FAQs - Radiation Therapy

Images courtesy of Martin Keisch, MD
University of Miami

1. Can a patient undergo radiation treatment with an AeroForm® Expander in place?
A patient who requires radiation treatment and has an AeroForm Expander implanted may either expand and exchange to a standard breast implant prior to radiation or undergo radiation with the Expander in place. This should be discussed with the radiation oncologist, as the appropriate timing of radiation may vary by center and individual patient needs.
2. What information about AeroForm is available for the radiation oncologist?
The radiation oncologist should be made aware of the fact that a patient has an AeroForm Expander in place. Although not unique for radiation oncology, the treatment plan must account for the presence of the metal reservoir and the air-filled cavity. AirXpanders has developed a guideline that provides technical information about the device which is very important when planning radiation treatment. These Device Modeling Guidelines are available through customer service or your sales representative.
3. Can the AeroForm Expander be deflated, if necessary for radiation treatment?
No, once volume has been added to the AeroForm Expander, it cannot be removed except by deflating the expander with a needle, which will disable the device. In the case of bilateral expanders, if the contralateral side is fully expanded, it may be difficult to develop a treatment plan that covers the planned target volume for the breast while avoiding the unaffected breast. To avoid this situation, wait for the pathology results prior to expanding and minimize expansion on the contralateral side to just filling the pocket prior to radiation treatment. The contralateral side can be fully expanded after radiation treatment is completed.
4. Can a patient continue expanding while undergoing radiation treatment?
No, active expansion should not be done during the time the patient is undergoing radiation treatment. It is important that the volume of the expander remain constant once the treatment plan is completed and until radiation treatment is finished. The patient should be instructed to avoid expansion during radiation treatment; alternatively the controller(s) should be kept in the surgeon’s or radiation oncologist’s office.
5. Will the volume of the AeroForm Expander be constant over the course of radiation?
Yes, the AeroForm Expander has a permeation rate of approximately 0.4-0.5cc per day, thus over the course of radiation treatment the loss of volume is minimal and should not affect the treatment plan. If excess volume loss is noted, maintenance dosing may be done, as needed, to keep the volume constant.
6. Does radiation impact the function of the AeroForm Expander?
No, functional testing was conducted and concluded that the electronics inside the Expander continue to function properly after exposure to radiation levels up to 75 Gy, which is well above the maximum total dose typically used in post-mastectomy radiation therapy ~ 50Gy. (Rembert)
7. Can a patient have an MRI while the AeroForm Expander is implanted?
No, the AeroForm Expander is not MRI compatible. As with saline expanders, which also contain metal components, it is unsafe to have an MRI with an AeroForm Expander in place. In addition, the function of the AeroForm Expander may be affected by exposure to a magnetic environment.
8. What are factors to consider when planning radiation delivery with AeroForm Expanders?
  • The AeroForm Expander is filled with gas (CO2) instead of liquid which may impact treatment planning as the radiation X-ray beam travels through a gas medium differently than through liquid or tissue.
  • There is an internal stainless-steel reservoir affixed to the posterior wall of the Expander - away from the skin surface. A saline expander also has a metal component (magnetic port) which is located on the anterior wall of the expander - closer to the skin surface.
  • The AeroForm reservoir is not uniformly dense; there are 3 distinct sections. The various densities must be taken into account when developing a treatment plan.
9. What studies have been published on radiation with the AeroForm Expander?
Moni J. et al., Dosimetric Impact of the AeroForm Tissue Expander in post-mastectomy radiation therapy – An ex vivo analysis (Practical Radiation Oncology April 2015)

Tran, T. et al., A dosimetric analysis of the aeroform™ tissue expander in radiation therapy (Int J Cancer Ther Oncol 2014; 2(3):020316. DOI: 10.14319/ijcto.0203.16)

Tran, T. et al., A dosimetric analysis of the aeroform™ tissue expander in radiation therapy (Int J Cancer Ther Oncol 2014; 2(3):020316. DOI: 10.14319/ijcto.0203.16)

Purpose: The aim of this study is to evaluate the effects of the metallic reservoir and the use of gas within the AeroForm™ tissue expander with respect to the radiation dose distribution.

Conclusion: Dosimetric effects due to the metallic reservoir within the AeroForm breast tissue expander have been demonstrated and have been observed to be significant. To increase the dosimetric accuracy when contouring, individual components of the reservoir should be distinguished. Our in-vivo experiment showed that dose homogeneity was difficult due to the metallic reservoir and we recommend stringent patient dose monitoring when using this expander during radiotherapy.

Kuo JV et al. Dose Measurements in the post-mastectomy irradiation of a patient with a gas based tissue Expander (ASTRO Meeting 2013)

Rembert J. et al., Radiation Testing of the AeroForm CO2-based breast tissue Expander implant (Radiation Oncology 2013 8:235)
Images courtesy of Martin Keisch, MD
University of Miami