Introduction to Digital Radiography

Introduction to Digital Radiography

• Digital radiography (DR) involves using electronic detectors instead of film to capture x-ray images.
• Images are stored digitally, enabling easier manipulation and sharing.
• DR offers advantages, but also concerns such as higher upfront costs and possible sensor damage.

Objectives of the Lecture

• Students should be able to differentiate analog and digital images.
• Students should be able to describe various digital radiographic (DR) systems.
• Students should compare various DR systems (e.g., PSP, CCD, CMOS).
• Students should be able to list applications of DR in dentistry.

Image Receptors

• Dental images are created when an object is exposed to x-radiation.
• Attenuated beams are received by image receptors.
• Image receptors include films (analog), sensors/detectors, and image plates (filmless digital).

What is a Digital Image?

• A digital image is saved in a computer's memory.
• It's a representation of a real image as a set of numbers.
• Images are composed of pixels arranged in a matrix.
• Each pixel has a gray shade (color) and a specific position.

Digitization

• Digitization is any modality or method that creates an image viewable and storable on a computer.

Analog vs. Digital Images

• Analog images use dental films, showing continuous gray shades between black and white.
• Digital images use sensors, producing discrete gray shades (pixels).
• Digital images are numeric and discrete unlike analog images that use continuous tone.

Intraoral Digital Imaging

• Analog images are captured and displayed on conventional dental film.
• Digital images are captured by sensors and displayed on a computer monitor.

Advantages of Digitization

• Digital image enhancement is possible.
• Images can be shared with other specialists (teleradiography).
• Processing is faster.

Disadvantages of Digitization

• Longer processing times may still exist in some cases.
• Films are still used in combination with DR.
• No reduction in overall radiation dose in all DR systems.

DR Systems

• DR systems include direct (CCD, CMOS, CID) and indirect (PSP) systems.
• Direct systems convert x-ray energy directly to an electronic signal.
• Indirect systems use a photostimulable phosphor plate to store x-ray energy, converting it to light then an electronic signal.

Indirect Digital Radiography

• Indirect DR systems digitize analog images using scanners or cameras.
• The scanned analog image is converted to a digital image.

Direct Digital Radiography

• Direct digital radiography uses sensors that convert x-rays directly into digital signals.
• This approach typically provides immediate image viewing and eliminates the step of processing.

CCD and CMOS

• CCD (Charged Coupled Device): faster and better image resolution than PSP.
• CMOS (Complementary Metal-Oxide-Semiconductor): less expensive and less bulky than CCD.

PSP (Photostimulable Phosphor)

• PSP plates store x-ray energy electronically, releasing it as light for digitization.
• PSP plates are re-usable.
• PSP systems typically involve a scanning process.

Digora PSP System

• Digora is a common type of PSP system.
• It uses a reusable photostimulable phosphor imaging plate.
• The plates contain a layer of barium fluorohalide phosphor, which captures the x-ray energy.

Methods of Scanning Phosphor Plates

• Rotating plate scanning
• Stationary plate scanning

Pros & Facilities of Digital Radiography

• Time-saving compared to conventional imaging methods.
• Reduced exposure times (lower radiation dose).
• Enhanced image presentation and understanding to improve patient education.
• Digital Storage, Archiving, and Recall (SAR).
• Image compression for storage space efficiency.

Teleradiography

• Transmission of images (x-rays, CT, MRI) for consultation and sharing among specialists.

Environmental Friendliness

• No use of chemicals; reusable sensors; less space requirements (no darkrooms).

Fewer Files Cluttering

• Digital storage reduces the physical volume of radiographic files.

Sensor Sizes

• Sensors are available in various sizes to accommodate diverse imaging needs.

Image Enhancement

• Software can enhance image quality by adjusting brightness and contrast, sharpening, and pseudo-coloring.

Image Manipulation

• Software enables zooming, measuring, and magnification functionality.
• Software tools aid analysis and problem identification.

Combining Intraoral Radiographic Data

• Integration of intraoral and radiographic data for comprehensive analysis.

Pseudo 3D

Subtraction

• Using sequential radiographic images to analyze changes over time.
• Subtracting the first image from the second highlights changes (such as bone loss).

Quantitative and Qualitative Analysis

• Quantitative analysis produces numeric results for bone changes.
• Qualitative analysis visualizes areas of change on the image.

Geometric Standardization and Exposure Parameters

• Geometric parameters are crucial for accurate radiographic analysis.

Cons & Limitations

• High initial investment: digital systems are more expensive than traditional systems.
• Sensor Thickness: Some patients find direct sensors thicker and uncomfortable.
• Sensor Damage: Cables can be damaged; sensors often cannot be sterilized.
• Resolution: Some digital systems have lower resolution than film systems.
• Software needs: Advanced software is essential for efficient use.

Clinical Application of Digital Radiography in Dentistry

• Digital radiography is applicable to various dental specializations, improving diagnostic accuracy and image handling.

Dental radiographic use of DR in specializations like Prosthodontics, Implantology, and TMJ

• Digital radiography is used for these specific areas in dentistry to enhance the quality and accuracy of information gathering

Radiometric Measurements (Bone Density)

• Using the area tool for analysis; produces mean gray values after surgical intervention for bone density.

Digital Tomography for TMJ and Orthodontics

• Using digital tomography for analyzing temporomandibular joint (TMJ) conditions and other specific areas of the mouth.

Explore the fundamentals of digital radiography (DR) in this quiz. Understand the differences between analog and digital images, learn about various DR systems, and discover the applications of DR in dentistry. Test your knowledge and compare different imaging technologies.