TFT Flat Panel
- Indirect CCD Flat Panels
Both indirect flat panel variations begin with the scintillator layer, either in the form of Gadolinium Oxysulfide (GOS, Gadox) or Cesium Iodine (CsI). GOS is less expensive but not as accurate as CsI.
The Direct Digital Radiography Process
During the direct digital radiography process, X-ray photons impact the photoconductor to directly convert electronic signals.
- Interaction – Electrons interact as high voltage layers cause electronic engagement.
- Conversion – The charge collects electrodes within pixelated forms.
- Output – The image is displayed through a thin flat panel transistor array.
The Indirect Digital Radiography Process
Indirect digital radiography requires an additional scintillator to convert X-ray photons from light, utilising a photodiode matric of amorphous silicon to convert it into an electrical charge.
- Interaction – Scintillator converts X-rays to visible light.
- Conversion – The visible light is converted into an electrical charge.
- Output – The image is displayed via a thin film transistor array.
Direct vs Indirect Digital Radiography
Is there a clear winner for digital radiography between direct and indirect solutions or do we have a suitable system depending on the application? Let’s explore the advantages of both digital radiography processes:
The Advantages of Direct Digital Radiography
The main advantage of direct digital radiography is a higher spatial resolution. As the electrons get pulled down directly, the imaging has less opportunity to spread. So, if the X-ray application is mammography where spatial resolution is essential, direct digital radiography will serve your needs much more than indirect flat panel detection. Direct digital radiography is also a preferred solution when using low-energy X-ray machines.
The Advantages of Indirect Digital Radiography
The advantage of indirect digital radiography is that the readout speed is superior to direct panel detectors. While the resolution is lower, you will get faster results and it’s less expensive. Therefore, indirect flat panel detectors have less resolution capacity but still work well for general-purpose radiography when efficiency is essential, and budgets are tight.
Invest in the Best Direct Digital Radiography Products
If you’re a radiologist in search of high-resolution direct digital radiography imaging equipment, we have a vast selection at Wolverson X-Ray Ltd to fulfil your requirements. As experienced medical equipment specialists, we’ve provided reliable and quality products to our clients throughout the UK for the last 85 years. Our range of direct digital radiography products includes:
IMIX Direct Wireless DR System
- Lightweight ceiling-suspended X-ray tube support.
- A table, wall stand and generator.
The digital system includes a wireless cassette detector and imaging system.
- Table specifications: 2400mm long x 855mm wide.
- Low minimum height tables for optimal patient support.
- Long longitudinal stroke requires less patient repositioning.
Complete with a manoeuvre handle and accessories, including compression belt, lateral cassette/detector holders, foam pads and patient handgrips.
Wolverson X-Ray provides various flexible and high-performance digital imaging equipment in a range of sizes and specifications.
- Vision X DR Imaging Equipment
- Vision V DR Imaging Equipment
- Vision U DR Imaging Equipment
- Vision Air DR Imaging Equipment
- Vision C DR Imaging Equipment
We also have numerous other superior digital radiography products and accessories available. Get in touch for more information, or read our case studies to see how we’ve supported various medical organisations up and down the country.
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