Biomedical Engineering Reference
In-Depth Information
6. D
ESIGNING A
T
REATMENT
P
LAN
Introduction ........................................................................................111
The Planning Process.........................................................................113
Planning Aims.....................................................................................115
Requirements on the overall treatment .................................................115
Requirements regarding the tumor........................................................116
Requirements regarding the normal tissues ..........................................116
Other requirements................................................................................117
Tradeoffs ...............................................................................................118
Prescription ........................................................................................118
Technical Data ......................................................................................119
Representation of Dose.......................................................................119
4D dose distributions ............................................................................120
2D dose distributions ............................................................................121
3D dose distributions ............................................................................123
1D dose distributions: the dose
volume histogram (DVH) .................125
0D dose and dose-volume statistics .....................................................126
0D measures of biological effect .........................................................128
Plan Assessment
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The Balancing Act................................................128
Organ by organ inspection ....................................................................128
Tumor control........................................................................................129
The missing tissues ...............................................................................129
Combining all the factors ......................................................................130
Plan Comparison................................................................................130
Side-by-side dose distributions .............................................................130
Dose difference display.........................................................................133
Overlaid DVHs......................................................................................133
Comparison of dose statistics and biophysical models.........................134
Combining all the factors ......................................................................135
Post-planning Activities......................................................................135
Simulation of treatment.........................................................................135
Delivery of treatment ............................................................................135
Ongoing patient evaluation ...................................................................136
Documentation and archiving ...............................................................137
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I
NTRODUCTION
In Chapter 4, I discussed how radiation interacts with matter and,
based on that, how an individual beam can be “constructed.” The
result could look something like the beam whose dose distribution
within one section of the patient is illustrated in Figure 6.1. However,
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