title: The impact of uncertainties associated with MammoSite brachytherapy on the dose distribution in the breast.
abstract: The MammoSite radiation therapy system is a novel technique for treatment of patients with early-stage breast cancer. It was developed to overcome the longer schedules associated with external-beam radiation therapy. It consists of a small balloon (4 cm in diameter) connected to an inflation channel and a catheter for the passage of a high dose rate 192Ir brachytherapy source. The device is placed into the tumor resection cavity and inflated with a mixture of saline and radiographic contrast agent to a size that fills the cavity. A high dose rate 192Ir source is driven into the balloon center using a remote afterloader to deliver the prescribed dose at a point 1 cm away from the balloon surface. There are several uncertainties that affect the dose distribution in the MammoSite brachytherapy. They include source position deviation, balloon deformation, and the concentration of the contrast medium inside the balloon. The purpose of this study is to investigate the extent of the dose perturbation for various concentrations of the contrast medium in a MammoSite balloon using Monte Carlo simulations and thermoluminescent dosimetry. This study also combines the impact of these uncertainties on the MammoSite treatment efficacy. The current study demonstrates that the combined uncertainties associated with the MammoSite brachytherapy technique--up to the value of 2 mm balloon deformation, 1 mm source deviation, and 15% contrast concentration--have no impact on the tumor control probability.
authors.affiliation: School of Chemistry & Physics, University of Adelaide, South Australia 5005, Australia.
authors.forename: Saleh
authors.initials: S
authors.lastname: Bensaleh
authors.forename: Eva
authors.initials: E
authors.lastname: Bezak
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D009010:Monte Carlo Method; D011879:Radiotherapy Dosage
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