A quantitative measure for radiation treatment plan quality.

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Planning

Background:

• Intensity modulated radiation therapy (IMRT) and volumetric modulated Arc therapy (VMAT) are advanced radiotherapy techniques.
• Objective assessment of treatment plan quality is crucial for optimizing patient outcomes.
• QUANTEC (Quantitative Analysis of Normal Tissue Effects in the Clinic) provides dose constraints for organs at risk (OARs).

Purpose of the Study:

• To develop and validate a quantitative scoring system for IMRT treatment plan quality.
• To utilize QUANTEC dose/volume parameters for assessing plan quality.
• To enable objective comparison of radiotherapy treatment plans.

Main Methods:

• Evaluated 132 IMRT and VMAT patient plans across various treatment sites.
• Calculated the shortest distance between QUANTEC objectives and the dose-volume histogram (DVH) line for each OAR.
• Normalized scores against an ideal plan to compare plan quality across sites and dosimetrists.

Main Results:

• Developed a quantitative score to assess IMRT and VMAT plan quality.
• Average scores varied by treatment site (e.g., abdomen 43.5%, brain 33.3%, chest 42.6%).
• Differences in scores were linked to OAR segmentation, OAR proximity to the planning target volume (PTV), and dosimetrist experience.

Conclusions:

• The developed scoring approach facilitates comparison of patient treatments, potentially improving patient care and outcomes.
• Further research is ongoing with a larger sample to investigate the impact of dosimetrist experience on plan quality.
• This quantitative score serves as a basis for future research in radiotherapy plan optimization.