Author: Laura A. Doyle, Amy S. Harrison, Allyson P Koecher, Jackson D Reeves, Lindsay B Romak 👨🔬
Affiliation: Christiana Care 🌍
Purpose: Surface guided radiation therapy (SGRT) is increasingly utilized in radiation oncology, allowing for transition away from permanent skin marks to SGRT-based daily treatment setup. Following institutional experience utilizing SGRT for deep inspiration breath-hold (DIBH) treatments, a single institution composed of multiple radiation oncology centers implemented SGRT for patient setup instead of permanent tattoos (TT). To build confidence in clinical implementation and validate previously published experiences, daily verification imaging was performed, and a retrospective case-matched study was utilized to evaluate setup accuracy between tattoo-less SGRT (TL-SGRT) and the traditional 3-point TT technique for patient treatment setup.
Methods: Twenty patients, utilizing TL-SGRT for daily setup, treated to the left or right breast in the supine position were selected for analysis. Patients were retrospectively matched based on total dose, number of fractions, treatment site, treatment technique, imaging technique and frequency. Shifts were recorded for each pre-treatment imaging session from the patient electronic medical record in all three translational directions (longitudinal, lateral, vertical). Maximum and average shift data were analyzed for patients in both cohorts (TL-SGRT & TT) for all imaging sessions.
Results: For the TL-SGRT cohort, average shift data was 0.38cm, 0.23cm and 0.27cm for longitudinal, lateral, and vertical directions, respectively. The TT cohort yielded average shift data of 0.38cm, 0.28cm, 0.31cm for longitudinal, lateral, and vertical directions, respectively. A 2-tailed, paired T-test was run to determine if setup using TL-SGRT was statistically different than setup with tattoos. Comparison of average patient translations in each direction (longitudinal, lateral, vertical) were not statistically significant (P=0.936, 0.341, 0.476).
Conclusion: Implementation of TL-SGRT for patient setup without TT was not statistically different than prior clinical standard of patient setup with traditional 3-point localization technique. This builds confidence in a transition to a new clinical practice without permanent tattoos and suggests no sacrifice in treatment quality.