Open AccessStudy of a spherical phantom for Gamma knife dosimetry
Author(s) -
Zhu Dengsong,
Austerlitz Carlos,
Benhabib Sidi,
Mota Helvecio,
Allison Ron R.,
Campos Diana
Publication year - 2010
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1120/jacmp.v11i2.3130
Subject(s) - imaging phantom , dosimetry , gamma knife , medical physics , physics , nuclear medicine , radiosurgery , medicine , radiation therapy , radiology
Four 16 cm diameter spherical phantoms were modeled in this study: a homogenous water phantom, and three water phantoms with 1 cm thick shell each made of different materials (PMMA, Plastic Water™ and polystyrene). The PENELOPE Monte Carlo code was utilized to simulate photon beams from the Leksell Gamma Knife (LGK) unit and to determine absorbed dose to water ( D w ) from a single 18 mm beam delivered to each phantom. A score spherical volume of 0.007 cm 3 was used to simulate the dimensions of the sensitive volume of the Exradin A‐16 ionization chamber, in the center of the phantom. In conclusion, the PMMA shell filled with water required a small correction for the determination of the absorbed dose, while remaining within the statistical uncertainty of the calculations ( ± 0.71 ) . Plastic Water™ and polystyrene shells can be used without correction. There is a potential advantage to measuring the 4 mm helmet output using these spherical water phantoms. PACS numbers: 87.10.Rt, 87.50.cm