ABSTRACT

In the current radiation therapy practice, treatment plans are gen-erated based on a snapshot of the patient’s anatomy captured during treatment simulation and then delivered fractionally over a number of weeks. However, the patient’s anatomy may vary signicantly from fraction to fraction. ese variations occur when a patient loses weight, when

CONTENTS 21.1 Introduction 351 21.2 Overall Workow of SCORE System 353 21.3GPU Modules in SCORE System 354

21.3.1GUI of SCORE System 354 21.3.2DIR-Based Autocontouring 355 21.3.3Plan Reoptimization 356

21.3.3.1DDC Matrix Calculation 356 21.3.3.2Plan Reoptimization 358

21.3.4Dose Calculation 359 21.4Experimental Results 360 21.5Discussion and Conclusions 361 References 362

the tumor regresses during therapy [1-3], when organs such as bladder and rectum have dierent lling status [4], etc. With the advent of onboard cone-beam computed tomography (CBCT), interfraction geometry variations can be readily measured before each treatment fraction and the static radiation therapy process can potentially be transformed into a dynamic one, that is, online adaptive radiation therapy (ART) [5,6].