A multileaf collimator field prescription preparation system for conventional radiotherapy

M. N. Du, C. X. Yu, M. Symons, D. Yan, R. Taylor, R. C. Matter, G. Gustafson, A. Martinez, J. W. Wong

Research output: Contribution to journalArticlepeer-review


Purpose: The purpose of this work is to develop a prescription preparation system for efficient field shaping using a multileaf collimator that can be used in community settings as well as research institutions. The efficiency advantage of the computer-controlled multileaf collimator, over cerrobend blocks, to shape radiation fields has been shown in conformal treatments, which typically require complete volumetric computerized tomographic data for three-dimensional radiation treatment planning-a utility not readily available to the general community. As a result, most patients today are treated with conventional radiation therapy. Therefore, we believe that it is very important to fully use the same efficiency advantage of multileaf collimator as a block replacement in conventional practice. Methods and Material: The multileaf collimator prescription preparation systems developed by us acquires prescription images from different sources, including film scanner, and radiation treatment planning systems. The multileaf collimator angle and leaf positions are set from the desired field contour defined on the prescription image, by minimizing the area discrepancies. Interactive graphical tools include manual adjustment of collimator angle and leaf positions, and definition of portions of the field edges that require maximal conformation. Data files of the final leaf positions are transferred to the multileaf collimator controller via a dedicated communication link. Results: We have implemented the field prescription preparation system and a network model for integrating the multileaf collimator and other radiotherapy modalities for routine treatments. For routine plan evaluation, isodose contours measured with film in solid water phantom at prescription depth are overlaid on the prescription image. Preliminary study indicates that the efficiency advantage of the MLC over cerrobend blocks in conformal therapy also holds true for conventional treatments. Conclusion: Our model of computer-controlled prescription, evaluation and treatment using multileaf collimators can be effectively implemented in both community settings and research institutions. The resultant increase in treatment efficiency and accuracy is now available for conventional radiotherapy.

Original languageEnglish (US)
Pages (from-to)707-714
Number of pages8
JournalInternational journal of radiation oncology, biology, physics
Issue number3
StatePublished - Oct 15 1994
Externally publishedYes


  • MLC
  • Multileaf collimator
  • Radiation field shaping

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


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