Premium
Monte Carlo and thermoluminescence dosimetry of the new IsoSeed ® model I25.S17 I 125 interstitial brachytherapy seed
Author(s) -
Lymperopoulou G.,
Papagiannis P.,
Sakelliou L.,
Karaiskos P.,
Sandilos P.,
Przykutta A.,
Baltas D.
Publication year - 2005
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 - 10.1118/1.2089588
Subject(s) - dosimetry , monte carlo method , brachytherapy , thermoluminescence , medical physics , nuclear medicine , medicine , physics , nuclear physics , radiology , radiation therapy , irradiation , statistics , mathematics
Monte Carlo simulation and experimental thermoluminescence dosimetry were utilized for the dosimetric characterization of the new IsoSeed ® model I25.S17I125interstitial brachytherapy seed. The new seed design is similar to that of the selectSeed and 6711 seeds, with the exception of its molybdenum marker. Full dosimetric data are presented following the recommendations in the Update of the AAPM Task Group 43 report (TG‐43U1). A difference of 3.3% was found between Monte Carlo dose rate constant results calculated by air kerma strengths from simulations using a point detector and a detector resembling the solid angle subtended to the seed by the Wide Angle Free Air Chamber (WAFAC) in the primary standard calibration geometry. Following the TG‐43U1 recommendations, an average value ofΛ MC = ( 0.929 ± 0.014 ) cGyh − 1U − 1was adopted for the new seed. This value was then averaged with the measured value ofΛ EXP = ( 0.951 ± 0.044 ) cGyh − 1U − 1to yield the proposed dose rate constant for the new seed that is equal to Λ = ( 0.940 ± 0.051 ) cGyh − 1U − 1. The Monte Carlo calculated radial dose function and two‐dimensional (2‐D) anisotropy function results for the new seed were found in agreement with experimental results to within statistical uncertainty of repeated measurements. Monte Carlo simulations were also performed forI125seeds of similar geometry and dimensions for the purpose of comparison. The new seed presents dosimetric characteristics that are very similar to that of the selectSeed. In comparison to the most extensively studied Amersham 6711 seed, the new one presents similar dosimetric characteristics with a slightly reduced dose rate constant (1.5%).