1. Radiographic Exposure
Presenter: Dr. Dheeraj Kumar
MRIT, Ph.D. (Radiology and Imaging)
Assistant Professor
Medical Radiology and Imaging Technology
School of Health Sciences, CSJM University, Kanpur

2. Introduction
• Radiographic Exposure in Radiography and Imaging Technology.
• Understanding the fundamentals of radiographic exposure is crucial
for producing high-quality diagnostic images.
• In this presentation, we will delve into the key concepts, factors, and
techniques related to radiographic exposure.
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3. Objectives
• Discuss the importance of radiographic exposure in medical imaging.
• Explain the factors affecting radiographic exposure.
• Explore techniques for optimizing exposure settings.
• Provide tips for reducing patient dose.
• Highlight advancements in exposure technology.
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4. Importance of Radiographic Exposure
• Radiographic exposure is a critical step in the process of medical
imaging. It involves exposing patients to ionizing radiation for the
specific purpose of creating diagnostic images.
• Understanding its importance is crucial:
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5. Image Quality
• Proper radiographic exposure is
essential for obtaining clear and
diagnostically valuable images.
• Inadequate exposure can result in
underexposed images with poor
visibility, while excessive exposure
can lead to overexposed images with
loss of detail.
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6. • Diagnostic Accuracy: Radiologists rely on the quality of these images to
make accurate diagnoses. Suboptimal exposure can lead to misdiagnosis,
delayed treatment, or the need for repeat imaging, which increases both
patient radiation dose and healthcare costs.
• Patient Care: Minimizing patient radiation exposure while maintaining
diagnostic image quality is a fundamental principle of radiography.
Achieving this balance requires a thorough understanding of the factors
influencing radiographic exposure.
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7. Factors Affecting Radiographic Exposure
• Several factors influence
radiographic exposure
settings, and radiologic
technologists must
consider them when
producing diagnostic
images:
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8. kVp (Peak Kilovoltage)
• The peak kilovoltage controls the quality or
penetrating ability of the x-ray beam.
• It affects image contrast, with higher kVp
values resulting in lower contrast and vice
versa.
• Proper kVp selection is vital for different
imaging studies and body parts.
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9. mAs (Milliampere-Seconds)
• The milliampere-seconds control the
quantity or number of x-rays produced.
Adjusting mAs affects image brightness
and noise.
• Higher mAs values increase image
brightness but may lead to increased
patient dose.
• Radiographers must balance mAs with
kVp for optimal image quality.
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10. Source-to-Image Distance (SID)
• Source-to-Image Distance
(SID) is the distance between
the x-ray tube and the image
receptor (usually the patient or
a detector).
• It plays a significant role in
radiography:
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11. • Image Magnification: A
shorter SID results in image
magnification, while a longer
SID reduces magnification. A
longer SID is generally
preferred to minimize
distortion and maintain image
accuracy.
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12. • Image Sharpness: Longer SID
settings enhance image sharpness by
reducing the effects of focal spot blur.
• Exposure Intensity: As SID
increases, exposure intensity
decreases. Radiographers must adjust
mAs to compensate for the reduction
in exposure intensity when using a
longer SID.
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13. Patient Anatomy and Thickness
Patient anatomy and
tissue thickness vary
widely, and these
differences have a
significant impact
on radiographic
exposure:
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14. • Variability in Anatomy: Different body parts and
anatomical structures require varying exposure parameters.
For instance, a chest radiograph requires different settings
than an abdominal one.
• Tissue Thickness: The thickness of the patient's tissues
affects the amount of radiation required to produce a
diagnostic image. Thicker tissues may necessitate higher
mAs settings for adequate penetration.
• Pediatric Imaging: Children have smaller body sizes and
different tissue densities than adults, which requires
specialized techniques and considerations for dose
reduction.
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15. Grids
• Grids are used to reduce scatter
radiation, which can degrade image
contrast.
• They are placed between the patient
and the image receptor and consist of
lead strips aligned to allow primary
radiation to pass while absorbing
scattered radiation.
• Grid ratios and focal range play a role
in exposure optimization.
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16. Scatter Radiation
• Scatter radiation results from
interactions between x-rays and patient
tissues.
• It can reduce image contrast and
increase patient dose.
• Proper grid use and collimation help
mitigate the effects of scatter radiation.
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17. Grid Selection
• Choosing the appropriate
grid ratio depends on factors
like patient thickness and the
body part being imaged.
Radiographers must also
align the grid properly to
avoid grid cutoff.
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18. Filtration
• Filtration is the process of removing low-energy x-rays from the
primary beam. This is accomplished by placing a filter, often made of
aluminum, in the path of the x-ray beam.
• The purpose of filtration is twofold: to reduce patient radiation dose
and to improve image quality.
• By removing low-energy x-rays, filtration reduces unnecessary
radiation exposure to the patient's tissues, particularly the skin and
superficial structures.
• It also results in a "harder" x-ray beam, which contributes to better
image contrast.
• Radiographers must ensure that the appropriate filter is selected based
on the clinical context and the energy spectrum of the x-ray tube.
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19. Collimation
• Collimation involves restricting the x-ray beam
to the specific area of interest, thereby
minimizing unnecessary exposure to
surrounding tissues.
• The collimator is a device that shapes the x-ray
beam to match the size and shape of the image
receptor and the anatomy being examined.
• Proper collimation reduces patient dose and
helps produce sharper images with less scatter
radiation.
• Radiographers should follow guidelines for
collimation set by regulatory bodies and
healthcare institutions.
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20. Beam Restricting Devices
• Beam restricting devices are essential tools for
controlling the x-ray beam and optimizing radiographic
exposure:
• Types of Beam Restricting Devices:
• Aperture Diaphragms: These devices are adjustable
collimators that limit the size of the x-ray field, ensuring that
only the area of clinical interest is irradiated.
• Beam Collimators: These devices help shape the x-ray beam
into a specific size and shape, typically matching the
dimensions of the image receptor.
• Cone or Cylinder Collimators: These devices are used for
specific exams, such as dental radiography, to focus the x-ray
beam accurately.
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21. Benefits of Beam Restricting Devices
• They prevent unnecessary radiation exposure to adjacent tissues and
organs.
• They improve image quality by reducing scatter radiation.
• Radiographers must verify that beam restricting devices are
functioning correctly and use them effectively for each patient
examination.
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22. Techniques for Optimizing Exposure
• Radiologic technologists employ various
techniques to optimize radiographic
exposure:
• Automatic Exposure Control (AEC)
Systems:
• AEC systems automatically adjust exposure
factors based on the amount of radiation
received by the image receptor. They ensure
consistent image quality while minimizing
patient dose.
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23. • Exposure Charts and Technique Charts:
• These charts provide guidelines for selecting
exposure factors (kVp, mAs) based on the body
part, patient size, and imaging modality. They
serve as valuable references for radiographers.
• Exposure Indicator Systems (S-Number):
• Some digital radiography systems display an
exposure indicator (S-number) on the image to
indicate the image receptor's exposure.
Radiographers can use this information to assess
and adjust exposure settings.
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24. • Image Receptor Selection (CR vs. DR):
• The choice between computed radiography (CR) and digital radiography (DR)
systems affects exposure techniques. DR systems generally offer faster image
acquisition and may require different exposure settings.
• Repeating Exposures When Necessary:
• If an image is of insufficient quality due to factors such as motion artifacts,
exposure errors, or positioning errors, radiographers may need to repeat the
exposure to ensure diagnostic value.
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25. Reducing Patient Dose
• Reducing patient dose is a fundamental
principle in radiography:
• ALARA (As Low As Reasonably
Achievable):
• ALARA is a radiation safety principle aimed at
minimizing radiation exposure while still
achieving the necessary diagnostic information.
• Radiologic technologists should always strive to
keep patient doses as low as reasonably
achievable while maintaining image quality.
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26. Shielding and Protective Measures
• Lead aprons and thyroid shields
are used to protect patients from
unnecessary radiation exposure
during x-ray examinations.
• Shielding is especially important
for pregnant patients to protect the
developing fetus.
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27. Proper Patient Positioning
• Accurate positioning of the
patient and the x-ray equipment
helps minimize the need for
repeat exposures. Proper
alignment ensures that the x-ray
beam is directed precisely
where needed.
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28. Advancements in Exposure Technology
The field of radiography is continuously
evolving, and exposure technology has seen
significant advancements:
Digital Radiography (DR) and Computed
Radiography (CR):
• Transitioning from film-based radiography
to digital technologies has improved image
quality, reduced radiation exposure, and
enhanced workflow efficiency.
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29. • Improved Image Processing Algorithms:
• Modern imaging systems incorporate sophisticated image processing algorithms that
enhance image quality and help radiologists make more accurate diagnoses.
• Dose Reduction Technologies (e.g., Pulsed Fluoroscopy):
• Specialized fluoroscopy modes, such as pulsed fluoroscopy, reduce radiation dose
while maintaining real-time imaging capabilities.
• AI-Based Exposure Optimization:
• Artificial intelligence (AI) is being used to assist radiographers in selecting optimal
exposure settings by analyzing patient anatomy and other factors in real time.
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30. Conclusion
• Radiographic exposure is a fundamental aspect of medical imaging.
• Understanding the factors affecting exposure and employing proper
techniques are essential for producing high-quality diagnostic images
while minimizing patient dose.
• Staying updated with technological advancements is crucial for a
successful career in Radiography and Imaging Technology.
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31. Questions?
Open the floor for questions and discussions.
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32. References
• Bushong, S. C. (2016). Radiologic Science for Technologists: Physics, Biology, and Protection.
Elsevier Health Sciences.
• Carlton, R. R., & Adler, A. M. (2017). Principles of Radiographic Imaging: An Art and A Science.
Cengage Learning.
• Fauber, T. L. (2016). Radiographic Imaging and Exposure. Elsevier Health Sciences.
• Fosbinder, A. M. (2018). Radiography PREP Program Review and Exam Preparation (8th ed.).
Lippincott Williams & Wilkins.
• Järvinen, H., & Syväoja, S. (Eds.). (2019). Radiography in Modern Industry (Vol. 1):
Instrumentation and Modern Diagnostic Methods. Springer.
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33. Thank You
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