Characterization and evaluation of 2.5 MV electronic portal imaging for accurate localization of intra-and extracranial stereotactic radiosurgery

Kwang Hyun Song, Karen Chin Snyder, Jinkoo Kim, Haisen Li, Wen Ning, Robert Rusnac, Paul Jackson, James Gordon, Salim M. Siddiqui, Indrin J. Chetty

Research output: Contribution to journalArticle

5 Scopus citations


2.5 MV electronic portal imaging, available on Varian TrueBeam machines, was characterized using various phantoms in this study. Its low-contrast detectability, spatial resolution, and contrast-to-noise ratio (CNR) were compared with those of conventional 6 MV and kV planar imaging. Scatter effect in large patient body was simulated by adding solid water slabs along the beam path. The 2.5 MV imaging mode was also evaluated using clinically acquired images from 24 patients for the sites of brain, head and neck, lung, and abdomen. With respect to 6 MV, the 2.5 MV achieved higher contrast and preserved sharpness on bony structures with only half of the imaging dose. The quality of 2.5 MV imaging was comparable to that of kV imaging when the lateral separation of patient was greater than 38 cm, while the kV image quality degraded rapidly as patient separation increased. Based on the results of patient images, 2.5 MV imaging was better for cranial and extracranial SRS than the 6 MV imaging.

Original languageEnglish (US)
Pages (from-to)268-284
Number of pages17
JournalJournal of Applied Clinical Medical Physics
Issue number4
Publication statusPublished - 2016



  • 2.5 MV portal imaging
  • Stereotactic body radiation therapy
  • Stereotactic radiosurgery

ASJC Scopus subject areas

  • Radiation
  • Instrumentation
  • Radiology Nuclear Medicine and imaging

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