Impact of CT scan parameters on deformable image registration accuracy using deformable thorax phantom

Area of Science:

• Medical Imaging
• Radiology
• Image Processing

Background:

• Deformable image registration (DIR) is crucial for image-guided radiation therapy.
• Accurate DIR depends on various computed tomography (CT) scan parameters.
• Evaluating CT parameters' impact on DIR accuracy is essential for optimizing treatment planning.

Purpose of the Study:

• To evaluate the deformable image registration (DIR) accuracy.
• To assess the impact of various CT scan parameters (tube voltage and reconstruction algorithms) on DIR accuracy using a deformable thorax phantom.

Main Methods:

• A deformable thorax phantom (Dephan) simulating chest wall and lung structures was used.
• Peak-exhale and peak-inhale CT images were acquired using varying tube voltages (80-135 kV) and reconstruction algorithms.
• Intensity-based DIR was performed using MIM Maestro, and accuracy was quantified using target registration error (TRE) of fiducial markers.

Main Results:

• The range of average TRE varied from 4.44-5.69 mm with different tube voltages (at FC13 algorithm).
• The range of average TRE varied from 4.26-4.59 mm with different reconstruction algorithms (at 120 kV).
• TRE varied up to 3.0 mm (3.96-6.96 mm) based on the combination of tube voltage and reconstruction algorithm.

Conclusions:

• CT scan parameters, particularly reconstruction algorithms, have a moderate impact on DIR accuracy for deformable thorax phantoms.
• Optimizing CT scan parameters is important for improving DIR accuracy in thoracic imaging applications.