PURPOSE: To investigate the feasibility of utilizing @entity505 fiducials to increase localization accuracy of lumpectomy cavity for partial breast irradiation (PBI). METHODS: @entity505 fiducials were placed intraoperatively in the lumpectomy cavity following resection of @entity0 in 11 @entity1 . The @entity1 were scheduled to receive whole breast irradiation (WBI) with a boost or 3D-conformal PBI. WBI @entity1 were initially setup to skin tattoos using lasers, followed by orthogonal kV @entity2996 ( @entity2996 ) matching to bone per clinical practice. Cone beam CT (CBCT) was acquired weekly for offline review. For the boost component of WBI and PBI, @entity1 were setup with lasers, followed by @entity2996 matching to fiducials, with final alignment by CBCT matching to fiducials. Using @entity505 fiducials as a surrogate for the lumpectomy cavity and CBCT matching to fiducials as the gold standard, setup uncertainties to lasers, @entity2996 bone, @entity2996 fiducials, and CBCT breast were compared. RESULTS: Minimal imaging artifacts were introduced by fiducials on the planning CT and CBCT. The fiducials were sufficiently visible on @entity2996 for online localization. The mean magnitude and standard deviation of setup errors were 8.4mm    5.3 mm (n=84), 7.3mm    3.7mm (n=87), 2.2mm    1.6mm (n=40) and 4.8mm    2.6mm (n=87), for lasers, @entity2996 bone, @entity2996 fiducials and CBCT breast tissue, respectively. Significant migration occurred in one of 39 implanted fiducials in a @entity1 with a large @entity86 . CONCLUSION: @entity2996 @entity505 fiducial-based setup can improve localization accuracy with minimal imaging artifacts. With increased localization accuracy, setup uncertainties can be reduced from 8mm using @entity2996 bone matching to 3mm using @entity2996 fiducial matching for PBI treatment. This work demonstrates the feasibility of utilizing @entity505 fiducials to increase localization accuracy to the lumpectomy cavity for PBI. This may be particularly attractive for localization in the setting of proton therapy and other scenarios in which metal clips are contraindicated.

SU-E-J-37: Feasibility of Utilizing XXXX Fiducials to Increase Localization Accuracy of Lumpectomy Cavity for Partial Breast Irradiation.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast cancer'] @entity2996 :: ('MESH:C564543', 'Disease') :: ['on-board-imaging', 'OBI'] @entity86 :: ('MESH:D019106', 'Disease') :: ['postoperative seroma'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon', 'Carbon']
@entity505 :: (MESH:D002244,Chemical) :: ['Carbon']
