Comparison between the SGRT and the conventional setup method for patients undergoing VMAT for pelvic malignancies

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Accurate patient positioning is critical for effective radiotherapy, especially for pelvic malignancies.
• Conventional methods using lasers and tattoos have limitations in precision and consistency.
• Surface Guided Radiation Treatment (SGRT) utilizes visual light cameras for real-time surface monitoring.

Purpose of the Study:

• To compare the accuracy and time efficiency of SGRT versus the conventional laser/tattoo method for patient positioning.
• To evaluate SGRT's effectiveness in patients with pelvic malignancies undergoing radiotherapy.

Main Methods:

• A study involving 34 patients (24 male prostate, 10 female gynecological) undergoing radiotherapy.
• Patients were divided into two groups: Group A (tattoo/laser) and Group B (SGRT), with 17 patients each.
• Position verification using cone beam computed tomography (CBCT) before each session; analysis of positional corrections and setup time.

Main Results:

• SGRT (Group B) demonstrated significantly smaller positional corrections across all directions (vertical, lateral, longitudinal) compared to the conventional method (Group A).
• Improvements in corrections were 16.6% (vertical), 36.7% (lateral), and 33.3% (longitudinal), with a 29.2% improvement in total corrections.
• SGRT showed greater consistency (IQR 0.25 cm vs 0.38 cm) but required a significantly longer median setup time (2.0 min vs 1.6 min).

Conclusions:

• Surface Guided Radiation Treatment (SGRT) enhances positioning accuracy for Volumetric Modulated Arc Therapy (VMAT) in pelvic cancer patients.
• Despite a longer setup time, SGRT provides superior precision compared to the conventional laser and tattoo-based positioning techniques.