Dose perturbation study in a multichannel breast brachytherapy device

作者：Slessinger Eric D^*; Fletcher Rodney; Das Indra J

来源：Journal of Contemporary Brachytherapy, 2011, 3(4): 220-223.

DOI：10.5114/jcb.2011.26473

• brachytherapy
• breast cancer
• dose perturbation
• PBI

Purpose: A study was conducted to determine the dosimetric effects resulting from air pockets and high atomic number (Z) contrast medium within a multichannel breast brachytherapy device.
Material and methods: A 5-6 cm diameter Contura (SenoRx) brachytherapy device was inflated using 37 cm(3) of saline. Baseline dose falloff from an HDR Iridium-192 source was measured with the Iridium source centered in the central channel and an anterior off-center channel. Data were collected at distances from 1 to 50mm. Comparison studies were conducted with identically inflated volume containing varied air pocket volumes (1-4 cm(3)) and concentrations of contrast solution (3%, 6%, and 9% by volume). Dose perturbation factors (DPF) were computed and evaluated.
Results: Dose perturbations due to air pockets and contrast solutions were observed. As the volume of air increased, the DPF increased by approximately 2.25%/cm(3). The effect was consistent for both channels. The contrast effects were more complex. The 3% contrast media had minimal dose perturbation. The 6% contrast solution caused dose reduction of 1.0% from the central channel but 1.5% dose increase from the anterior channel. The 9% contrast solution caused dose reductions by 4.0% (from central channel) and 3.0% (from anterior channel). The DPF from all contrast solutions mode rated with increasing distance.
Conclusions: Dose perturbations due to air pockets and high-Z contrast solution can be significant. It is important to control these effects to avoid dose errors.

• 出版日期2011