Ho Ching-Chun, Chen Yu-Hung, Liu Shu-Hsin, Chen Hwa-Tsung, Lee Ming-Che
Department of Surgery, Buddhist Tzu Chi General Hospital and Tzu Chi University, Hualien, Taiwan.
Department of Nuclear Medicine, Buddhist Tzu Chi General Hospital and Tzu Chi University, Hualien, Taiwan.
Tzu Chi Med J. 2019 Jul-Sep;31(3):163-168. doi: 10.4103/tcmj.tcmj_88_18.
Sentinel lymph node (SLN) sampling has become a standard practice in managing early-stage breast cancer. Lymphoscintigraphy is one of the major methods used. The radioactive tracer used in Taiwan is Tc-99m phytate. However, this agent is not commonly used around the world and the optimal imaging time has not been studied. Thus, we investigated the optimal imaging time of Tc-99m phytate lymphoscintigraphy for SLN mapping in patients with breast cancer.
We retrospectively reviewed SLN Tc-99m phytate lymphoscintigraphies in 135 patients with breast cancer between August 2013 and November 2017. The time for the first SLN to be visualized after radiotracer injection was recorded to determine the optimal imaging time. If no SLN was identified on imaging, the scan was continued to 60 min. We also recorded the presurgical technical and clinical factors to analyze the risk factors for nonvisualization of SLN. Each patient's postoperative axillary lymph node status was also recorded.
Axillary SLNs were identified on imaging in 94.8% of the patients. All first SLNs presented within 30 min. In 6 of 7 patients with negative imaging, SLNs were identified during surgery using either blue dye or a hand-held gamma probe. Nonvisualization of SLNs on lymphoscintigraphy was significantly associated with a lower injection dose (1.0 mCi vs. 2.0 mCi), 4-injection protocol (compared to 2-injection), and injection around an outer upper quadrant tumor. In addition, patients with axillary lymph node metastasis had a higher percentage of SLN image mapping failure, with a marginally significant difference.
Based on our study, 30 min after Tc-99m phytate injection is the optimal time for lymphoscintigraphy and delayed imaging beyond 30 min is not necessary. In addition, a lower injection dose, the 4-injection method, and an injection near the outer upper quadrant tumor should be avoided to minimize nonvisualization of SLNs.
前哨淋巴结（SLN）活检已成为早期乳腺癌治疗的标准做法。淋巴闪烁造影术是主要使用的方法之一。台湾使用的放射性示踪剂是锝-99m植酸盐。然而，这种试剂在世界范围内并不常用，且最佳成像时间尚未得到研究。因此，我们研究了锝-99m植酸盐淋巴闪烁造影术在乳腺癌患者SLN定位中的最佳成像时间。
我们回顾性分析了2013年8月至2017年11月期间135例乳腺癌患者的SLN锝-99m植酸盐淋巴闪烁造影术。记录放射性示踪剂注射后首次观察到SLN的时间，以确定最佳成像时间。如果在成像中未发现SLN，则将扫描持续至60分钟。我们还记录了术前技术和临床因素，以分析SLN未显影的危险因素。还记录了每位患者术后腋窝淋巴结状态。
94.8%的患者在成像中发现腋窝SLN。所有首次发现的SLN均在30分钟内出现。在7例成像阴性的患者中，有6例在手术中使用蓝色染料或手持γ探测器发现了SLN。淋巴闪烁造影术中SLN未显影与较低的注射剂量（1.0毫居里对2.0毫居里）、4次注射方案（与2次注射相比）以及在外上象限肿瘤周围注射显著相关。此外，腋窝淋巴结转移患者的SLN图像定位失败率较高，差异有统计学意义。
根据我们的研究，锝-99m植酸盐注射后30分钟是淋巴闪烁造影术的最佳时间，无需在30分钟后进行延迟成像。此外，应避免较低的注射剂量、4次注射方法以及在外上象限肿瘤附近注射，以尽量减少SLN未显影的情况。
