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Modifying the planning target volume to optimize the dose distribution in dynamic conformal arc therapy for large metastatic brain tumors

  • Technical Note
  • Published:
Japanese Journal of Radiology Aims and scope Submit manuscript

Abstract

Purpose

When treating large metastatic brain tumors with stereotactic radiotherapy (SRT), high dose conformity to target is difficult to achieve. Employing a modified planning target volume (mPTV) instead of the original PTV may be one way to improve the dose distribution in linear accelerator-based SRT using a dynamic conformal technique. In this study, we quantitatively analyzed the impact of a mPTV on dose distribution.

Materials and methods

Twenty-four tumors with a maximum diameter of >2 cm were collected. For each tumor, two plans were created: one used a mPTV and the other did not. The mPTV was produced by shrinking or enlarging the original PTV according to the dose distribution in the original plan. The dose conformity was evaluated and compared between the plans using a two-sided paired t test.

Results

The conformity index defined by the Radiation Therapy Oncology Group was 1.34 ± 0.10 and 1.41 ± 0.13, and Paddick’s conformity index was 0.75 ± 0.05 and 0.71 ± 0.06, for the plans with and without a mPTV, respectively. All of these improvements were statistically significant (P < 0.05).

Conclusion

The use of a mPTV can improve target conformity when planning SRT for large metastatic brain tumors.

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Acknowledgements

This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant number 15K18444).

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Authors and Affiliations

  1. Department of Radiation Oncology, Kobe City Medical Center General Hospital, 2-1-1 Minatojima-Minamimachi Chuo-ku, Kobe, 6500047, Japan

    Kengo Ogura, Yasuhiro Kosaka, Toshiyuki Imagumbai, Kazuhito Ueki, Ryo Narukami, Takayuki Hattori & Masaki Kokubo

Authors
  1. Kengo Ogura
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  2. Yasuhiro Kosaka
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  3. Toshiyuki Imagumbai
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  4. Kazuhito Ueki
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  5. Ryo Narukami
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  6. Takayuki Hattori
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  7. Masaki Kokubo
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Corresponding author

Correspondence to Kengo Ogura.

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The authors declare that they have no conflicts of interest.

Ethics statement

All procedures performed with human participants were in accordance with the ethical standards of the institutional and national research committees, and with the 1964 Declaration of Helsinki and its subsequent amendments or comparable ethical standards.

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Informed consent was obtained from all study participants.

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Ogura, K., Kosaka, Y., Imagumbai, T. et al. Modifying the planning target volume to optimize the dose distribution in dynamic conformal arc therapy for large metastatic brain tumors. Jpn J Radiol 35, 335–340 (2017). https://doi.org/10.1007/s11604-017-0639-6

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  • DOI: https://doi.org/10.1007/s11604-017-0639-6

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