SU-E-J-46: Use of Brainlab-ExacTrac IGRT with Dot-Decimal Electron Compensator(BolusECT) for Accurate Patient...

Area of Science:

• Medical Physics
• Radiation Oncology
• Image-Guided Radiation Therapy (IGRT)

Background:

• Dot-Decimal electron compensators (BolusECT) are crucial for conformal dose distributions and sparing normal tissues in single electron beam treatments.
• Patient setup verification for BolusECT can be challenging due to limited space, necessitating efficient alignment methods.

Purpose of the Study:

• To validate the Brainlab-ExacTrac Image-Guided Radiation Therapy (IGRT) system for precise patient positioning with Dot-Decimal electron compensators (BolusECT).

Main Methods:

• A phantom study involved drilling tungsten BBs into a BolusECT at various depths, filling them with wax, and scanning for plan generation.
• The ExacTrac system was used to align the phantom and subsequently tested on two patients for accurate setup verification.

Main Results:

• The ExacTrac system accurately identified tungsten BBs, aligning the phantom within ±1 mm and SSD within ±0.5 mm.
• Patient setups demonstrated lateral, longitudinal, and vertical shifts within ±1 mm, with SSD within ±0.3 mm of planned values.

Conclusions:

• The Brainlab-ExacTrac IGRT system offers an efficient and fast method for aligning BolusECT, minimizing patient discomfort through reduced setup times.
• The use of tungsten BBs presents a cost-effective alternative to gold seeds for verification.
• Phantom verification is recommended prior to clinical implementation, and SSD verification post-setup is essential.