Remote EPID-based dosimetric auditing using DVH patient dose analysis

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Quality Assurance

Background:

• Accurate dosimetry is critical in radiotherapy for effective cancer treatment.
• Remote auditing methods are needed to ensure consistent quality across treatment centers.
• Current methods may not fully capture patient-specific dose distributions.

Purpose of the Study:

• To develop and validate a novel remote dosimetric auditing method.
• To enable comparison of dose-volume histogram (DVH) parameters between measured and planned doses.
• To assess the method's sensitivity to common radiotherapy errors.

Main Methods:

• Adapted and combined remote electronic portal imaging (EPID) auditing with 3D dose estimation from planar measurements.
• Tested the method using error-induced plans (monitor unit, MLC positioning errors).
• Conducted a pilot audit with 11 centers using IMRT plans from clinical trials (RAVES, HPV).

Main Results:

• The method reproduced induced dose errors within 0.5%.
• It demonstrated sensitivity to multileaf collimator (MLC) positioning errors as small as 0.5 mm.
• Pilot audit DVH comparisons showed results within 3% for most plans, with a maximum difference of 3.2%.

Conclusions:

• The developed remote auditing method is effective and sensitive for dosimetric verification.
• It provides clinically meaningful DVH metrics for assessing radiotherapy quality.
• This approach can improve the understanding and consistency of radiotherapy quality across centers.