Comparison of sliding window and field-in-field techniques for tangential whole breast irradiation using the Halcyon and Synergy Agility systems

Abstract

Background To implement a tangential treatment technique for whole breast irradiation using the Varian Halcyon and to compare it with Elekta Synergy Agility plans. Methods For 20 patients two comparable treatment plans with respect to dose coverage and normal tissue sparing were generated. Tangential field-in-field treatment plans (Pinnacle/Synergy) were replanned using the sliding window technique (Eclipse/Halcyon). Plan specific QA was performed using the portal Dosimetry and the ArcCHECK phantom. Imaging and treatment dose were evaluated for treatment delivery on both systems using a modified CIRS Phantom. Results The mean number of monitor units for a fraction dose of 2.67 Gy was 515 MUs and 260 MUs for Halcyon and Synergy Agility plans, respectively. The homogeneity index and dose coverage were similar for both treatment units. The plan specific QA showed good agreement between measured and calculated plans. All Halcyon plans passed portal dosimetry QA (3%/2 mm) with 100% points passing and ArcCheck QA (3%/2 mm) with 99.5%. Measurement of the cumulated treatment and imaging dose with the CIRS phantom resulted in lower dose to the contralateral breast for the Halcyon plans. Conclusions For the Varian Halcyon a plan quality similar to the Elekta Synergy device was achieved. For the Halcyon plans the dose contribution from the treatment fields to the contralateral breast was even lower due to less interleaf transmission of the Halcyon MLC and a lower contribution of scattered dose from the collimator system.

Benchmarking halcyon ring delivery system for hypofractionated breast radiotherapy: Validation and clinical implementation of the fast‐forward trial

“…have shown that fast, safe, and effective treatment delivery is possible with Halcyon RDS for conventionally fractionated daily treatment for head and neck, whole breast, and prostate. Moreover, many other researchers have demonstrated the clinical feasibility of using Halcyon RDS for the conventional daily treatment of whole breast patients using either a dynamically flattened beam (DFB) or FFF beam with tangential fields or field‐in‐field approach including bilateral breast 7–14 . Our study is to complement those previous investigations and is the first to benchmark on the evaluation and clinical implementation of Halcyon RDS for the hypofractionated Fast‐Forward trial for APBI patients.…”

“…Moreover, many other researchers have demonstrated the clinical feasibility of using Halcyon RDS for the conventional daily treatment of whole breast patients using either a dynamically flattened beam (DFB) or FFF beam with tangential fields or field-in-field approach including bilateral breast. [7][8][9][10][11][12][13][14] Our study is to complement those previous investigations and is the first to benchmark on the evaluation and clinical implementation of Halcyon RDS for the hypofractionated Fast-Forward trial for APBI patients. In this technical report, we have evaluated plan quality, treatment delivery efficiency, and accuracy of APBI on Halcyon by benchmarking with high-quality APBI treatments that were delivered on our SBRT-dedicated TrueBeam.…”

Characterization of a novel VenusX orthogonal dual‐layer multileaf collimator

“…Current MLCs typically feature a single layer 19 ; however, multilayer MLCs have been gradually introduced to clinical settings 25,27 . Multilayer MLCs offer several important advantages, such as reducing normal organ dose outside the target volume, and requiring less time and fewer monitor units 10,19,28–30 . Although dual‐layer micro‐MLC (DmMLC) uses an orthogonal dual‐layer design, there are two main differences between the DmMLC and αMLC.…”

Characterization of a novel VenusX orthogonal dual-layer multileaf collimator

“…Current MLCs typically feature a single layer [18]; however, multilayer MLCs have been gradually introduced to clinical settings [23,24]. Multilayer MLCs have several important advantages, such as reducing normal organ dose outside the target volume, less time and monitor units [10,18,[25][26][27].…”