A system for continual quality improvement of normal tissue delineation for radiation therapy treatment planning.

Purpose: To implement the "plan-do-check-act" (PDCA) cycle for the continual quality improvement of normal tissue contours used for radiation therapy treatment planning.

Methods And Materials: The CT scans of patients treated for tumors of the brain, head and neck, thorax, pancreas and prostate were selected for this study. For each scan, a radiation oncologist and a diagnostic radiologist, outlined the normal tissues ("gold" contours) using Radiation Therapy Oncology Group (RTOG) guidelines.