SU-E-T-204: A Prototype of Dose-Guided Radiation Therapy.

PURPOSE

With the advancement in dosimetric devices and the development of dose reconstruction algorithm, the implementation of dose-guided radiation therapy (DGRT) is feasible. In order for DGRT to be performed clinically, a prototype of DGRT was developed in this study.

METHODS

The prototype adopted a strategy for DGRT that adjusted the treatment plan for future fractions to compensate for dosimetric errors from past fractions, which included four main functional modules: management of patient plan information, dose reconstruction, dose evaluation, plan adjustment. we developed our dose reconstruction procedure, including the dosimetric calibration of the portal image acquired using electronic portal image device (EPID) during treatment and three-dimensional (3D) patient dose reconstruction based on Monte Carlo Finite-size pencil beam (MCFSPB) model and Conjugate-gradient (CG) algorithm developed by FDS Team (www.fds.org.cn). The dose evaluation tools including 3D Gamma analysis and dose-volume-histogram (DVH) analysis were also available which were used to compare the reconstruction dose with the planning dose. Finally we re-optimizing the treatment plan according to the information provided by dose evaluation.

RESULTS

In order to validate the availability of the workstation prototype, lots of experiments were carried out based on head phantom. The result showed that disagreement between the reconstructed dose and the planning dose (calculated by the Accurate Radiotherapy System (ARTS) developed by FDS Team) was observed by the DGRT prototype when there existed position error for head phantom or the accelerator delivery was not accurate.

CONCLUSIONS

An effective prototype for DGRT has been developed. With these techniques, the clinical implementation of DGRT is possible in the near future. Supported by the National Natural Science Foundation under grant No.30900386 and the National Science Foundation of Anhui Province (Nos.090413095 and 111040606Q55).