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On the physical, spectral, and dosimetric characteristics of a new I 125 brachytherapy source
Author(s) -
Pirchio Rosana,
Galiano Eduardo,
Saraví Margarita,
Banchik David,
Muñoz Carlos
Publication year - 2007
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 - 10.1118/1.2739816
Subject(s) - brachytherapy , dosimetry , medical physics , medical imaging , radiation therapy , nuclear medicine , medicine , radiology
A new I125 source under the name Braquibac™ has been developed in Argentina for interstitial brachytherapy applications. The aim of this work is to study the new seed's design and to calculate its dosimetric parameters. Radiographic and destructive tests were carried out on inactive seeds to determine the physical characteristics of the source. Values of g ( r ) , Λ , F ( r , θ ) , andφ an ( r ) , were obtained in water and air by simulation using the MCNP5 Monte Carlo code according to the methodology recommended in TG‐43 and updated in TG‐43U1. The dose rate constant was determined to be 0.937 ± 0.004 cGyh − 1U − 1(overall statistical uncertainty ± 2.7 % ). S k per unity activity was calculated to be 0.671 ± 0.003 cGycm 2h − 1mCi − 1by simulation of the seed in dry air using point detectors. Spectroscopic studies for both the new and the Amersham model 6711 seed were performed using an HPGe planar detector. The emission spectra of both seeds proved to be very similar. The anisotropy of the total photon intensity in air was measured in planes containing the seed's short and long axes using the HPGe detector. The minimum photon intensity for the new seed was 31.14 ± 3.10 % of the transverse intensity.