Room: ePoster Forums
Purpose: Aeroformâ€™s new tissue expanders â€œAirXpandersâ€? are a new breast implant that is implanted at the time of mastectomy in breast cancer patients. Proper dosimetry modeling and treatment for these devices is a challenging endeavor with little background information in the literature.
Methods: Two patients were treated at our center using Aeroform AirXpanders following mastectomy. The standard dose and fractionation regime at our center is 5040 cGy in 28 daily fractions followed by a 1000 cGy electron boost in 5 daily fractions to the scar. The first plan was calculated using 1 cm of bolus using wet towels, whereas the second plan was calculated using 5mm tissue equivalent brass bolus, both using a field-in-field technique. The use of energy was restricted to 6 and 10 MV due to the potential for neutron activation in the canister. In addition, mono-isocenter 3-field techniques for the photon fields were used with emphasis on keeping the canister aligned during daily MV imaging. We also validated electron dosimetry using a Sun Nuclear electron diode that compared dose under backscatter conditions and using AirXpanders with tissue mimicking superflab of 1 cm.
Results: For photon dosimetry, the canister fully attenuated the tangential field leading to cold spots behind the canister. In addition, bolus assisted in achieving uniform dosimetry and reducing hot-spots; however, our first patient suffered from moist-desquamation prior to the end of treatment. Our second patient remains on treatment and side-effects remain to be seen using thinner bolus. Electron dosimetry was found to be equal when comparing full scatter conditions and measurements done at the surface of skin-equivalent bolus for the AirXpanders for a 10x10 cmÂ² electron field for a clinical setup.
Conclusion: Aeroformâ€™s AirXpanders are becoming more prominent in the clinical setting and proper consideration of its dosimetry is essential to ensure appropriate treatment.
Funding Support, Disclosures, and Conflict of Interest: Aeroform provided technical support as well as financial support for treatment of patients
Not Applicable / None Entered.