Comparison of the extent of hippocampal sparing according to the tilt of a patient's head during WBRT using linear accelerator-based IMRT and VMAT

Sun Young Moon, Myonggeun Yoon, Mijoo Chung, Weon Kuu Chung, Dong Wook Kim

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


In this paper, we report the results of our investigation into whole brain radiotherapy (WBRT) using linear accelerator-based intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in lung cancer patients with a high risk of metastasis to the brain. Specifically, we assessed the absorbed dose and the rate of adverse effects for several organs at risk (OAR), including the hippocampus, according to the tilt of a patient's head. We arbitrarily selected five cases where measurements were made with the patients' heads tilted forward and five cases without such tilt. We set the entire brain as the planning target volume (PTV), and the hippocampi, the lenses, the eyes, and the cochleae as the main OAR, and formulated new plans for IMRT (coplanar, non-coplanar) and VMAT (coplanar, non-coplanar). Using the dose-volume histogram (DVH), we calculated and compared the effective uniform dose (EUD), normal tissue complication probability (NTCP) of the OAR and the mean and the maximum doses of hippocampus. As a result, if the patient tilted the head forward when receiving the Linac-based treatment, for the same treatment effect in the PTV, we confirmed that a lower dose entered the OAR, such as the hippocampus, eye, lens, and cochlea. Moreover, the damage to the hippocampus was expected to be the least when receiving coplanar VMAT with the head tilted forward. Accordingly, if patients tilt their heads forward when undergoing Linac-based WBRT, we anticipate that a smaller dose would be transmitted to the OAR, resulting in better quality of life following treatment.

Original languageEnglish
Pages (from-to)657-663
Number of pages7
JournalPhysica Medica
Issue number5
Publication statusPublished - 2016 May 1

Bibliographical note

Funding Information:
This work was supported by the General Researcher Program ( NRF-2015R1D1A1A09056828 ), the National Nuclear R&D Program ( NRF-2015M2A2A7A02044502 ) of the National Research Foundation of Korea , the Nuclear Safety Research Program (Grant No. 1403019 ) of the Korea Radiation Safety Foundation, the Nuclear Safety and Security Commission, and the Radiation Technology Development Program ( 2013M2A2A4027117 ) of the Republic of Korea.

Publisher Copyright:
© 2016 Associazione Italiana di Fisica Medica.


  • Head tilting
  • Hippocampus
  • Intensity-modulated radiation therapy
  • Radiation therapy
  • Volumetric-modulated arc therapy
  • Whole brain radiotherapy

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging
  • General Physics and Astronomy


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