Blog | PatientImage

What Does CR Mean in Radiology?

Written by Chad Hutchison | Nov 1, 2024 7:00:00 AM

The digitization of medical imaging has revolutionized patient care by providing faster, higher-quality images, allowing for more rapid diagnostics and treatment. It also reduces the patient’s exposure to radiation, making it safer than ever before. 

Clinics, hospitals, and medical imaging facilities looking to enter the digital era but not yet able to afford all new equipment can use CR, which offers an affordable solution. 

This article examines CR in radiology, how it works, its main components, and the advantages of switching to it. 

What Is CR in Radiology?

CR stands for computed radiology. It’s a system that produces digital X-ray images of the human body. While it’s computed and produces digital images, it should not be confused with DR (digital radiography), which uses flat panel detectors to create a digital image instantly. 

While these systems also produce digital X-ray images, they do so via an entirely different process. Instead of a flat panel detector that produces instant digital images, these systems utilize an imaging plate that stores information from X-rays passed through the patient. A laser system then scans that imaging plate and converts the data into a digital image. 

Computed radiology may be a bit slower than modern DR systems, but it’s much faster than traditional X-ray film processing. The primary benefit of CR systems is their ability to retrofit a traditional X-ray machine. It allows clinics to switch from film to digital images, allowing a low-cost alternative to digitizing image workflow. 

How Does Computed Radiography Work?

Computed radiography works similarly to other radiographic imaging systems. It uses electromagnetic radiation called X-rays, which are directed through the patient to produce images of the bones and soft tissues based on their varying density. 

Bones are the most dense, so they absorb the most X-rays and appear white, while organs and soft tissues which are less dense allow some to pass through and appear as shades of gray. The contrast in colors enables doctors to gain accurate images of internal structures to aid diagnostics and treatment.

However, instead of detecting X-rays on traditional film, this system uses a photostimulable phosphor (PSP) imaging plate held inside a CR cassette. The PSP detects and stores energy when exposed to X-rays during an X-ray imaging procedure. 

Instead of processing film in a darkroom with chemicals or creating instant digital images like a DR system, the CR cassette is inserted into a reader. The reader has a precision laser system that scans the plate and releases the stored energy as visible light. 

A photomultiplier tube (PMT) detects light and converts it into an electric signal. The signal is then digitized, converting the raw data into detailed digital images. 

These images can now be viewed on-screen, efficiently shared, and securely stored electronically via the Picture Archiving and Communication System (PACS). The advanced software in these systems also allows the images to be further processed, including adjusting the contrast to enhance certain anatomical features to enable the highest diagnostic quality images. 

Finally, once the information has been stored securely, the PSP plate is exposed to intense light, which erases all the residual data and makes it ready to be used again. 

What Are the Components of Computed Radiography?

Computed radiography utilizes five main components. These components can typically be used to retrofit a traditional X-ray machine. 

  1. Radiographic Generator: This device emits radiation to create an image. When the CR is compatible with the existing traditional X-ray machine, it may not need a new radiographic generator and can instead use the existing one. 
  2. Imaging Plates: These replace traditional film plates and include a CR cassette containing reusable photostimulable phosphor (PSP) imaging plates. The PSP plates detect and store X-ray information as it passes through the patient’s body. They can be erased and reused thousands of times. 
  3. Image Reader: Once the PSP plate has been exposed to X-rays, the CR cassette is placed in the image reader, replacing traditional film's darkroom and chemical processing. Here, a laser reader scans the PSP plate, taking about 1-3 minutes, digitizes the image, and transfers it to the workstation for immediate viewing. 
  4. Workstation: Most computed radiography systems use a computer monitor to allow doctors and radiologists to view, analyze, and digitally transfer images. 
  5. Software: These systems use diagnostic imaging software to store, analyze, and manage images. It allows advanced processing to produce better images while streamlining file management compared to traditional systems. 

What Are the Advantages of Computed Radiography?

Image Quality

Compared to traditional X-ray films, CR offers superior image quality. The digital processing allows for adjustments in contrast to enhance the viewing of internal structures without the need for additional images, facilitating better diagnostic speed and accuracy.

Lower Radiation Doses

The digital sensors in computed radiography systems are more sensitive to X-rays than traditional film models. This means that less radiation is needed to produce diagnostic-quality images. Furthermore, the ability to digitally enhance the images with the advanced software also reduces the need for additional views or retakes, further reducing radiation exposure. 

Environmental Considerations

Since digitization eliminates the need for chemical processing, fewer toxic chemicals are used and disposed of, reducing your clinic’s environmental footprint. Furthermore, since the PSP plates can be reused thousands of times, the use of consumables is also reduced. 

Low Cost

Since the CR system can be used to retrofit a traditional X-ray machine, it is a lower-cost alternative for those looking to replace film with digital imaging. It also saves money associated with the cost of films, physical storage, and disposal. 

Streamline Workflow 

Since CR requires less processing time than traditional X-ray films, this streamlines processes and improves workflow efficiency. Instead of spending time processing films, staff can focus on patient care and more quickly move patients on to treatment while they get to the next patient in need. 

Final Thoughts

Computed radiography (CR) offers a cost-effective solution for clinics wanting to transition from traditional film to digital imaging but lack the budget to purchase an entire new digital system. Instead, their traditional X-ray machine can be retrofitted to utilize CR technology. 

Utilizing photostimulable phosphor plates improves image quality and reduces processing time. It also reduces radiation exposure for patients and minimizes the clinic’s environmental footprint associated with traditional films and chemical processing. 

As healthcare continues to evolve and embrace the digital age, adopting CR can streamline processes and improve patient care. If you are considering an upgrade, contact PatientImage to discuss imaging solutions that fit your needs and budget.