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A Simple Commissioning Procedure for a HDR Brachytherapy Intracavitary Applicator

Anita Corrao

A Corrao1*, I Mihaylov2, (1) 21st Century Oncology, PROVIDENCE, RI, (2) Rhode Island Hospital / Warren Alpert Medical, PROVIDENCE, RI

PO-BPC-Exhibit Hall-12 Saturday  Room: Exhibit Hall

Purpose: To outline a commissioning procedure for a HDR brachytherapy intracavitary applicator.

Method and Materials: The described procedure is applied to Nucletrons multicatheter cylinder set with an intravaginal tube and three different intrauterine tandems. The applicators were taken apart and their dimensions were compared to the manufacturer specifications. The index length was measured for all the catheters. All applicators where CT scanned with IU3 markers placed in the central and two outer catheters on opposite sides of the applicator. Applicator sizes on the CT scans were verified. Measurements between the first dummy source and the outer edge of the applicator were performed. Treatment plans for all cylinder and tube/tandem combinations were performed. The plans consisted of a single (first) dwell position in one peripheral catheter and in the tube/tandem. The plans were delivered and autoradiographs taken with a XV film. Prior to delivery, films were marked such that the cylinder and tube/tandem positions and dimensions can be visualized after film processing.

Results: The index length was measured for all the catheters - the central catheter measured 150 cm, while the outer catheters measured 129.3 cm (per vendor specifications). Cylinder integrity was visually verified in the TPS. The measured autoradiograph distances between the source positions and the cylinder/tube/tandem walls matched the measured distances between the dummy sources and the cylinder/tube/tandem walls in the TPS.

Conclusion: A simple procedure for HDR brachytherapy applicator commissioning was presented. Verification of the applicators integrity was verified. Coincidence between geometric and dosimetric properties was validated.

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