Barsky Andrew R, O'Grady Fionnbarr, Kennedy Christopher, Taunk Neil K, Dong Lei, Metz James M, Li Taoran, Freedman Gary M
Department of Radiation Oncology, Perelman School of Medicine of the University of Pennsylvania, Perelman Center for Advanced Medicine, Philadelphia, Pennsylvania.
Adv Radiat Oncol. 2019 Jun 8;4(4):571-578. doi: 10.1016/j.adro.2019.05.006. eCollection 2019 Oct-Dec.
Three-dimensional (3D) conformal radiation therapy is the standard technique used for adjuvant breast radiation. We report the clinical use of a novel 6-MV flattening-filter-free O-ring linear accelerator (6X-FFF ORL) for breast cancer that may improve upon 3D conformal radiation therapy with its higher dose rate and faster rotation and leaf speed than traditional C-arm gantries.
We retrospectively identified consecutive women with breast cancer who underwent surgery followed by radiation therapy to the breast or chest wall on Halcyon (Varian Medical Systems, Palo Alto, CA), a novel 6X-FFF ORL. We report their clinicopathologic information, radiation therapy details, acute toxicities, dose-volume histogram data, couch corrections, and treatment times.
Thirty-four women were treated for breast cancer on a 6X-FFF ORL between February 2018 and September 2018. All patients underwent lumpectomy (92%) or mastectomy (8%). Tumors were left sided in 44% and bilateral in 9%, and 9% included comprehensive nodal radiation therapy. Twelve percent of patients were treated prone and 29% with deep-inspiration breath hold. Standard target and normal-tissue constraints were met in nearly all plans. The 3D vector couch correction average was 0.77 ± 0.05 cm. The mean beam-on time was 2.0 ± 0.3 minutes, and mean treatment time from start of imaging to beam-off was 4.4 ± 0.4 minutes. Grade 2 dermatitis, fatigue, and breast pain occurred in 18%, 9%, and 3% of patients, respectively.
In this first clinical report of breast radiation therapy with a 6X-FFF ORL, treatment was versatile and fast for complex setups and techniques, with acceptable toxicity and organ-at-risk doses. Thus, a 6X-FFF ORL can increase throughput or reduce length of day compared with a conventional C-arm linear accelerator in departments with a busy breast service.
三维（3D）适形放射治疗是辅助性乳腺癌放疗的标准技术。我们报告了一种新型的6兆伏无均整器O型环直线加速器（6X-FFF ORL）在乳腺癌治疗中的临床应用，该加速器因其比传统C型臂机架具有更高的剂量率、更快的旋转速度和叶片速度，可能会改进3D适形放射治疗。
我们回顾性地确定了连续的乳腺癌女性患者，她们在新型6X-FFF ORL（瓦里安医疗系统公司，加利福尼亚州帕洛阿尔托）Halcyon上接受了手术，随后对乳房或胸壁进行放射治疗。我们报告了她们的临床病理信息、放射治疗细节、急性毒性、剂量体积直方图数据、治疗床校正情况和治疗时间。
2018年2月至2018年9月期间，34名女性患者在6X-FFF ORL上接受了乳腺癌治疗。所有患者均接受了乳房肿瘤切除术（92%）或乳房切除术（8%）。肿瘤位于左侧的占44%，双侧的占9%，9%包括全面的淋巴结放射治疗。12%的患者采用俯卧位治疗，29%的患者采用深吸气屏气治疗。几乎所有计划都满足了标准的靶区和正常组织限制。3D矢量治疗床校正平均值为0.77±0.05厘米。平均照射时间为2.0±0.3分钟，从开始成像到照射结束的平均治疗时间为4.4±0.4分钟。分别有18%、9%和3%的患者发生2级皮炎、疲劳和乳房疼痛。
在这份关于使用6X-FFF ORL进行乳腺癌放射治疗的首份临床报告中，对于复杂的设置和技术，治疗具有通用性且速度快，毒性和危及器官的剂量可接受。因此，在乳腺服务繁忙的科室中，与传统C型臂直线加速器相比，6X-FFF ORL可以提高治疗通量或缩短治疗时间。
