Related Experiment Video
Updated: Oct 27, 2026

Automatic Laser-based Geometry Capture for Finite Element Analysis of Weld Beads
Published on: July 25, 2025
A three-dimensional algorithm for optimizing beam weights and wedge filters
L Xing1, R J Hamilton, C Pelizzari
1Department of Radiation Oncology, Stanford University, California 94305-5304, USA. lei@reyes.stanford.edu
Abstract:
An essential step towards optimizing and automating radiation therapy treatment planning is to develop an effective algorithm to find the optimal beam weights and wedge filters for a given set of beam directions and modalities. This problem is solved by introducing a variable transformation based on the universal and omni wedge principles. Instead of directly optimizing an objective function with respect to wedge angles and orientations, each field is first decomposed into a superposition of an open field and two orthogonal wedged fields. This transforms the problem of finding J beam weights, wedge angles, and orientations to that of optimizing a system with 3J beam weights (J open beams and 2J nominal wedged beams), where J is the total number of incident beam directions. An iterative algorithm based on a method originally developed for image reconstruction is used to find the 3J beam weights. The technique is applied to a few clinical cases. Treatment plans are improved compared to those obtained through the conventional manual trial and error planning process. In addition, planning time and effort are greatly reduced.
Related Concept Videos
Wedges
Consider using a wedge to lift a heavy slab. Here, the wedge functions by converting the applied force into a much larger force directed almost perpendicular to the initial force. This...
Shearing Stresses in a Beam: Problem Solving
Beams with Symmetric Loadings
The M/EI...
Beams with Unsymmetric Loadings
The first moment-area theorem determines the slope at any point on the beam. This theorem indicates that the change in slope between two points on a beam...
Deflection of a Beam
Singularity functions, described in an earlier lesson, are powerful mathematical tools that represent discontinuities within a function commonly encountered in structural loading...
Design of Prismatic Beams for Bending