Embedded Files
Kathryn Crumpler and Mackenzie Hosley
RADS 3300 Website Project
Interactive worksheet QR code:
Mission of the project
Mission of the project
Measure how the Anode Heel Effect changes the exposure intensity across the image receptor and evaluate how the SID affects the visibility of the image.
Hypothesis:
Hypothesis:
The anode heel effect will cause a reduced intensity on the anode side due to absorption of the photons on the beveled anode angle. A longer SID and larger anode angle will reduce this effect.
Line Focus Principle
Line Focus Principle
Anode Heel Effect
Anode Heel Effect
The beam hits the angled anode target and creates the actual focal spot. The actual focal spot hits the angled anode target and produces the effective focal spot. We usually want a steeper anode angle to keep the effective focal spot small.
When the beam hits the angled anode target it's projected down toward the patient, but due to the anode heel some of the x-ray beam is absorbed. This causes the exposure to be less intense on the anode side of the image receptor. We want a larger anode angle and an increased SID to decrease this effect.
Experiment:
Experiment:
Materials: X-ray tube with anode angle, image receptor, marker, ruler or tape measure
Set Up: Position x-ray tube directly above the image receptor, confirm the location of the anode and cathode ends of the x-ray tube.
Procedures: Take an image of the IR at 20 SID with low exposure factors to see the anode heel effect.
Overall, we conducted exposures using different SIDs and measured the exposure variation across the image receptor. Images were analyzed to determine intensity differences between the anode and cathode sides.
Technique Chart:
Technique Chart:
Image #1 - SID of 20 ", KVP of 41, and mAs of .2
The anode side of the image receptor is lighter due to some of the x-ray photons being absorbed by the anode heel.
Exposure taken at 20" SID with 41 kVp and .2 mAs
The cathode side of the image receptor is darker due to more exposure or penetration from the x-ray beam.
Results and Analysis:
Results and Analysis:
Analyzed the different exposure intensities on the image receptor from the anode side to the cathode side
Recorded results.
Visualized the exposure intensity across the image
Compared the test images with the first image to examine the impact of the anode heel effect.
We came to the conclusion that at a 20" SID with 41 kVp and 0.2 mAs, the image receptor showed noticeable variation in exposure. The anode side appeared lighter due to absorption of photons by the anode heel, while the cathode side appeared darker due to greater x-ray penetration and intensity.
Conclusion and Reflection:
Conclusion and Reflection:
Conclusion: Our findings supported the hypothesis that the anode heel effect leads to decreased exposure on the anode side on the image.
Reflection: This experiment helped us better understand the practical implications of tube geometry and positioning. Adjusting SID and being aware of the beam angle are crucial for achieving an optimal image.
Visual Analogy: (A way to remember the Anode heel effect)
Visual Analogy: (A way to remember the Anode heel effect)
Think of it like a flashlight hitting the wall at an angle.
On the far end, the light will be weaker. This represents the anode side.
On the near end, it will be brighter-- this is the cathode side.
Thicker body parts (such as the abdomen) will go under the cathode side to get better exposure!
Interactive Questions:
Interactive Questions:
What will happen when the anode angle increases?
The heel effect will be less pronounced and the effective focal spot will increase. Why? Because more x-rays are absorbed in the anode due to the steeper angle
What will increase the anode heel effect?
A decreased SID increases the anode heel effect. Why? Because the beam divergence is greater at short distances, so the variation of beam intensity from the anode to the cathode side will be more noticeable.
What is the anode heel effect caused by?
The heel effect is caused by absorption within the anode. Why? Because x-rays emitted toward the anode side will travel through more of the anode material and are partially absorbed, which will reduce the intensity.
References and videos:
References and videos:
Meaghan Piretti: Anode Heel Effect
Piretti, M. (n.d.). Anode Heel Effect. YouTube. https://www.youtube.com/watch?v=eV-chCCM-Zw&list=PLHsh2H5GafloB8InULShAcSkqDLQy5R4h&index=2
Clover Learning
Anode Heel Effect. Clover Learning. (n.d.). https://app.cloverlearning.com/learn/courses/radiography-image-production/xray-tube-and-components/anode-heel-effect
Radiopaedia
Wilczek, M. (Ed.). (2025, July 27). Anode Heel Effect. Radiopaedia. https://radiopaedia.org/articles/anode-heel-effect?lang=us
Bushong
Bushong, S. C. (2021). RADIOLOGIC SCIENCE FOR TECHNOLOGISTS : Physics, Biology, and Protection. (12th ed.). Elsevier Mosby. (Pages 118-119)
Link to watch the presentation of this project:
https://www.loom.com/share/4a065d656df2412d966f1770ef09ac9c
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