Table of Contents Table of Contents
Previous Page  184 / 1359 Next Page
Information
Show Menu
Previous Page 184 / 1359 Next Page
Page Background

36

Main steps in the OOPS (Object Oriented Pixel

Shadowing) back projection algorithm for head

scatter geometry integrations:

I. Cover scattering surface by a pixel matrix.

II. Set all pixels as scattering.

III. Illuminate the matrix by a light source place

in the calculation point.

IV. Construct the shadow cast on the matrix

from each collimating element (collimator,

MLC, block,…).

V. Combine all shadows (reset shadowed

pixels).

Only visible pixels remains set !

Head scatter fluence calculation

- integration over extended sources

Can not be seen through

the collimators

Can be seen through

the collimators

Calculation point

Collimator

Scatter source