Computed radiography or CR is one of the replacements for conventional X-ray film radiography.
It uses Phosphor imaging plate to make a digital image.
Hence, rather than the film, the plate exposes to X-ray and gamma rays.
These image plates are reusable plus the results are produced in a very short amount of time.
The image receptor is held in a cassette instead of a traditional film screen.
Therefore, it is a bridge between classical and digital radiography.
If you are looking to purchase computed radiography technology, then this article is for you.
Learn about its advantages, uses, and comparison to digital radiography to know what is best for your practice.
What is Computed Radiography Technology?
CR uses photostimulable phosphor as the image receptor.
These are cassette-based plates that then scan in the computerized system to produce a digital format.
CR uses photostimulable luminescence.
It absorbs radiation and traps electrons at energy levels.
When these plates get exposed to X-rays and gamma rays from the radiation is stored in the phosphor layer of the casing.
The radiation excites the phosphor electrons and traps them in the lattice till they are stimulated by the next round of illumination.
The scanner reads out the latent image using a laser beam focus of 0.1 mm or less.
This allows the trapped electrons to return to their valence bands.
Due to this stimulation, the plate emits blue or violet light with an intensity proportional to the amount of radiation.
This light is captured and digitized to produce the digital array.
A photomultiplier i.e. a highly sensitive analog device detects the light and converts it into an electric or digital signal using an analog to digital converter.
The stored image can now be visible on a computer monitor or pixel matrix for evaluation.
The image plate is reusable, after reading, the technician can erase it using a high-intensity light source that is white light.
They can come in use for about 1000 times or more.
Considerations and Equipment
Technically, CR is the bridge between the class and digital technologies but it can also be a replacement for the conventional X-ray film.
The imaging plates use the same radiographic methods as the films.
Plus, they are also available in different system classes and have different exposure times.
Though, one thing to consider is not only the image plate that affects the quality but also the settings of the scanner.
The scanner’s resolution capability is especially important to obtain a clear image.
These are either basic spatial resolution or SRB determines the quality of the image.
Therefore, do not only consider the CR technology but also the scanner and other computed radiography equipment.
First up there is the High-resolution CR image plat scanner for all radiography applications.
It also comes in use for weld testing, aerospace, and profile images.
Other than that, you will require imaging plates.
These are available in different resolutions, standard formats, custom sizes, and shapes.
To see the results, you will need X-ray inspection software.
It evaluates the image, acquires it, generates the report, and also exports or imports data.
The CR technology can provide a histogram adjustment for optimal viewing.
It includes annotation and drawing tools to explain the results.
There are also special analysis tools for instance for wall automated measurement.
It also allows for global data exchange and standardized data exchange using the internet or local network.
Moreover, there is the option of digital archiving and keeping a backup.
The digital magnification gives detailing viewing plus there is image optimization with filters that improve the detection defect detection.
It also includes special analysis tools for instance those for automated wall thickness measurement.
Now that you know the medical equipment of this technology, let’s find out its advantages.
Computed Radiography Advantages and Disadvantages
Advantages
- Low initial cost
CR has initially a low-cost installation.
Hence, it is thought of as a first step in adopting digital imaging technology.
This is because it works like the conventional film technology, hence, you need fewer changes in the workspace and office.
So the initial investment is rather smaller.
- Using different sizes for flexibility
CR can use cassettes of different sizes.
Hence, the detector size can match the procedure.
This increases the flexibility of positioning of the machine for the area of examination.
- Having Single Plate Readers for faster results
Single plate readers are not only compact but also powerful.
Plus they fasten the procedure.
While one plate is under process, you can acquire the next image immediately in a sequence.
- It is compatible with existing conventional systems
Unlike digital radiography, the CR is compatible with the existing systems.
Hence, you do not have to change your workspace a lot either.
However, digital radiography is not compatible with the existing X-ray technology and is also more costly.
- Bedside Examinations
The portable CR technology can have cassette tapes incorporated to provide rapid bedside examination.
Plus also give image presentations in order to get a speedy diagnosis.
- Effective for small clinics
Since the technology utilizes the same workspace as that of the film X-ray, it can be set up in a small or low volume clinic easily.
- Varies the techniques and optimizes imaging quality
Traditional film radiography does not vary the technique except for using a different film type.
However, CR has different imaging plates and also adjustable scanner control parameters for the task.
These allow for image quality optimization and increase productivity.
Other advantages include:
- The plates are reusable
- Plate exposure time is less
- Does not require a dark room or chemical processing
- Stores and shares digital information
Disadvantages
The Phosphor imaging plates require a long time to view the image because they need a longer readout and processing time.
These Phosphor imaging plate detectors are always in the detecting position.
This results in them picking on the background radiation and image noise.
This especially happens if it is in an X-ray room or near it.
There is a small 1 minute delay in scanning the CR plates.
Plus, reading the results requires removing the cassette from the X-ray machine and placing it into a reader.
So this process is labor-intensive where the technician leaves the patient and the work station at each resolution imaging procedure.
Also, the delay may look small but with the patient workload it may not be the best option considering DR only requires 10 seconds.
However, modern systems integrate the plates into the X-ray equipment not requiring the technician to move places.
Though the labor may still come in use for cleaning the cassettes so that it does not lead to noise, keeping the inventory, and maintaining the quality.
That adds up the cost.
The PSP plates in CR have lower efficiency than in DR detectors.
Therefore, to get adequate image resolution, you will require a higher dose of radiation.
Recent developments in CR technology like storage phosphors have improved detecting efficiency though.
While using single plate readers, overexposure results in delay.
This is because the old signals do not erase that quickly.
Hence, you cannot insert a new plate unless the old plate is clear of all residual signals.
Plus CR is rather high maintenance.
There is also a risk of overexposure using a high dose of radiation.
The alternative to CR is Digital Radiography.
It uses a digital X-ray detector to automatically acquire images and transfer them to a computer for viewing the results.
Pros and Cons of Digital Radiography
Cons
- There is not enough positioning flexibility for difficult views. Though, new systems are in development to look over this problem.
- The initial installation costs are significantly higher than CR. Almost 5 times higher. Hence, it limits the equipment to set up where there can be a high return on investment.
- It requires protection from mishandling or dropping.
- You will need a protective cover if there is a need to remove the panel from the bucky tray.
Pros
- High-speed image acquisition
- High-speed workflow for technicians and patients is especially useful in outpatient settings. It takes less than 1 minute for image acquisition.
- The detective quantum efficiency i.e. the X-ray detection efficiency is 60 to 65 percent whereas for CR it is only about 30 percent. Hence, it results in lower patient exposure due to low imaging failures. The results will usually come out accurate.
- Better image quality than CR.
- The development of wireless DR detectors will make them portable.
Comparing computed radiography vs digital radiography you have:
| CR | DR |
| Low image quality | High Image Quality |
| Labor intensive | All digitalized setup |
| Can handle low patient output | Can handle the high patient workload |
| Overexposure risk high | Overexposure risk low |
| Less efficiency | More efficiency |
| Easy to damage and needs maintenance | Remote servicing is possible |
| The initial investment is low | The initial investment is high |
| Takes time for the final image to viewing | Rapid image viewing |
| Bulky | Compact |
| Flexible Positioning | Hard to get difficult positions |
| Portable | Less Portable yet |
| Can fit with existing installations | Needs new setup |
| Less costly to replace | Costly to replace parts |
| Suits low workflow | Suitable for high workflow |
Finally,
Computed Radiography is one of the emerging diagnosis medical equipment.
If you want to replace classic X-ray films then little investment in CR is the first step.
Get it at our shop here.
