Background: Electromagnetic transponders bronchoscopically implanted near the tumor can be used to monitor deep inspiration breath hold (DIBH) for thoracic radiation therapy (RT). The feasibility and safety of this approach require further study. Methods: We enrolled patients with primary lung cancer or lung metastases. Three transponders were implanted near the tumor, followed by simulation with DIBH, free breathing, and 4D-CT as backup. The initial gating window for treatment was ±5 mm; in a second cohort, the window was incrementally reduced to determine the smallest feasible gating window. The primary endpoint was feasibility, defined as completion of RT using transponder-guided DIBH. Patients were followed for assessment of transponder- and RT-related toxicity. Results: We enrolled 48 patients (35 with primary lung cancer and 13 with lung metastases). The median distance of transponders to tumor was 1.6 cm (IQR 0.6–2.8 cm). RT delivery ranged from 3 to 35 fractions. Transponder-guided DIBH was feasible in all but two patients (96% feasible), where it failed because the distance between the transponders and the antenna was >19 cm. Among the remaining 46 patients, 6 were treated prone to keep the transponders within 19 cm of the antenna, and 40 were treated supine. The smallest feasible gating window was identified as ±3 mm. Thirty-nine (85%) patients completed one year of follow-up. Toxicities at least possibly related to transponders or the implantation procedure were grade 2 in six patients (six incidences, cough and hemoptysis), grade 3 in three patients (five incidences, cough, dyspnea, pneumonia, and supraventricular tachycardia), and grade 4 pneumonia in one patient (occurring a few days after implantation but recovered fully and completed RT). Toxicities at least possibly related to RT were grade 2 in 18 patients (41 incidences, most commonly cough, fatigue, and pneumonitis) and grade 3 in four patients (seven incidences, most commonly pneumonia), and no patients had grade 4 or higher toxicity. Conclusions: Bronchoscopically implanted electromagnetic transponder–guided DIBH lung RT is feasible and safe, allowing for precise tumor targeting and reduced normal tissue exposure. Transponder–antenna distance was the most common challenge due to a limited antenna range, which could sometimes be circumvented by prone positioning.
背景：通过支气管镜在肿瘤附近植入电磁应答器，可用于监测胸廓放疗（RT）中的深吸气屏气（DIBH）。该方法的可行性与安全性有待进一步研究。方法：我们招募了原发性肺癌或肺转移癌患者。在肿瘤附近植入三个应答器，随后进行DIBH模拟、自由呼吸模拟，并以四维CT作为备用方案。初始治疗的门控窗口为±5毫米；在第二批患者中，逐步缩小门控窗口以确定可行的最小门控窗口。主要终点是可行性，定义为使用应答器引导的DIBH完成放疗。对患者进行随访以评估应答器及放疗相关毒性。结果：共招募48例患者（35例原发性肺癌，13例肺转移癌）。应答器与肿瘤的中位距离为1.6厘米（四分位距0.6-2.8厘米）。放疗分次次数为3至35次。除两例患者外（可行性96%），应答器引导的DIBH均可行；失败原因为应答器与天线距离超过19厘米。其余46例患者中，6例采用俯卧位治疗以使应答器保持在天线19厘米范围内，40例采用仰卧位治疗。确定的最小可行门控窗口为±3毫米。39例（85%）患者完成一年随访。与应答器或植入操作至少可能相关的毒性反应：6例患者出现2级毒性（6起事件，咳嗽和咯血），3例患者出现3级毒性（5起事件，咳嗽、呼吸困难、肺炎和室上性心动过速），1例患者出现4级肺炎（植入后数日发生但完全康复并完成放疗）。与放疗至少可能相关的毒性反应：18例患者出现2级毒性（41起事件，最常见为咳嗽、疲劳和肺炎），4例患者出现3级毒性（7起事件，最常见为肺炎），无患者出现4级或更高级别毒性。结论：支气管镜植入电磁应答器引导的DIBH肺部放疗可行且安全，能够实现精准肿瘤靶向并减少正常组织照射。因天线范围有限，应答器与天线距离是最常见的挑战，但有时可通过俯卧位解决。
肿瘤(癌症)患者之家