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On Possible Application of a Novel Bioabsorbable Implant for Accelerated Partial Breast Irradiation with CyberKnife

P Kosterin1*, C Ozhasoglu2 , S Jang3 , S Nagda4 , M Huq5 , (1) UPMC university of Pitsburgh Medical Center, Philadelphia, PA, (2) Shadyside Hospital, Pittsburgh, PA, (3) UPMC university of Pitsburgh Medical Center, Pittsburgh, PA, (4) Penn Radiation Oncology Pennsylvania Hospital, Philadelphia, Pennsylvania, (5) University of Pittsburgh Cancer Institute, Pittsburgh, PA


(Sunday, 7/29/2018) 3:00 PM - 6:00 PM

Room: Exhibit Hall

Purpose: To evaluate possible application of a novel 3D bio-absorbable breast implant for radiation treatment with CyberKnife. Recently, a biodegradable implant/marker with metal clips was started to use in breast-conserving surgery. Although the marker was designed for mammography, it is considered to be very effective tool for reliable and accurate target delineation of the tumor bed for radiation treatment – for whole breast irradiation and/or for accelerated partial breast irradiation (APBI) with conventional linacs [M.J.Cross, et al. - World J Surg (2017) 41:464–471]. CyberKnife offers improvements over existing APBI techniques because of real-time tracking accuracy.

Methods: The implant was placed into a cavity in breast phantom made of bolus material and scanned. A plan was generated using synchrony tracking mode on CyberKnife TPS and delivered using synchrony phantom which mimics respiratory motion.

Results: The fiducials mark the site/cavity where the implant was positioned and all clips were clearly visible on CT images and were detectable with both imagers of target locating system. Delivery of the plan was possible, some obvious limits/disadvantages of the implant were reviled - one is the close positioning of the fiducial to each other. For tracking in Synchrony mode for CyberKnife it is expected to have distance of at least 2 cm between the fiducials. The implants have six fiducials and are produced of different sizes, for the small size implant the six fiducials sit too close each other. These limits/disadvantages can be circumvented by taking into consideration only few fiducials in planning.

Conclusion: For more robust application of the implant for APBI with CyberKnife, suggestions are given how to change/improve the design of the device.


Breast, Target Localization, Radiosurgery


TH- External beam- photons: cyberknife

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