Introduction to Digital Radiography Flashcards
What are the primary differences between film-based radiography and digital radiography (DR)?
Film-based radiography uses films, darkrooms, and chemical processing to produce images, which cannot be manipulated after recording.
Digital radiography (DR) employs technologies like photostimulable storage phosphors, amorphous selenium/silicon, CCD, or MOS-FET to produce digital images, which can be processed, displayed, and archived digitally.
What are the main components used in film-based radiography for image formation?
Film-based radiography uses films and intensifying screens that emit light when struck by X-rays. The light exposes the film proportionally to the X-ray intensity, and the image is developed using chemicals in a darkroom.
Why is film-based radiography considered obsolete in developed countries?
Due to its limitations, such as the inability to manipulate images after recording and the need for chemical processing. It has been replaced by more efficient digital imaging systems.
Define digital imaging and mention some modern imaging modalities.
Digital imaging is any image acquisition process producing electronic images viewable and manipulatable on a computer.
Examples include CR, DDR, Ultrasound (US), CT, MRI, Nuclear Medicine (NM), and Radiotherapy (RTx)
What technological advancements led to the development of digital imaging?
1970s: Introduction of the CT scanner by Godfrey Hounsfield, coupling computers with imaging devices.
1980s: Introduction of Computed Radiography (CR).
2007: Introduction of Direct Digital Radiography (DDR)
What does the National Radiology Policy emphasize regarding the transition from film-based to digital radiography?
- Infrastructure and equipment guidelines to support the shift to digital radiography.
- Alignment of training institution curricula with health sector policies.
What are multislice imaging modalities, and what distinguishes them?
- Multislice modalities generate complex raw-data imaging sets, stacking single images into multiple series.
- They require detailed post-acquisition processing software for reprocessing (e.g., Tomography, MRI).
Describe the image formation and workflow in film-based radiography.
- Film is placed between intensifying screens that emit light upon X-ray exposure.
- The exposed film is processed with chemicals in a darkroom.
- The developed image is interpreted by a radiologist and archived in a filing room.
How are imaging modalities categorized based on their output?
- Single-image modalities: Produce standalone images (e.g., CR, DDR, Mammography).
- Multislice modalities: Stack single images into multiple series (e.g., CT, MRI).
- Hybrid modalities: Combine imaging outputs for advanced visualization.
What are the benefits of digital radiography over film-based systems?
Faster image acquisition and processing.
Easy manipulation and enhancement of images.
Simplified storage and sharing through digital networks.
What are hybrid imaging modalities?
Hybrid modalities combine two imaging techniques to form a new method, producing stacked single images that are later fused for display and interpretation.
Can you give examples of hybrid imaging modalities?
MRI-PET
Ultrasound-MRI
MRI-CT
What are the advantages of hybrid imaging modalities?
- Provide both structural and functional information in the same image.
- Improve diagnostic confidence when one modality alone is insufficient.
- Enable precise monitoring of interventional procedures.
- Reduce radiation exposure, e.g., using dynamic ultrasound after obtaining a CT map.
What is the role of the computer in a digital imaging system?
The computer system is coupled with medical imaging devices to capture, process, and display diagnostic information for radiodiagnosis.
