Breast Cancer

PV QA 4 - Poster Viewing Q&A 4

TU_9_3403 - Tattoo Free Set-up for Partial Breast Irradiation: A Feasibility Study

Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3

Tattoo Free Set-up for Partial Breast Irradiation: A Feasibility Study
R. B. Jimenez1, E. Batin2, D. Giantsoudi3, W. Hazeltine2, K. Bertolino2, S. MacDonald3, A. G. Taghian4, and D. Gierga2; 1Department of Radiation Oncology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA, 2Massachusetts General Hospital, Boston, MA, 3Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 4Harvard Medical School, Boston, MA

Purpose/Objective(s): All patients undergoing external beam accelerated partial breast irradiation (APBI) receive permanent skin-based tattoos to aid with daily set-up alignment and verification. With the advent of both body surface imaging and 2D matching of surgical clip position, tattoos may not be necessary to ensure set-up accuracy. We compared the accuracy of conventional tattoo-based set-ups to the identical process without tattoos.

Materials/Methods: Twenty patients receiving accelerated partial breast irradiation (APBI) at our institution from July 10, 2017 to February 13th, 2018 were identified. All patients received conventional tattoos per standard of care. Ten patients underwent patient set-up using tattoos for initial positioning followed by surface imaging and 2D matching of surgical clips. The other ten patients underwent initial positioning using surface imaging followed by 2D matching without reference to tattoos. The overall set-up time on the machine as well as any indicated orthogonal x-ray shifts after surface imaging for each daily fraction were recorded. X-ray shift data was used to calculate both systematic (mean and standard deviation [SD]) and random error.

Results: Of the ten patients for whom tattoos were not referenced, the average set-up time per treated fraction was 6.83 minutes versus 8.03 minutes among the tattoo cohort (p< 0.01). Mean 3D vector shifts for patients in the no tattoo group were 5.0 mm versus 5.7mm in the tattoo cohort (p=NS). The mean systematic errors in the no tattoo group were: 1.5 mm (1.6 mm SD) superior/inferior, 0.6 mm (1.5 mm SD) right/left, and 2.6 mm (2.3 mm SD) anterior/posterior directions. The mean systematic errors in the tattoo group were: 0.8 mm (2.2 mm SD) superior/inferior, 0.1 mm (2.6 mm SD) right/left, and 1.4 mm (4.0 mm SD) anterior/posterior directions. The random errors in the no tattoo group ranged from 0.6 to 0.7 mm versus 0.6 to 1.4 mm in the tattoo group.

Conclusion: Using a combination of surface imaging and 2D matching to surgical clips provides excellent accuracy in APBI patient alignment and set-up verification with the potential for reduced setup time. Therefore, skin-based tattoos may no longer be warranted for patients receiving external beam APBI. Forgoing tattoo placement may improve patient satisfaction and long-term treatment quality of life. Additional study among patients receiving whole breast radiation is under way.

Author Disclosure: R.B. Jimenez: None. E. Batin: None. D. Giantsoudi: None. A.G. Taghian: Research Grant; Impedimed. Honoraria; UpToDate. Consultant; VisionRT. D. Gierga: Honoraria; VisionRT, Ltd.

Rachel Jimenez, MD

Disclosure:
Employment
Massachusetts General Hospital: Employee: Employee

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