Research Papers:

Dosimetric impact of intermediate dose calculation for optimization convergence error

Byung Do Park, Tae Gyu Kim and Jong Eon Kim _

PDF  |  HTML  |  How to cite

Oncotarget. 2016; 7:37589-37598. https://doi.org/10.18632/oncotarget.7743

Metrics: PDF 1443 views  |   HTML 1651 views  |   ?  


Byung Do Park1, Tae Gyu Kim1, Jong Eon Kim2

1Department of Radiation Oncology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea

2Department of Radiological Science, Kaya University, Gimhae, Korea

Correspondence to:

Jong Eon Kim, e-mail: [email protected]

Keywords: intensity modulated radiation therapy (IMRT), intermediate dose calculation, anisotropic analytical algorithm (AAA)

Received: January 12, 2016     Accepted: February 11, 2016     Published: February 26, 2016


Intensity-modulated radiation therapy (IMRT) provides the protection of the normal organs and a precise treatment plan through its optimization process. However, the final dose-volume histogram (DVH) obtained by this technique differs from the optimal DVH, owing to optimization convergence errors. Herein, intermediate dose calculation was applied to IMRT plans during the optimization process to solve these issues.

Homogeneous and heterogeneous targets were delineated on a virtual phantom, and the final DVH for the target volume was assessed on the target coverage. The IMRT plans of 30 patients were established to evaluate the usefulness of intermediate dose calculation.

The target coverage results were analogous in the three plans with homogeneous targets. Conversely, conformity indices (conformity index [CI], heterogeneity index [HI], and uniformity index [UI]) of plans with intermediate dose calculation were estimated to be more homogenous than plans without this option for heterogeneous targets (CI, 0.371 vs. 1.000; HI, 0.104 vs. 0.036; UI, 1.099 vs. 1.031 for Phantom B; and CI, 0.318 vs. 0.956; HI, 0.167 vs. 0.076; UI, 1.165 vs. 1.057 for Phantom C). In brain and prostate cancers, a slight difference between plans calculated with anisotropic analytical algorithm (AAA) was observed (HI, p = 0.043, UI, p = 0.043 for brain; HI, p = 0.042, UI, p = 0.043 for prostate). All target coverage indices were improved by intermediate dose calculation in lung cancer cases (p = 0.043).

In conclusion, intermediate dose calculation in IMRT plans improves the target coverage in the target volume around heterogeneous materials. Moreover, the optimization time can be reduced.

Creative Commons License All site content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 License.
PII: 7743