Commissioning and Clinical Validation of Geneva Universal Brachytherapy Applicator: Acceptance Testing and TPS Integration
Abstract
Purpose
This study details the formal acceptance testing and clinical validation of the Elekta/Nucletron Geneva gynecological HDR applicators. The objective was to establish a standardized commissioning framework to verify physical integrity, dimensional accuracy, source positioning, Treatment Planning System (TPS) model, and end-to-end clinical readiness prior to first patient use.
Methods
We assessed a comprehensive evaluation of a Geneva applicator kit comprising 0, 30, and 45 degree-tandems, interstitial ovoids (15-30 mm), rectal retractors, and connection accessories. The acceptance protocol consisted of six stages. First, a visual and physical inspection was conducted to verify mechanical joints and structural integrity. Second, radiographic validation was performed to assess internal lumens and verify dimensions against manufacturer specifications. Third, source position verification was completed using a Source Position Check Ruler (SPCR) and radio-opaque markers to confirm internal path lengths and first dwell position accuracy. Fourth, autoradiographic film analysis was performed using Gafchromic film and a 3D-printed phantom to verify the location of the first dwell position. Fifth, model integrity was confirmed by overlaying manufacturer 3D models onto acquired CT datasets. Sixth, an end-to-end test was performed using a simulated treatment plan, including a needle insertion scenario, to confirm system deliverability.
Results
No physical defects or weak points were identified during visual or radiographic inspection. Nominal applicator diameters and lengths were confirmed through physical measurement and CT imaging, with all dimensions within a 1 mm tolerance. SPCR simulation matched expected virtual source positions for all evaluated applicators. Radiographic film confirmed accurate placement of the first dwell position (within 0.5mm). TPS applicator models demonstrated accurate geometric alignment when overlaid onto CT-scanned applicators. The end-to-end test plan was successfully delivered as intended.
Conclusion
The Geneva applicator kit meets safety and functional requirements for clinical implementation. The methodology developed provides a robust and adaptable framework to commission advanced brachytherapy applicators.