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Updated: Jun 22, 2026

Irradiator Commissioning and Dosimetry for Assessment of LQ α and β Parameters, Radiation Dosing Schema, and in vivo Dose Deposition
Published on: March 11, 2021
Unintended attenuation in the Leksell Gamma Knife Perfexion calibration-phantom adaptor and its effect on dose
Jagdish P Bhatnagar1, Josef Novotny, Mubina A Quader
1Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15217, USA.
Abstract:
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%.

