[Difference of orbit by rotation direction at automatic contouring SPECT using electrostatic capacitance sensor:...

Area of Science:

• Medical Imaging
• Sensor Technology
• Biomedical Engineering

Background:

• Automatic contouring systems enhance medical imaging precision.
• Electrostatic capacitance sensors offer non-contact distance measurement.
• System complexity can challenge accurate detector motion prediction.

Purpose of the Study:

• To evaluate the accuracy and repeatability of an automatic contouring system using an electrostatic capacitance sensor.
• To investigate the impact of detector rotation direction (clockwise vs. counterclockwise) on system accuracy.
• To assess the system's performance before and after a software update.

Main Methods:

• The system's accuracy was verified by comparing set distances with actual phantom-to-detector distances.
• Phantom scans were performed with 90-degree detector rotations in clockwise (CW) and counterclockwise (CCW) directions.
• Detector trajectories were recorded via video, and results were compared pre- and post-software update.

Main Results:

• The system demonstrated accuracy, with measured distances closely matching set distances (e.g., 12.00 mm at 10 mm set, 52.00 mm at 50 mm set).
• Counterclockwise rotation maintained distances closer to the set value compared to clockwise rotation, which sometimes exceeded it.
• Software updates significantly reduced the positional discrepancies observed with different rotation directions.

Conclusions:

• The electrostatic capacitance-based automatic contouring system is accurate and repeatable.
• Detector rotation direction influences positional accuracy, with CCW generally being more consistent.
• Software updates enhance system performance, highlighting the importance of selecting appropriate set distances for optimal patient imaging.