Department of Radiation Oncology, University of Alabama at Birmingham Alabama, Birmingham, AL, USA.
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA.
J Appl Clin Med Phys. 2021 Mar;22(3):8-15. doi: 10.1002/acm2.13127. Epub 2021 Mar 3.
A novel, breast-specific stereotactic radiotherapy device has been developed for delivery of highly conformal, accelerated partial breast irradiation. This device employs a unique, vacuum-assisted, breast cup immobilization system that applies a gentle, negative pressure to the target breast with the patient in the prone position. A device-specific patient loader is utilized for simulation scanning and device docking. Prior to clinical activation, a prospective protocol enrolled 25 patients who had been or were to be treated with breast conservation surgery and adjuvant radiotherapy for localized breast cancer. The patients underwent breast cup placement and two separate CT simulation scans. Surgical clips within the breast were mapped and positions measured against the device's integrated stereotactic fiducial/coordinate system to confirm reproducible and durable immobilization during the simulation, treatment planning, and delivery process for the device. Of the enrolled 25 patients, 16 were deemed eligible for analysis. Seventy-three clips (median, 4; mean, 4.6; range, 1-8 per patient) were mapped in these selected patients on both the first and second CT scans. X, Y, and Z coordinates were determined for the center point of each clip. Length of vector change in position was determined for each clip between the two scans. The mean displacement of implanted clips was 1.90 mm (median, 1.47 mm; range, 0.44-6.52 mm) (95% CI, 1.6-2.20 mm). Additional analyses stratified clips by position within the breast and depth into the immobilization cup. Overall, this effort validated the clinically utilized 3-mm planning target volume margin for accurate, reliable, and precise employment of the device.
一种新型的、针对乳房的立体定向放射治疗设备已经开发出来，用于提供高度适形、加速的部分乳房照射。该设备采用了独特的、真空辅助的乳房杯固定系统，该系统在患者处于俯卧位时对目标乳房施加轻柔的负压。使用特定设备的患者加载器进行模拟扫描和设备对接。在临床激活之前，一项前瞻性方案招募了 25 名接受过保乳手术和局部乳腺癌辅助放疗的患者。这些患者接受了乳房杯放置和两次单独的 CT 模拟扫描。对乳房内的手术夹进行了映射，并根据设备的集成立体定向基准/坐标系测量其位置，以确认在模拟、治疗计划和设备交付过程中具有可重复性和耐用性的固定。在登记的 25 名患者中，有 16 名符合分析条件。在这些选定的患者中，在两次 CT 扫描上共映射了 73 个夹（中位数为 4；平均值为 4.6；范围为每个患者 1-8 个）。确定了每个夹的中心点的 X、Y 和 Z 坐标。在两次扫描之间确定了每个夹位置变化的向量长度。植入夹的平均位移为 1.90 毫米（中位数为 1.47 毫米；范围为 0.44-6.52 毫米）（95%置信区间为 1.6-2.20 毫米）。进一步的分析将夹按乳房内的位置和深入固定杯的深度进行分层。总体而言，这项工作验证了临床上使用的 3 毫米计划靶区边缘，以确保设备的准确、可靠和精确使用。
