When the selected kVp (kilovolt peak) is too high during an X-ray examination, the resulting image will be overexposed, leading to decreased image contrast and potential harm to the patient.
Understanding kVp
kVp determines the energy level of the X-ray beam, impacting the penetrating power of the radiation. Higher kVp levels mean higher energy X-rays, which can penetrate denser tissues more easily.
Effects of High kVp
- Overexposure: The X-ray beam penetrates the body too easily, resulting in a darker image with less detail.
- Reduced Contrast: The difference between light and dark areas on the image is diminished, making it harder to differentiate between tissues.
- Increased Patient Dose: Higher kVp leads to a higher radiation dose to the patient, increasing the risk of potential long-term health effects.
Practical Implications
- Diagnostic Accuracy: Overexposed images can hinder the ability to accurately diagnose medical conditions.
- Repeat Examinations: If the image quality is inadequate, a repeat examination may be necessary, exposing the patient to additional radiation.
Adjusting kVp
Radiographers adjust kVp based on the patient's anatomy, thickness, and the desired image quality. Selecting the appropriate kVp is crucial for obtaining optimal diagnostic images while minimizing patient dose.
Examples:
- A patient with a thick chest may require a higher kVp to penetrate the dense tissue.
- A patient with a thin hand may require a lower kVp to avoid overexposure.
Conclusion
Using a high kVp can compromise image quality and increase patient radiation exposure. Careful selection of kVp is essential for ensuring accurate diagnoses while minimizing patient risk.
