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Dosimetric characterization of Ir‐192 LDR elongated sources
Author(s) -
van der Laarse R.,
Granero D.,
PérezCalatayud J.,
Meigooni Ali. S.,
Ballester F.
Publication year - 2008
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 - 10.1118/1.2839102
Subject(s) - monte carlo method , dosimetry , brachytherapy , superposition principle , task group , dose rate , physics , formalism (music) , imaging phantom , medical imaging , computational physics , mathematics , optics , nuclear medicine , computer science , mathematical analysis , medical physics , statistics , radiation therapy , medicine , art , musical , visual arts , engineering management , engineering , artificial intelligence
Ir‐192 wires have been used in low‐dose‐rate brachytherapy for many years. Commercially available treatment planning systems approximate the dose rate distribution of the straight or curved wires applying the superposition principle using one of the following methods: (i) The wire is modeled as a set of point sources, (ii) the wire is modeled as a set of small straight segment wires, (iii) the values of the parameters and functions of the American Association of Physicists in Medicine (AAPM) Task Group 43 protocol are obtained for wire lengths between 3 and 7 cm assuming some simplifications. The dose rate distributions obtained using these methods for linear wires of different lengths and U‐shaped wires present significant deviations compared to those obtained by Monte Carlo. In the present study we propose a new method to model Ir192 wires of any length and shape, named the Two Lengths based Segmented method. This method uses the formalism stated in the AAPM Task Group 43 protocol for two straight wires only, 0.5 and 1 cm , to obtain the dose rate distribution around wires of any length (down to 0.3 cm and up to 10 cm ) improving on the results of the aforementioned ones. This method can easily be applied to dose calculations around other wires, such as Pd‐103 ones.