Monte Carlo and thermoluminescence dosimetry of the new IsoSeed registered model I25.S17 {sup 125}I interstitial brachytherapy seed

Journal Article · Tue Nov 15 04:00:00 EST 2005 · Medical Physics

DOI:https://doi.org/10.1118/1.2089588· OSTI ID:20726892

Lymperopoulou, G; Papagiannis, P; Sakelliou, L; Karaiskos, P; Sandilos, P; Przykutta, A; Baltas, D ^[1]

---

1. Nuclear and Particle Physics Section, Department of Physics, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece)

Monte Carlo simulation and experimental thermoluminescence dosimetry were utilized for the dosimetric characterization of the new IsoSeed registered model I25.S17 {sup 125}I interstitial 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 of {lambda}{sub MC}=(0.929{+-}0.014) cGy h{sup -1} U{sup -1} was adopted for the new seed. This value was then averaged with the measured value of {lambda}{sub EXP}=(0.951{+-}0.044) cGy h{sup -1} U{sup -1} to yield the proposed dose rate constant for the new seed that is equal to {lambda}=(0.940{+-}0.051) cGy h{sup -1} U{sup -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 for {sup 125}I seeds 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%)

• OSTI ID: 20726892
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 11 Vol. 32; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
ANISOTROPY
BRACHYTHERAPY
CALIBRATION STANDARDS
COMPUTERIZED SIMULATION
DOSE RATES
IODINE 125
MONTE CARLO METHOD
RADIATION SOURCE IMPLANTS
RECOMMENDATIONS
THERMOLUMINESCENCE
THERMOLUMINESCENT DOSIMETRY