Department of Radiology, Gifu University Hospital, Yanagido 1-1, Gifu, Japan.
Radiol Oncol. 2014 Jan 22;48(1):94-8. doi: 10.2478/raon-2013-0032. eCollection 2014 Mar.
This study aimed to evaluate whether the field-in-field (FIF) technique was more vulnerable to the impact of respiratory motion than irradiation using physical wedges (PWs).
Ten patients with early stage breast cancer were enrolled. Computed tomography (CT) was performed during free breathing (FB). After the FB-CT data set acquisition, 2 additional CT scans were obtained during a held breath after light inhalation (IN) and light exhalation (EX). Based on the FB-CT images, 2 different treatment plans were created for the entire breast for each patient and copied to the IN-CT and EX-CT images. The amount of change in the volume of the target receiving 107%, 95%, and 90% of the prescription dose (V107%, V95%, and V90%, respectively), on the IN-plan and EX-plan compared with the FB-plan were evaluated.
The V107%, V95%, and V90% were significantly larger for the IN-plan than for the FB-plan in both the FIF technique and PW technique. While the amount of change in the V107% was significantly smaller in the FIF than in the PW plan, the amount of change in the V95% and V90% was significantly larger in the FIF plan. Thus, the increase in the V107% was smaller while the increases in the V95% and V90% were larger in the FIF than in the PW plan.
During respiratory motion, the dose parameters stay within acceptable range irrespective of irradiation technique used although the amount of change in dose parameters was smaller with FIF technique.
本研究旨在评估场中(field-in-field，FIF)技术是否比使用物理楔形板(physical wedges，PW)更容易受到呼吸运动的影响。
共纳入 10 例早期乳腺癌患者。在自由呼吸(free breathing，FB)期间进行计算机断层扫描(computed tomography，CT)。在 FB-CT 数据集采集后，在轻吸气(IN)和轻呼气(EX)后屏气期间，获得另外 2 次 CT 扫描。基于 FB-CT 图像，为每位患者的整个乳房创建了 2 个不同的治疗计划，并复制到 IN-CT 和 EX-CT 图像。评估目标体积接收 107%、95%和 90%处方剂量(V107%、V95%和 V90%，分别)的变化量，即在 IN 计划和 EX 计划与 FB 计划相比。
在 FIF 技术和 PW 技术中，IN 计划的 V107%、V95%和 V90%均明显大于 FB 计划。虽然 FIF 计划中 V107%的变化量明显小于 PW 计划，但 V95%和 V90%的变化量明显大于 FIF 计划。因此，与 PW 计划相比，FIF 计划中 V107%的增加较小，而 V95%和 V90%的增加较大。
在呼吸运动期间，剂量参数保持在可接受范围内，无论使用何种照射技术，尽管 FIF 技术的剂量参数变化量较小。
