Dosimetric characteristics of a double-focused miniature multileaf collimator

Sanford L. Meeks, Francis J. Bova, Siyong Kim, Wolfgang A. Tomé, John M. Buatti, William A. Friedman

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

The dosimetric characteristics of a double-focused miniature multileaf collimator (mMLC) attached to a Philips SL75/5 linear accelerator (linac) have been investigated. Output factors, percentage depth-dose, penumbra, leaf transmission, and leakage between the leaves were measured for the 6 MV x- ray beam on this accelerator. Because leakage both through and between the leaves is minimal, the linac jaws can be kept fixed while the mMLC leaf configuration is modified for different aperture shapes. This allows for accurate output prediction using the equivalent square formalism. Percent depth-dose measured for fields defined by the mMLC show little deviation from the percent depth-dose measured for fields defined by the machine jaws or Lipowitz metal blocks. Because the mMLC matches beam divergence in both directions, allows minimal beam transmission, and has a large source-to- collimator distance, the penumbra is sharper for fields defined by the mMLC than for fields defined by the linac jaws or Lipowitz metal blocks. Based on these data, dose calculations for mMLC-defined fields can be applied with no change in procedures from those used for fields defined using conventional methods.

Original languageEnglish (US)
Pages (from-to)729-733
Number of pages5
JournalMedical Physics
Volume26
Issue number5
DOIs
Publication statusPublished - May 1999
Externally publishedYes

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Keywords

  • Multileaf collimator
  • X-ray dosimetry

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

Cite this

Meeks, S. L., Bova, F. J., Kim, S., Tomé, W. A., Buatti, J. M., & Friedman, W. A. (1999). Dosimetric characteristics of a double-focused miniature multileaf collimator. Medical Physics, 26(5), 729-733. https://doi.org/10.1118/1.598579