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Commissioning a Commercial HDR Brachytherapy Multi-Channel Vaginal Cylinder for Clinical Use Without the Use of Radiographic Film

G Nichols

G Nichols*, M Price, Univ North Carolina, Chapel Hill, NC

SU-E-T-147 Sunday 3:00PM - 6:00PM Room: Exhibit Hall

Purpose: To develop a set of procedures that utilize radiochromic film, a conventional kV simulator, and commonly-available, vendor-supplied QA devices to commission an HDR brachytherapy multi-channel vaginal cylinder (MCVC) for clinical use.

Methods: A series of images were acquired utilizing a combination of radiochromic film, planar kV imaging, and device immobilization. Using this information, relative coordinates used for source localization were registered absolutely with respect to MCVC and afterloader coordinate systems. With this knowledge, a method for MCVC channel identification and treatment planning was developed. Absolute dosimetry of resulting plans was verified utilizing radiochromic film measurements in water.

Results: Vendor-supplied index lengths of 1293 and 1500 mm were confirmed for the peripheral and central MCVC channels, respectively. For treatment planning purposes, the distance from the distal tip of each peripheral MCVC channel was verified to be consistent for each supplied cylinder diameter: 25, 30, and 35 mm. Additionally, a method that exploits physical characteristics of the applicator has been developed to facilitate precise and reproducible dwell position localization and catheter identification. Preliminary analysis of measured and planned dose delivered to planes parallel to the long-axis of the cylinder show agreement within 7% in water for a variety of cylinder diameters and loadings.

Conclusion: A method has been developed to commission a commonly available MCVC for clinical use without the use of radiographic film.

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