Daily stereotactic ultrasound prostate targeting: inter-user variability

Area of Science:

• Radiation Oncology
• Medical Imaging
• Radiotherapy Physics

Background:

• Accurate patient positioning is critical for effective prostate radiotherapy.
• Ultrasound-targeting devices offer real-time guidance for patient setup.
• Inter-user variability in setup procedures can impact treatment precision.

Purpose of the Study:

• To analyze inter-user variability in patient setup for prostate radiotherapy using a stereotactic ultrasound-targeting device.
• To assess the impact of user experience on setup accuracy and consistency.
• To evaluate the effectiveness of ultrasound-guided setup in improving treatment precision.

Main Methods:

• Twenty prostate cancer patients underwent setup analysis using an ultrasound-targeting device.
• Setup variations were assessed by radiation oncologists, medical physicists, radiation technologists (RTTs), and a radiologist with varying experience levels.
• Control CT scans were used as the gold standard to evaluate virtual targeting and residual setup errors.

Main Results:

• Virtual setup ranges varied between users, with experienced users showing reduced variability.
• Ultrasound-guided setup significantly improved prostate positioning by an average of 63.1% in experienced users and 35.1% in inexperienced users (p<0.0001).
• Over 97% of attempted setups resulted in improved accuracy, with only 2.7% introducing larger errors than the initial setup.

Conclusions:

• Ultrasound-guided treatment setup for prostate cancer is achievable with high inter-user consistency.
• The system demonstrably improves treatment setup accuracy in the vast majority of cases.
• User experience is a key factor in minimizing setup variability and maximizing accuracy improvements.