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Dosimetric characterization of a bi‐directional micromultileaf collimator for stereotactic applications
Author(s) -
Bucciolini M.,
Russo S.,
Buonamici F. Banci,
Pini S.,
Silli P.
Publication year - 2002
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1487423
Subject(s) - collimator , collimated light , dosimetry , dosimeter , ionization chamber , optics , materials science , linear particle accelerator , dose profile , nuclear medicine , medical physics , beam (structure) , physics , ionization , medicine , laser , ion , quantum mechanics
A 6 MV photon beam from Linac SL75‐5 has been collimated with a new micromultileaf device that is able to shape the field in the two orthogonal directions with four banks of leaves. This is the first clinical installation of the collimator and in this paper the dosimetric characterization of the system is reported. The dosimetric parameters required by the treatment planning system used for the dose calculation in the patient are: tissue maximum ratios, output factors, transmission and leakage of the leaves, penumbra values. Ionization chambers, silicon diode, radiographic films, and LiF thermoluminescent dosimeters have been employed for measurements of absolute dose and beam dosimetric data. Measurements with different dosimeters supply results in reasonable agreement among them and consistent with data available in literature for other models of micromultileaf collimator; that permits the use of the measured parameters for clinical applications. The discrepancies between results obtained with the different detectors (around 2%) for the analyzed parameters can be considered an indication of the accuracy that can be reached by current stereotactic dosimetry.