Conventions for wedge filter specifications.

The use of wedge filters in radiation therapy is well established. With the recent increase in the use of megavoltage radiation equipment, there has been a corresponding increase in the use of wedge filters, particularly in the U.S.A. Agreed conventions for specification of wedge field size, wedge angle, wedge isodose normalization, wedge factor and wedge isodose display therefore become increasingly important to both user and manufacturer. The intent of this letter is to suggest that such conventions be adopted.