SU-E-T-404: A Prototype Program for Analyzing 4D Image Guidance Shifts for Lung SBRT

Area of Science:

• Medical Physics
• Radiation Oncology
• Image Processing

Background:

• Accurate image guidance is crucial for Stereotactic Body Radiation Therapy (SBRT).
• Four-dimensional computed tomography (4DCT) is used to account for respiratory motion in lung SBRT.
• Deriving precise image guidance shifts from 4DCT data can be challenging.

Purpose of the Study:

• To develop and evaluate a prototype in-house program for deriving image guidance shifts.
• To assist in clinical application of 4DCT for lung SBRT.
• To improve the accuracy of target re-centering in lung SBRT.

Main Methods:

• A MATLAB-based prototype program was developed.
• The program imports 4D DICOM CT datasets and accepts user-defined relative image-guided radiation therapy (IGRT) shifts.
• It redefines the dataset origin based on input shifts and exports the modified DICOM files.

Main Results:

• The shifted 4D datasets generally demonstrated acceptable re-centering of the target within the internal target volume (ITV).
• Minor adjustments (average 1mm, maximum 2mm) were noted as potentially beneficial with visualization.
• The software facilitated processing of 4DCT datasets for four lung SBRT patients.

Conclusions:

• A prototype program for shifting 4DCT image sets for lung SBRT was successfully developed and presented.
• The program demonstrated feasibility in four clinical cases.
• The workflow warrants consideration for integration into clinical practice and future software development by vendors.