Researcher(s)
- Madeline Rowland, Psychology, Williams College
Faculty Mentor(s)
- Lindsay B. Romak, Radiation Oncology, Director of Adaptive Radiotherapy Program, ChristianaCare
- Laura A. Doyle, Radiation Oncology, Chief Clinical Physicist & Associate, ChristianaCare
Abstract
Purpose: About 1 in 8 women in the U.S. will be diagnosed with breast cancer. Survival rates are highest when the disease is caught early, and radiation therapy following surgery plays a vital role in preventing recurrence. For radiation to be effective, accurate patient positioning is critical to limit exposure to healthy tissue. Traditionally, this alignment uses small permanent tattoos; while effective, they can be uncomfortable and an unwanted reminder of cancer. Surface Guided Radiation Therapy (SGRT) offers a tattoo-free alternative, utilizing advanced 3D cameras (VisionRT/AlignRT) to align patients based on body surface. This study compared the setup accuracy of SGRT to traditional tattoos in breast cancer patients, while also evaluating the impact of body mass index (BMI) and age on positioning.
Methods: Data was collected from 24 patients receiving left-side breast radiation: 12 used tattoos, 12 used SGRT. For each patient, initial setup shifts (how much the table must be adjusted to match the initial patient simulation position) following imaging were recorded in three directions: superior/inferior (in/out), lateral (side-to-side), and anterior/posterior (up/down), as well as the 3D shift magnitude.
Results: Patients with tattoos had slightly larger shifts in the in/out direction, whereas SGRT showed slightly larger shifts in the up/down direction. The average total 3D shift was nearly identical (tattoo: 0.60 cm; SGRT: 0.68 cm). Only the up/down direction shift showed a statistically significant difference (p ยป 0.045), but both remained within acceptable clinical tolerance. When evaluating the influence of BMI on setup accuracy, trends showed tattoos were more affected by increased BMI, especially in side-to-side positioning. SGRT accuracy remained more stable across varying body types.
Conclusion: SGRT offers setup accuracy comparable to tattoos, providing patients with a safe, effective, and tattoo-free treatment experience. Though SGRT requires more advanced (and expensive) equipment, it avoids permanent skin markings, improves patient comfort, and allows continuous monitoring during treatment.