Anode Heal Effect

Includes everything detailed about heel effect . Defination . Explanation . Applications . Uses . Radiography . Physics . X ray tube . Angle . Size distance . Physics .heal effect . Mammography .

1. ANODE HEAL EFFECT PRIYANSH KUMAR SAHU M.Sc. RADIOGRAPHY DMIMS

2. CONTENTS Definition / Introduction Explanation Factors affecting anode heal effect Anode angle Field size Source to image receptor distance Applications and its uses

3. DEFINATION The anode heal effect is a well described phenomena where radiation intensity varies Anode – Cathode axis of the x - ray tube The effect is increasing towards the cathode and decreasing towards the anode . Photons emitted towards the anode side are attenuated more than those emitted towards the cathode . The heal effect can be utilised to reduce dose to radiosensitive organs. The tilted x-ray target causes the heal effect .

4. The x ray radiation generated in the tilted anode travel along the different path lengths undergoing different attenuation causing certain image receptor receives more radiation than others leaving them darker . Electrons interacts at various depths in the target. The anode heal effect is used to optimize the image quality and patient dose .

5. EXPLANATION Anode heal effect can benefit in x ray imaging by aligning the anode – cathode axis parallel to thinner – thicker sections of the patient body Thus equalising the patient exposure to x- rays produce more uniform image . The intensity of the x-rays that are emitted to the `heal’ of the target is reduced because they have longer path through the target and therefore increased absorption. This is the HEAL EFFECT .

6. FACTORS AFFECTING ANODE ANGLE FIELD SIZE SID (SOURCE TO IMAGE RECEPTOR DISTANCE)

7. ANODE ANGLE If the angle of the anode decreases then the anode heel effect increases. But if the angle of the anode increases then the anode heel effect decreases. When the angle of the anode is large the usable x ray photons do not have to travel through as much of the anode material to exit the tube

8. FIELD SIZE Anode heel effect is directly proportional to field size . If we collimate or reduce the field size that will also reduce the heal effect . Or if we increase the field size of the collimator it will increase the heal effect . So, The field will be more uniform at the center in smaller field size.

9. SID (source to image distance) The distance form anode to image receptor influence the heal effect . The SID is inversely proportional to the anode heal effect . If the SID is increased then the heal effect is decreased . But if the SID is decreased then the heal effect is increased

10. APPLICATIONS AND USES Anode heal effect can benefit x ray imaging by aligning the anode – cathode axis parallel to thinner and thicker sections of the patient body . Thus equalising the patient exposre to x rays and produce more uniform image. Anode heal effect is important during the radiography of non uniform anatomical structures. The cathode side at the thicker part of the anatomy provides more uniform radiation exposure of the image .

11. EXAMPLES Radiography of Dorsal and Lumbar spine in which the dorsal spine at anode and lumbar spine is at cahode . Radiography of Humerus in which the shoulder at cathode and elbow is at anode . Radiography of Leg in which the knee is placed at cathode and ankle is placed at anode . For the radiography of the female patients the head is at cathode end and ovaries are at anode end cause they are radiosensitive organs .

12. IN MAMMOGRAPHY Mammography also utilizes the anode heal effect to its advantage by aligning the cathode close to the thoracic wall which is thicker and denser And anode close to the nipple which is thinner .

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