Lecture Notes: Anode Heel Effect

Introduction

• Anode Heel Effect: A phenomenon in x-ray beams where one side is more intense than the other.
  • The x-ray beam is divergent, similar to a triangle.
  • The cathode side is more intense than the anode side.

Explanation

• Intensity Difference:
  • Cathode side of the beam is more intense and penetrative than the anode side.
  • Reason: The anode is angled, causing the anode side beam to be obstructed by the "heel" or corner of the anode.
• Visual Learning:
  • Clover Learning and Rad Tech Bootcamp offer visual representations that are helpful.

Factors Affecting the Anode Heel Effect

• Anode Angle:
  • Smaller anode angle (e.g., 12 degrees) increases the anode heel effect as the heel obstructs more.
  • Larger anode angle reduces the heel effect as it opens up more space.
• SID (Source to Image Distance):
  • Decreasing SID (moving closer) increases the heel effect.
  • More pronounced at shorter distances (40 inches compared to 72 inches).
• Field Size:
  • Larger field size increases the heel effect due to a wider beam and light field.

Practical Application

• Positioning:
  • Use the heel effect to your advantage by positioning thicker parts of the anatomy under the cathode side.
  • Example: For the abdomen, place the pelvis under the cathode as it is denser.
  • For the femur, position the hip end under the cathode.

Conclusion

• Simplifying the concept:
  • Understand what the anode heel effect is and what affects it.
  • Use available resources like Clover Learning for visual aids.

Additional Resources

• Consider watching videos from Clover Learning and Rad Tech Bootcamp for more visual understanding.