Program Information
TG43-TG186 Dosimetric Comparison of a SAVI Applicator
Z Richards , D Wilkinson*, Cleveland Clinic Foundation, Cleveland, OH
Presentations
SU-I-GPD-T-38 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: To compare TG-43 and TG-186 dose calculations for the Strut-Adjusted Volume Implant (SAVI) partial breast irradiation device
Methods: : SAVI cases were provided by Cianna Medical, and were modeled and planned using the Oncentra treatment planning system (v 4.. Three types of SAVI devices were used in the study: a six catheter device, an eight strut device, and a ten strut device, each having a central catheter. The air cavity was contoured and assigned the default air density. The dose distribution was calculated using TG-43 and TG-186 for the center catheter having five active dwell positions (typical of our partial breast brachytherapy practice). The dose ratios were calculated between TG-43 and TG-186 and compared to the published Monte Carlo results for each type of SAVI device.
Results: The dose calculated at the near air-tissue interface was reduced 2 to 6% when TG186 was used. For the other depths examined, the dose ratio of TG186/TG43 increased from approximately 1 to 1.04 as the cavity volume increased (six strut device to ten strut device).
Conclusion: The air-tissue interface dose decrease using TG 186 was similar to what was found with another air-filled applicator. Similar to a Monte Carlo calculation, the ten strut device showed a greater effect at depth in the tissue compared to the six strut device.
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