Virtual Wedge of Siemens

The use of wedge filters in radiotherapy to produce dose gradients across the beam profile is widespread.

Traditionally this is done using physical wedges made of metallic material shaped in such a way so as to produce graduated attenuation across the radiation beam.

Controlling the movement of one of the collimator jaws and the delivered dose rate throughout irradiation can produce similar beam profiles.

The Siemens Virtual Wedge™ uses this philosophy to replace physical wedge filters.

Reference:

Behavior of the Siemens Virtual Wedge™ following an interruption to beam delivery. N. D. Richmond* and C. P. Walker