What does the wedge angle represent in radiation therapy?

The wedge angle in radiation therapy represents the tilt of the isodose curve with respect to the normal to the central axis at a reference depth. This concept is crucial in treatment planning, as it helps in modifying the dose distribution within the patient's target volume.

When a wedge filter is used in radiation therapy, it alters the way the radiation beam interacts with the tissue, allowing for a more conformal dose delivery to areas requiring different dose distributions. The isodose curves represent lines of equal radiation dose delivered to the patient. The wedge angle indicates how much the isodose curve is shifted or tilted from the central axis, allowing for compensation of irregular treatment areas and improving the targeting of tumors while sparing surrounding healthy tissue.

This understanding of the wedge angle is essential for medical dosimetrists when designing treatment plans to ensure adequate tumor coverage and optimal patient safety.