ABSTRACT
Since those early times in computer-aided treatment planning, the technology has advanced rapidly, in some cases now driving the technological development as computer algorithms become more sophisticated and accurate. Certainly, the advent of hardware for the delivery of intensity-modulated radiotherapy (IMRT) through the use of motorized and computer controlled multileaf collimators was at least partially accelerated through the prior development of optimization approaches for the calculation of arbitrarily complex photon fluence patterns. It is not an overstatement to talk of a revolution in radiotherapy with the introduction of IMRT [and its natural
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
8.2 Treatment Planning Process for Particle Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
8.3 Patient Immobilization and Imaging . . . . . . 153 8.3.1 Patient Immobilization . . . . . . . . . . . . 153 8.3.2 Imaging for Particle Therapy . . . . . . 154
8.4 Volume Definition . . . . . . . . . . . . . . . . . . . . . . 155 8.4.1 Target Volumes . . . . . . . . . . . . . . . . . . 155 8.4.2 Organs at Risk . . . . . . . . . . . . . . . . . . . 156 8.4.3 Technical Volumes . . . . . . . . . . . . . . . 157
8.5 Field Selection . . . . . . . . . . . . . . . . . . . . . . . . 157 8.5.1 Clinical Considerations . . . . . . . . . . . 157 8.5.2 Physical Considerations . . . . . . . . . . 158
8.6 Dose Calculation and Optimization . . . . . . . 160
8.6.1 Dose Calculation Algorithms . . . . . . . 160 8.6.2 Ray-Casting Algorithms. . . . . . . . . . . 160 8.6.3 Pencil Beam Algorithms . . . . . . . . . . 161 8.6.4 Secondary Particle Distributions . . . 162 8.6.5 Relative Biological Effectiveness . . . 163 8.6.6 Role of Optimization in Particle
Therapy . . . . . . . . . . . . . . . . . . . . . . . 164 8.6.7 Field Patching . . . . . . . . . . . . . . . . . . . 165 8.6.8 Dose Evaluation . . . . . . . . . . . . . . . . . 166 8.6.9 Geometrical Evaluations . . . . . . . . . . 166 8.6.10 Plan Robustness . . . . . . . . . . . . . . . . . 167
8.7 Treatment Delivery and the Importance of Patient Monitoring . . . . . . . . . . . . . . . . . . . . . 168
8.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
offspring, volumetric modulated arc therapy (VMAT)], and a revolution predominantly driven by treatment planning developments in the late 1980s and 1990s.
