Computer Assisted Surgical Planning
CREATED: 200701010953 Author: Danny Chen ** Background
- intensity modulated radiation therapy
- delivered using linear accelerator with multi-leaf collimator *** Methods
structure contouring (image segmentation)
** determine position of tumor
beam angle selection
** select a set of angles to cover the whole tumor with sufficient radition without harming healthy tissue
dose calculation and intensity maps
leaf sequencing
** compute a set of apertures to deliver intensity map in minimum time
delivery
** Step and shoot IMRT delivery
- NP hard in general
- special cases ** 2D SLS ** basic 3D SLS
** 2D SLS
- property of collimator, polygon monotone in y-axis
- assume intensitive either 0 or 1 (can be obtained by slcing the 3D problem)
- consider structures such as valley and peaks since they indicate different apertures, due to monotone property
- similar to matching valley and peaks but do not allow crossing
- solve as max flow on a planar graph
** 3D SLS
- restrict height of plateau to be 1
- if intensity less than 10 (usually), basic SLS ~ general SLS *** Method
create delivery options
** may have exponential number of options ** actually only need to compute canonical option! => intervals are not contained