Hoshina Masataka, Noguchi Masaya, Sekihara Hirotoshi, Masuda Koichi, Shinmura Mitsuko, Sugahara Shinji
Radiology and Radiation Oncology, Tokyo Medical University Ibaraki Medical Center, Inashiki-gun, JPN.
Nursing, Tokyo Medical University Ibaraki Medical Center, Inashiki-gun, JPN.
Cureus. 2024 Jan 29;16(1):e53183. doi: 10.7759/cureus.53183. eCollection 2024 Jan.
Background Left-sided breast cancer radiotherapy may increase the risk of cardiovascular death due to possible heart irradiation. The reproducibility of the chest wall to heart distance in deep inspiration breath-hold (DIBH) was studied using a laser sensor with visual feedback. Methodology A total of 10 consecutive postoperative left-sided breast cancer cases receiving DIBH radiotherapy between December 2022 and September 2023 were retrospectively investigated. The prescribed dose was 50 Gy in 25 fractions. An Anzai respiratory gating system, AZ-733VI (Anzai, Tokyo, Japan), was employed that has a laser displacement sensor and a visual feedback device. An Elekta linac with a cone-beam CT unit, Axesse (Elekta AB, Stockholm, Sweden), was used in this study. The interfractional changes in the chest wall to heart distance among 25 fractions were analyzed for each of the 10 patients in each coordinate axis. In addition, the median with the 95% confidence interval (CI) and interquartile range (IQR) for all 250 fractions were calculated in each axis to assess the reproducibility of our DIBH technique. Results The medians of the interfractional changes in the chest wall to heart distance in each of the 10 patients ranged from -2 mm to 3 mm, -1 mm to 3 mm, and -2 mm to 1 mm in the lateral (X), superior-inferior (Y), and anterior-posterior (Z) directions, respectively. For all 10 cases, the medians were 1 mm (95% CI = 0.72 to 1.28 mm) in X, 1 mm (95% CI = 0.76 to 1.24 mm) in Y, and 0 mm (95% CI = -0.20 to 0.20 mm) in Z directions, whereas the IQRs were 4 mm in X, 2 mm in Y and 2 mm in Z directions. The measured IQRs were two to three times smaller than those shown in a previous report without visual feedback, suggesting a clinical advantage of the visual feedback in DIBH for left-sided breast cancer radiotherapy. The DIBH solution shown in this study required approximately 10 minutes from room-in to room-out, thereby not reducing the daily number of patients. Conclusions Our DIBH approach with visual feedback achieved better distance reproducibility between the chest wall and heart by a factor of two to three in terms of IQR compared to the previously reported data without visual feedback. Patient throughput was also favorable. To our knowledge, this is the first report demonstrating the chest wall to heart distance reproducibility in DIBH with visual feedback.
背景 左侧乳腺癌放疗可能因心脏受到照射而增加心血管死亡风险。本研究使用带有视觉反馈的激光传感器，对深吸气屏气（DIBH）时胸壁到心脏的距离的可重复性进行了研究。方法 回顾性调查了2022年12月至2023年9月期间连续接受DIBH放疗的10例左侧乳腺癌术后患者。处方剂量为50 Gy，分25次给予。采用了安宰呼吸门控系统AZ - 733VI（日本东京安宰公司），该系统具有激光位移传感器和视觉反馈装置。本研究使用了配备锥形束CT单元的医科达直线加速器Axesse（瑞典斯德哥尔摩医科达公司）。分析了10例患者中每个患者在25次分割中胸壁到心脏距离在各坐标轴上的分次间变化。此外，计算了所有250次分割在各轴上的中位数及其95%置信区间（CI）和四分位数间距（IQR），以评估我们的DIBH技术的可重复性。结果 10例患者中，胸壁到心脏距离在外侧（X）、上下（Y）和前后（Z）方向的分次间变化中位数分别为-2 mm至3 mm、-1 mm至3 mm和-2 mm至1 mm。对于所有10例患者，X方向中位数为1 mm（95% CI = 0.72至1.28 mm），Y方向为1 mm（95% CI = 0.76至1.24 mm），Z方向为0 mm（95% CI = -0.20至0.20 mm），而IQR在X方向为4 mm，Y方向为2 mm，Z方向为2 mm。测量得到的IQR比之前无视觉反馈报告中显示的小两到三倍，这表明视觉反馈在左侧乳腺癌放疗的DIBH中具有临床优势。本研究中所示的DIBH方案从进入治疗室到离开治疗室大约需要10分钟，因此不会减少每日患者数量。结论 与之前无视觉反馈的报告数据相比，我们采用视觉反馈的DIBH方法在IQR方面使胸壁与心脏之间的距离可重复性提高了两到三倍。患者通量也较好。据我们所知，这是第一份展示带有视觉反馈的DIBH中胸壁到心脏距离可重复性的报告。
