Case Report

Dosimetric Comparison of Halcyon vs. TrueBeam Equipment and VMAT vs. Hybrid-IMRT Techniques in Radiotherapy for Bilateral Breast Cancer Treatment

Authors: QIU XiBin, Mak KengLok, Mak KinLong, Yeung HoWai, Ho NokHang, Lo HoTing, Kwok KaSan, CHAU MingChun.

DOI: 10.33425/2835-3587.1036

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Abstract

Objective: The present investigation intends to identify the optimal radiotherapy treatment for synchronous bilateral breast cancer (SBBC) using two RT equipment with two planning techniques.

Methods: A retrospective analysis was conducted on ten consecutive SBBC patients treated at Oncology center of Kiang Wu Hospital. Dosimetric parameters of target volumes and normal tissues were compared across different equipment (Halcyon, TrueBeam) and techniques (VMAT, Hybrid-IMRT). Compliance with RTOG1005 dosimetric constraints was evaluated and statistical differences between techniques were analyzed.

Results: VMAT-Halcyon (VMAT-Hal) demonstrated significantly better target Conformity Index (CI) than HybridIMRT (P=0.02), with no significant difference in Homogeneity Index (HI). Compared to Hybrid-IMRT, VMAT-Hal reduced lung doses, particularly in high-dose regions. VMAT-Hal lowered cardiac V5 (15% vs. 22%, P=0.03) and left anterior descending artery (LAD) dose (10 Gy vs. 14 Gy). Beam-on time with Halcyon was 29% shorter than TrueBeam (2.42 min vs. 3.41 min).

Conclusion: VMAT-Halcyon is the preferred treatment modality that balancing target coverage, normal tissue sparing and treatment efficiency.

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