S Martinez*, A Harpley, A Dare, I Hajizadeh, G Seymore, G Twork, K Homann, M Price, M Morales Paliza, Vanderbilt University, Nashville, TN

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  S Martinez

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SA-B-Therapy Room-10 (Saturday, 4/17/2021) 12:30 PM - 2:30 PM [Eastern Time (GMT-4)]

Purpose: To evaluate the potential of the high-resolution diode array, SRS MapCHECK (SRSMC), to streamline the commissioning process of HDR brachytherapy surface applicators.

Methods: Dosimetric measurements were made for a set of nine brachytherapy surface cones, both with the SRSMC as well as Gafchromic EBT3 radiochromic film at several depths in a solid water phantom. Both phantoms were scanned, and doses were obtained using both the TG-43 formalism and the Acuros BV algorithm with both dose to medium (Dm) and dose to water (Dw) calculated. Comparisons between film and SRSMC measurements were conducted with dose point and profile evaluations at the water equivalent measurement plane of the SRSMC (27 mm). Dosimetric point and profile evaluations and normalized gamma analyses were performed at each relevant depth to compare the measurements and treatment planning system calculations.

Results: Examination of profile measurement data between SRSMC and film indicates a strong correspondence at the depth of interest, and the analysis time of the SRSMC is substantially less than film. Normalized gamma analysis comparisons to treatment planning algorithms were above 95% with an evaluation criteria of 2%/2mm for film measurements at 10 mm depth and above 90% for SRSMC at 27 mm water equivalent with a 3%/3mm criteria. Measurements with both systems elucidated a small off-axis irregularity in the dose distribution that results in deviations from the calculated dose profiles.

Conclusion: This work indicates the potential to streamline the HDR brachytherapy surface cone commissioning process using the SRSMC. Furthermore, the work conducted provided a thorough investigation of the cone system that will be used to inform quality assurance and clinical implementation. Moving forward, with this work serving as a foundation, clinical experience with surface applicators will pave the transition from TG-43 calculations to Acuros BV.

Keywords

Not Applicable / None Entered.

Taxonomy

TH- Brachytherapy: HDR Brachytherapy

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