5 keys for Digital Radiography

Computed Radiography (CR) and Direct Radiography (DR) are now the standard imaging technologies in many hospitals and imaging centers. These digital systems mark a significant evolution in the field of medical imaging. X-ray technicians must grasp several critical concepts to effectively utilize these technologies. Familiarity with the functionalities, advantages, and specific operational aspects of both CR and DR systems is essential for maximizing image quality and ensuring patient safety. Each system has unique applications and demands specific skills and knowledge for effective management. Learn more about the capabilities and applications of digital radiography systems here.

 

1. Digital Vs. Film: Know the Difference

While film radiography has evolved significantly over the years with advancements such as high-speed film and rare earth screens, digital radiography systems, including Computed Radiography (CR) and Direct Radiography (DR), have become the standard in modern medical imaging.

Film Radiography Advancements

• High-speed film
• Rare earth screens

Digital Radiography Systems

• Computed Radiography (CR): Utilizes digital cassettes that are portable and capable of holding a latent image.
• Direct Radiography (DR): Captures images directly onto a plate and facilitates immediate image transfer.

Benefits of Digital X-Ray Systems

The shift to digital x-ray systems offers numerous radiation protection benefits compared to traditional film.

“Modern digital receptors are more sensitive than their film counterparts, which allows for reduced mAs settings on technique charts, thereby decreasing patient exposure.”

• Reduced mAs settings due to increased sensitivity of digital receptors.
• Enhanced imaging capabilities and processing speed.
• Significantly reduced likelihood of needing repeat exams.

These benefits not only improve the efficiency and effectiveness of medical imaging but also contribute to minimizing patient exposure to radiation. For more insights into radiation protection, visit our Radiation Protection Resources page.

Explore more about modern radiography techniques and continuing education opportunities at CE4RT.

Advantages of Digital Radiography Systems

• • • Higher Image Quality:The images produced by digital radiography systems are generally of higher clarity and quality than those produced by traditional film radiography. This enhanced image quality is crucial for accurate diagnosis and improved patient outcomes.
    • Post-Processing Capabilities:Digital images offer significant advantages in terms of post-processing capabilities. They can be easily edited and enhanced using various viewing tools such as inversion, zooming, and other adjustments. These enhancements allow medical professionals to examine the subject from multiple angles and perspectives based on a single exposure, without altering the original diagnostic integrity of the image. All modifications are reversible, ensuring that the base image remains unchanged for accurate review and comparison.
    • Reliability of Data Storage:One of the major advantages of digital imaging systems is the reliability of data storage. When properly archived, digital images can be preserved indefinitely without degradation. This ensures that patient images are accessible whenever needed, supporting ongoing and future medical care regardless of the patient’s current admission status.
    • Faster Processing and Delivery:The processing and delivery of digital images are significantly faster compared to traditional film-based methods. This expedited workflow streamlines clinical operations and facilitates quicker diagnoses, which can greatly enhance the effectiveness of treatment and improve patient outcomes. Early detection made possible by the speed of digital imaging can be pivotal in the management and resolution of health issues.
    • Reduced Technical Issues:Film-based radiography can be fraught with mechanical and chemical processing issues. Processor rollers are prone to breaking, and chemical baths can suffer from inconsistent temperatures and concentrations if not maintained correctly. In contrast, digital radiography systems typically experience fewer technical issues, as most problems that do arise are due to human error rather than mechanical failure. This reliability enhances workflow efficiency and image quality.
    • Automatic Exposure Controls:Many digital radiography systems are equipped with automatic exposure controls. These controls help mitigate the risk of incorrect exposure settings, ensuring optimal image quality and reducing the likelihood of needing repeat exposures. This feature not only improves patient safety by minimizing unnecessary radiation exposure but also enhances the diagnostic accuracy of radiographic assessments.
    • Cost and Accessibility:While digital radiography systems present cost advantages for large-scale imaging centers over the long term, the initial costs and maintenance of a film-based system may still be more economical for facilities with low imaging volumes. The investment in staff and infrastructure to support and maintain the computer systems necessary for digital radiography can be substantial. However, this concern has diminished significantly in recent years, as most individuals now possess basic computer skills, making the transition to digital systems smoother and more feasible across a wider range of healthcare settings.
    • Legacy of Analog Training:Many experienced professionals argue that the most skilled digital radiographers are those who originally trained using analog systems. This perspective suggests that techs trained on analog systems develop a strong foundation in radiographic techniques, relying more on their own expertise and precision than on advanced equipment capabilities. As a result, they often transition effectively to digital systems, bringing a high level of skill and attention to detail that enhances image quality. Conversely, the newer generation of radiologic technologists, who are trained exclusively on digital equipment, might miss experiencing certain traditional aspects of the field, such as the distinctive smell of developer in a darkroom.

For more insights into the benefits and challenges of digital radiography, visit our Radiologic Technology Resources page.

Explore continuing education opportunities in radiography at CE4RT.

2. Follow the CR / DR Checklist

Computed Radiography (CR) and Direct Radiography (DR) are pivotal in modern medical imaging, significantly contributing to man-made background radiation. Radiologic technologists play a crucial role in safeguarding public health by adhering to best practices during digital radiography exams.

Best Practices for CR and DR Exams

Below is a checklist inspired by the Image Wisely campaign to ensure optimal performance and safety during CR and DR exams:

• Verify Patient Identity: Confirm the patient’s identity using at least two identifiers.
• Optimize Exposure Settings: Use the lowest possible exposure settings to achieve diagnostic-quality images.
• Positioning Accuracy: Ensure correct patient positioning to avoid repeat exams.
• Image Review: Check images for quality and clarity before completing the exam.
• Data Management: Properly archive and manage digital images to maintain patient records securely.
• Equipment Maintenance: Regularly maintain and calibrate imaging equipment to ensure optimal performance.

Adapting the Checklist for Film Technology

For those still utilizing film technology, it’s important to adapt this checklist to include specific practices related to film:

• Film Selection: Choose the appropriate film type and speed for each exam.
• Development Process: Ensure consistent development by maintaining correct chemical concentrations and temperatures.
• Processor Maintenance: Regularly check and maintain film processors to prevent mechanical issues.

“Radiologic technologists are instrumental in safeguarding public health by adhering to best practices during digital radiography exams.”

For more detailed guidelines on radiologic practices, visit our Radiologic Technology Resources page.

Explore continuing education opportunities in radiography at CE4RT.

As you greet the patient

• • • Confirm the patient’s identity to ensure that the correct individual is receiving the radiographic
      examination.
    • Verify that the imaging order is appropriate and corresponds accurately with the patient’s reported symptoms and medical complaints.
    • Ensure that the examination procedure has been thoroughly explained to the patient and, if applicable, to their parent or guardian.
    • For female patients, confirm the reproductive status to ensure appropriate precautions are taken to protect reproductive health during the imaging process.

Before you begin

• • • Is the exam information acquired from a modality work list?
    • Have all unnecessary persons been cleared from the room prior to exposure?
    • Is there alignment of the beam and body part and image receptor?
    • Is the signal to image distance (SID) correct?
    • Is a grid needed and appropriately placed?
    • Is the beam properly angled and collimated?
    • Have markers been placed?
    • Is shielding necessary and placed correctly?
    • Have the correct technical factors been selected?
    • Have positioning and breathing instructions been given and understood?

During the exam

• • • Are images processed correctly in the reader?
    • Does the correct exam information appear on the images?
    • Is the exposure index correct for the exam?
    • Is the image masked correctly?
    • Are any digital annotations needed?
    • Is the image processed correctly?
    • Have any necessary notes regarding the exam such as medications been charted?
    • Are all images visible and correct in the diagnostic viewing system?

3. Watch Exposure Indicators

When operating Computed Radiography (CR) or Direct Radiography (DR) systems, it is crucial to monitor the exposure indicators. These indicators provide essential feedback by displaying the relative exposure levels received at the image receptor. The displayed values reflect the digital receptor’s efficiency and sensitivity, playing a critical role in assessing the quality of the radiographic technique and ensuring patient safety.

Importance of Exposure Indicators

• Verification of Exposure Factors: Exposure indicators verify whether appropriate exposure factors have been selected, which is essential for producing high-quality images while ensuring patient safety.
• Learning Curve for Technologists: Understanding the nuances of digital image acquisition, processing, and display requires training and experience.

“Without an exposure indicator, it is impossible to verify whether the appropriate exposure factors have been selected, which is essential for producing high-quality images while ensuring patient safety.”

Challenges in Digital Radiography

A significant challenge in digital radiography is the variability in methods used by manufacturers to determine and report exposure indicators. These differences can include:

• Terminology
• Units
• Mathematical formulas
• Calibration conditions

Such inconsistencies can lead to confusion among technologists, radiologists, and physicists, especially when operating systems from multiple vendors. Adequate training on the specific unit in use is essential to prevent errors and discrepancies in radiographic outcomes.

Exposure Indicators by Manufacturer

• Fuji (Japan): Utilizes a sensitivity number (S), reflecting the “speed class” concept familiar to technologists with film-screen radiography experience.
• Carestream (New York): Uses an “exposure index” to denote its exposure indicator, reflecting the average pixel value observed within the clinical region of interest.
• Agfa (Belgium): Employs a CR exposure indicator known as lgM, calculating the logarithm of the median exposure value, focusing on a specific region of interest to assess exposure levels.

Despite advancements, many manufacturers of Direct Radiography (DR) systems were initially slow to develop comprehensive exposure indices. These indices are crucial for assessing image quality and ensuring patient safety at the image receptor level.

For more information on radiographic techniques and exposure indicators, visit our Radiologic Technology Resources page.

Explore continuing education opportunities in radiography at CE4RT.

Fuji corporation S Number	Agfa corporation IgM	Kodak/Carestream – Exposure Index	Detector Exposure – Estimate (mR)	Action
> 1000	< 1.45	< 1250	< 0.20	Underexposed: repeat
601-1000	1.45-1.74	1250-1549	0.2-0.3	Underexposed: QC
301-600	1.75-2.04	1550-1849	0.3-0.7	Underexposed: Review
150-300	2.05-2.35	1850-2150	0.7-1.3	Acceptable range
75-149	2.36-2.65	2151-2450	1.3-2.7	Overexposed: Review
50-74	2.66-2.95	2451-2750	2.7-4.0	Overexposed: QC
< 50	> 2.95	>2750	> 4.0	Overexposed: repeat if necessary

Source Image Gently: Using Exposure Indicators To Improve Pediatric Digital Radiography – Abbreviation: QC = quality control.

4. Avoid Dose Creep

Dose creep refers to the gradual, unintentional increase in radiation exposure that can occur with digital radiography systems. These systems can process a wide range of exposures into clear images, which can inadvertently lead to higher doses being used than necessary.

Understanding Dose Creep

In digital radiography, immediate feedback alerting technologists to incorrect exposures is often absent. Both DR (Direct Radiography) and CR (Computed Radiography) systems are highly effective at compensating for suboptimal techniques, which can lead to a problematic issue known as ‘dose creep.’

“Digital systems can mask exposure errors, resulting in gradually increasing radiation doses without noticeable degradation in image quality.”

Comparing Digital and Analog Radiography

In contrast, traditional analog screen-film radiography involves:

• Fixed film speed
• Consistent processor controls

These require precise exposure settings, where any deviation could result in images that are too light (underexposed) or too dark (overexposed).

Preventing Dose Creep

It is crucial for technologists to monitor and adjust their practices to prevent dose creep. Here are some best practices:

• Regularly review exposure settings
• Utilize exposure indicators
• Ensure proper training on digital systems

By adhering to these practices, technologists can maintain both image quality and patient safety, minimizing unnecessary radiation exposure.

Understanding Dose Creep in Digital Imaging

In digital imaging, immediate feedback that alerts technologists to incorrect exposures is often absent. This can lead to a problematic issue known as ‘dose creep.’

Compensation for Suboptimal Technique

Both DR (Direct Radiography) and CR (Computed Radiography) systems are highly effective at compensating for suboptimal technique. This flexibility, while beneficial, can inadvertently result in gradually increasing radiation doses without noticeable degradation in image quality.

“The flexibility of digital processing can mask exposure errors, leading to dose creep, especially in CR systems without automatic exposure controls.”

Challenges with CR Systems

Dose creep occurs particularly in CR systems that lack automatic exposure controls. The ability of digital processing to compensate for exposure errors can result in higher radiation doses being used than are actually necessary.

Importance of Vigilance

This underscores the importance of vigilance and strict adherence to established exposure guidelines. By doing so, technologists can prevent unnecessary radiation exposure to patients.

Best Practices to Prevent Dose Creep

• Regularly review and adjust exposure settings
• Utilize exposure indicators effectively
• Ensure thorough training on digital systems
• Adhere strictly to established exposure guidelines

 

The Flexibility and Risks of Digital Detector Systems

Digital detector systems have the capability to produce high-quality radiographic images even in cases of significant overexposure or underexposure. This advanced technology optimizes images for display on soft copy monitors or hard copy film, maintaining excellent image quality across a wide range of exposure levels.

Advanced Processing Abilities

Digital technology’s advanced processing abilities enable it to handle varied exposure levels:

• Compensates for underexposures by up to 100%
• Compensates for overexposures by more than 500%

“Digital image processing can effectively adjust for a wide range of exposure levels, ensuring image clarity.”

The Risk of Dose Creep

This robust flexibility, while beneficial for ensuring image clarity, can inadvertently encourage less precise exposure practices. Known as dose creep, this issue can occur if exposure levels are not carefully monitored.

Preventing Dose Creep

To avoid dose creep, technologists should:

• Regularly review exposure settings
• Utilize exposure indicators effectively
• Maintain strict adherence to established exposure guidelines
• Ensure thorough training on the specific digital systems in use

By following these practices, technologists can maintain high-quality imaging while minimizing unnecessary radiation exposure.

The Hidden Risks of Dose Creep

Unfortunately, when dose creep occurs, patients may be subjected to unnecessary radiation exposure without the awareness of medical professionals. It is not uncommon for patients to receive radiation doses three to five times higher than necessary, without detection or complaint from clinical staff.

The Importance of Monitoring and Regulation

This situation underscores the critical need for stringent monitoring and regulation of exposure levels. Ensuring patient safety while maintaining the diagnostic integrity of medical imaging is paramount.

“Patients may receive significantly higher radiation doses without the awareness of medical professionals, highlighting the need for stringent monitoring.”

Key Takeaways

• Unnoticed Overexposure: Dose creep can lead to unnoticed overexposure, putting patients at risk.
• Importance of Vigilance: Regularly monitor and regulate exposure levels to protect patient health.
• Maintaining Diagnostic Integrity: Balance radiation dose with the need for high-quality diagnostic images.

The Risks of Dose Creep in Medical Imaging

Dose creep often occurs because underexposed images may appear poor or unusable, while overexposed images can still look acceptable or even flawless. This tendency inadvertently encourages technologists to err on the side of overexposure, posing a risk of unnecessary radiation exposure to patients.

Striking the Right Balance

The objective in medical imaging should always be to:

• Obtain Clear and Diagnostic Images: Ensure images are clear and diagnostically useful.
• Minimize Radiation Dose: Keep radiation exposure to the lowest possible level.

“Balancing image quality with minimal radiation exposure is essential to ensure patient safety without compromising diagnostic information.”

Key Takeaways

• Avoid erring on the side of overexposure.
• Maintain stringent monitoring of exposure levels.
• Regularly review and adjust exposure practices.

Using Exposure Indicators to Prevent Dose Creep

To help technologists achieve optimal image quality with minimal radiation exposure, most digital detector systems are equipped with an “exposure indicator.”

How Exposure Indicators Work

The exposure indicator provides crucial feedback by:

• Analyzing Raw Image Data: It assesses the intensity of the raw image data.
• Scaling Adjustments: It determines the adjustments needed for suitable brightness and contrast levels.

“Exposure indicators guide technologists in making informed decisions about exposure settings, helping to prevent overexposure and minimize radiation risks.”

Benefits of Exposure Indicators

Using exposure indicators allows technologists to:

• Ensure optimal image quality.
• Minimize patient radiation exposure.
• Maintain diagnostic integrity.

5. Collimate

It is fundamental, though worth emphasizing, that radiographers must meticulously employ collimation to the specific anatomical area of interest during examinations. Proper collimation is crucial for minimizing patient exposure to radiation and ensuring accurate processing of the digital image data.

The Importance of Collimation

Proper collimation helps to:

• Reduce Scatter Radiation: By limiting the area exposed to radiation, collimation minimizes scatter radiation, which enhances image quality.
• Enhance Image Quality: Reducing scatter radiation helps maintain high image contrast, crucial for diagnostic clarity.
• Minimize Patient Exposure: Effective collimation significantly reduces the amount of the patient’s tissue exposed to radiation, safeguarding their health.

“Careful collimation helps to reduce scatter radiation and enhance image quality, aiding in accurate diagnosis while limiting unnecessary radiation exposure.”

Benefits of Precise Collimation

By effectively limiting the area exposed to radiation through precise collimation, radiographers can:

• Decrease the patient’s overall radiation dose.
• Minimize the amount of scatter radiation that reaches the patient.
• Enhance the quality of radiographic images by reducing excess scatter radiation.

 

Enhancing Radiographic Practices with Collimation

Digital radiography systems come equipped with software that enables electronic masking, also known as collimation. This technology recognizes the borders of the exposed area on the image receptor. Radiographers may sometimes need to manually adjust this electronic masking to ensure it precisely aligns with the exposure field.

Electronic Masking vs. Physical Collimation

While electronic masking, shuttering, or cropping can refine the image after exposure, these methods should not replace the beam restriction provided by physical collimation of the x-ray field size. Proper physical collimation is essential for:

• Controlling Radiation Dose: Ensures precise control of the radiation dose.
• Minimizing Exposure: Reduces exposure to non-targeted areas, ensuring patient safety.
• Enhancing Image Quality: Maintains high image quality by minimizing scatter radiation.

“Proper physical collimation is crucial for directly controlling the radiation dose and minimizing exposure to non-targeted areas.”

Maintaining Image Integrity

Masking should never be used to obscure any part of the anatomy that was within the exposure field at the time of image acquisition. This practice is strongly discouraged due to legal and radiation safety concerns. It is essential to maintain the integrity of the original radiographic image, ensuring all anatomical areas exposed during the procedure are visible for accurate diagnosis and compliance with medical imaging standards.

Key Takeaways

• Use electronic masking to refine images, but not as a substitute for physical collimation.
• Ensure physical collimation is properly applied to control radiation dose and minimize exposure.
• Maintain the integrity of the original radiographic image for accurate diagnosis.

Optimizing Image Quality with Proper Collimation

In digital radiography systems, mathematical algorithms play a crucial role in adjusting image brightness and contrast. However, excessive white space within an image can disrupt these calculations, potentially leading to inaccurate image rendition.

Importance of Precise Collimation

To ensure accurate image quality, it is best practice to:

• Precisely Collimate the X-Ray Beam: Cover only the anatomic area relevant to the diagnostic procedure.
• Utilize Electronic Masking Correctly: Enhance image viewing conditions by clearly showing the actual edges of the exposure field.

“Precise collimation helps document proper exposure and ensures the entire area exposed during the procedure is visible.”

Proper Use of Electronic Masking

When using electronic masking to enhance image viewing:

• Ensure it clearly shows the edges of the exposure field.
• Do not use masking to cover any part of the anatomy within the exposure field at the time of acquisition.
• Avoid obscuring critical diagnostic information.

Maintaining Diagnostic Integrity

Masking should never be used to hide any anatomical areas that were exposed during the procedure. This ensures that no critical diagnostic information is obscured, maintaining the integrity of the radiographic image.

Key Takeaways

• Precisely collimate to the relevant anatomic area.
• Use electronic masking to show the actual exposure field edges.
• Never use masking to obscure parts of the anatomy exposed during the procedure.

 

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FAQs

1. What is the main difference between Computed Radiography (CR) and Digital Radiography (DR)?

The main difference between Computed Radiography (CR) and Digital Radiography (DR) lies in how they capture and process images. CR uses photostimulable phosphor plates that need to be processed in a CR reader to convert the image into a digital format, whereas DR uses flat-panel detectors that directly capture and digitize the image, allowing for immediate viewing and faster workflow.

2. How does a CR system work in capturing X-ray images?

In a CR system, an X-ray image is captured on a photostimulable phosphor plate. After exposure, the plate is inserted into a CR reader, where it is scanned with a laser. The laser stimulates the phosphor, causing it to emit light proportional to the X-ray exposure. This light is then converted into a digital image by a photomultiplier and processed for viewing and analysis.

3. What are the advantages of using Digital Radiography (DR) over Computed Radiography (CR)?

Digital Radiography (DR) offers several advantages over Computed Radiography (CR), including:

• • • Faster image acquisition and processing, leading to improved workflow efficiency.
    • Higher image quality with better spatial resolution and contrast.
    • Immediate image availability, reducing patient wait times and allowing for quicker diagnosis and treatment decisions.
    • Reduced radiation exposure to patients due to more sensitive detectors.
    • Elimination of the need for physical processing and handling of imaging plates.

4. What are the common artifacts seen in CR and how can they be minimized?

Common artifacts in CR include:

• • • Plate reader artifacts: Caused by issues with the CR reader, such as dirt or debris on the rollers. Regular maintenance and cleaning can minimize these artifacts.
    • Phosphor plate artifacts: Scratches, dust, or damage to the phosphor plate can create artifacts. Handling plates carefully and storing them properly can reduce these occurrences.
    • Image processing artifacts: Arising from incorrect image processing parameters. Proper calibration and using appropriate processing algorithms can help minimize these artifacts.

5. How can radiologic technologists ensure optimal image quality in DR systems?

To ensure optimal image quality in DR systems, radiologic technologists should:

• • Regularly calibrate and maintain DR equipment to ensure it is functioning correctly.
  • Use appropriate exposure settings to achieve the best balance between image quality and patient dose.
  • Employ proper positioning and technique to minimize motion artifacts and ensure clear images.
  • Stay updated with training and best practices in DR technology to fully utilize the system’s capabilities.
  • Conduct regular quality control checks to identify and address any issues promptly.