A quality control method for intensity-modulated radiation therapy planning based on generalized equivalent uniform...

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Planning

Background:

• Intensity-modulated radiation therapy (IMRT) requires stringent quality control for optimal patient outcomes.
• Predicting absorbed radiation doses in organs at risk (OAR) is crucial for safe and effective IMRT.
• Subjective factors can influence the optimization of IMRT plans.

Purpose of the Study:

• To develop and validate a quality control method for IMRT planning using generalized equivalent uniform dose (gEUD).
• To establish predictive fitting formulas for OAR doses based on dosimetric and volumetric parameters.
• To assess the effectiveness of the gEUD-based method in reducing subjectivity in IMRT plan optimization.

Main Methods:

• Retrospective analysis of IMRT plans for cervical carcinoma, nasopharyngeal carcinoma (NPC), and non-small cell lung cancer (NSCLC).
• Development of multiple linear regression models using normalized sub-organ at risk (sOAR) volume and normalized gEUD (a=1) for cervical and NPC.
• Development of models using planning target volume (PTV) intersection with lung, PTV diameter, and normalized gEUD (a=1) for NSCLC lung OAR.

Main Results:

• Fitting formulas demonstrated a good fit with high r-squared and significant P values.
• The gEUD-based method accurately predicted OAR doses in the verification group.
• Comparison showed reduced variability in OAR gEUD (a=1) values using the gEUD-based method versus subjective methods.

Conclusions:

• The gEUD-based method provides an effective quality control tool for IMRT planning.
• This approach minimizes the impact of subjective assessments in optimizing IMRT plans.
• The proposed method enhances the reliability and consistency of IMRT quality assurance.