Multi-Institutional Study of End-to-End Dose Delivery Quality Assurance Testing for Image-Guided Brachytherapy Using...

Area of Science:

• Medical Physics
• Radiation Oncology
• Quality Assurance

Background:

• High-dose-rate image-guided brachytherapy (HDR-IGBT) is crucial for cancer treatment.
• Ensuring accurate dose delivery in HDR-IGBT is paramount for patient outcomes.
• Independent quality assurance is essential to validate HDR-IGBT procedures.

Purpose of the Study:

• To quantify dose delivery errors in HDR-IGBT across multiple institutions.
• To establish an independent, end-to-end dose delivery quality assurance (QA) test.
• This study represents the first multi-institutional end-to-end dose delivery assessment globally.

Main Methods:

• A postal audit utilized polymer gel dosimeters for dose measurement.
• Institutions performed image acquisition, treatment planning, and irradiation.
• Dose distributions were compared using absolute-dose gamma criteria (5%/3 mm).

Main Results:

• Thirty-five institutions participated, with a mean dose uncertainty of 3.6% ± 2.3%.
• Geometric uncertainty was 3.5 mm (k=2).
• Only 66% (23/35) of institutions passed the QA test, with common failures in treatment planning inputs (catheter offset, reconstruction).

Conclusions:

• The developed methodology effectively assesses HDR-IGBT dose delivery accuracy.
• The findings underscore a high risk of source positional errors in clinical HDR-IGBT.
• This QA approach is valuable for credentialing clinical studies and improving practice.