Gadolinium-153 as a brachytherapy isotope
2013 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 58, no 4, 957-964 p.Article in journal (Refereed) Published
The purpose of this work was to present the fundamental dosimetric characteristics of a hypothetical Gd-153 brachytherapy source using the AAPM TG-43U1 dose-calculation formalism. Gadolinium-153 is an intermediate-energy isotope that emits 40-100 keV photons with a half-life of 242 days. The rationale for considering Gd-153 as a brachytherapy source is for its potential of patient specific shielding and to enable reduced personnel shielding requirements relative to Ir-192, and as an isotope for interstitial rotating shield brachytherapy (I-RSBT). A hypothetical Gd-153 brachytherapy source with an active core of 0.84 mm diameter, 10 mm length and specific activity of 5.55 TBq of Gd-153 per gram of Gd was simulated with Geant4. The encapsulation material was stainless steel with a thickness of 0.08 mm. The radial dose function, anisotropy function and photon spectrum in water were calculated for the Gd-153 source. The simulated Gd-153 source had an activity of 242 GBq and a dose rate in water 1 cm off axis of 13.12 Gy h(-1), indicating that it would be suitable as a low-dose-rate or pulsed-dose-rate brachytherapy source. The beta particles emitted have low enough energies to be absorbed in the source encapsulation. Gadolinium-153 has an increasing radial dose function due to multiple scatter of low-energy photons. Scattered photon dose takes over with distance from the source and contributes to the majority of the absorbed dose. The anisotropy function of the Gd-153 source decreases at low polar angles, as a result of the long active core. The source is less anisotropic at polar angles away from the longitudinal axes. The anisotropy function increases with increasing distance. The Gd-153 source considered would be suitable as an intermediate-energy low-dose-rate or pulsed-dose-rate brachytherapy source. The source could provide a means for I-RSBT delivery and enable brachytherapy treatments with patient specific shielding and reduced personnel shielding requirements relative to Ir-192.
Place, publisher, year, edition, pages
2013. Vol. 58, no 4, 957-964 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-195999DOI: 10.1088/0031-9155/58/4/957ISI: 000314396800014OAI: oai:DiVA.org:uu-195999DiVA: diva2:609161