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Unintended attenuation in the Leksell Gamma Knife® Perfexion™ calibration‐phantom adaptor and its effect on dose calibration
Author(s) -
Bhatnagar Jagdish P.,
Novotny Josef,
Quader Mubina A.,
Bednarz Greg,
Huq M. Saiful
Publication year - 2009
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 - 10.1118/1.3093240
Subject(s) - imaging phantom , calibration , attenuation , materials science , nuclear medicine , dosimetry , optics , physics , medicine , quantum mechanics
The calibration of Leksell Gamma Knife Perfexion (LGK PFX) is performed using a spherical polystyrene phantom 160 mm in diameter, which is provided by the manufacturer. This is the same phantom that has been used with LGK models U, B, C, and 4C. The polystyrene phantom is held in irradiation position by an aluminum adaptor, which has stainless steel side‐fixation screws. The phantom adaptor partially attenuates the beams from sectors 3 and 7 by 3.2% and 4.6%, respectively. This unintended attenuation introduces a systematic error in dose calibration. The overall effect of phantom‐adaptor attenuation on output calibration of the LGK PFX unit is to underestimate output by about 1.0%.