Pouw Bas, de Wit-van der Veen Linda J, van der Hage Jos A, Vrancken Peeters Marie-Jeanne T F D, Wesseling Jelle, Stokkel Marcel P M, Valdés Olmos Renato A
Departments of aNuclear Medicine bSurgical Oncology cPathology, The Netherlands Cancer Institute, Antoni Van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
Nucl Med Commun. 2014 Sep;35(9):961-6. doi: 10.1097/MNM.0000000000000159.
Radioactive seed localization (RSL) uses an iodine-125 ((125)I) seed as a marker for tumour location. The (125)I seed is implanted into the tumour and enables intraoperative localization with a conventional gamma probe. However, specimen margins in relation to the (125)I seed are estimated on the basis of gamma-probe readings only. A novel device, freehand SPECT, is capable of measuring the distance from the resection plane to the (125)I seed. The aim of this feasibility study was to establish the accuracy of this device in predicting resection margins in ex-vivo tumour specimens excised with RSL guidance.
In this feasibility study 10 patients with nonpalpable breast cancer scheduled for wide local excision with RSL were included. After surgery, the specimens containing the breast tumour and the (125)I seed were scanned using freehand SPECT. Measurements from five directions were taken and compared with distances measured by means of an ex-vivo computed tomographic (CT) scan and related to the pathology report.
The difference between freehand SPECT and CT measurements was 2.9±2.7 mm (mean±SD). One patient had a positive margin based on freehand SPECT. This specimen contained a focal irradical resection ventral of the tumour based on the pathology report. The smallest distance to the (125)I seed was 4 mm for the freehand SPECT and 5 mm for the CT scan.
Accurate ex-vivo measurements of the tumour resection margins using (125)I seeds and freehand SPECT are feasible in patients undergoing breast-conserving surgery. Incorporation of the freehand-SPECT device in RSL protocols may enable a real-time estimation of resection margins, which may be useful for surgeons to adjust resection planes.
放射性种子定位（RSL）使用碘-125（¹²⁵I）种子作为肿瘤定位的标记物。¹²⁵I种子被植入肿瘤内，并可通过传统的γ探针进行术中定位。然而，仅基于γ探针读数来估计标本边缘与¹²⁵I种子的关系。一种新型设备，即徒手单光子发射计算机断层扫描（SPECT），能够测量从切除平面到¹²⁵I种子的距离。本可行性研究的目的是确定该设备在预测RSL引导下切除的离体肿瘤标本切缘方面的准确性。
在本可行性研究中，纳入了10例计划接受RSL引导下广泛局部切除的不可触及性乳腺癌患者。手术后，使用徒手SPECT对包含乳腺肿瘤和¹²⁵I种子的标本进行扫描。从五个方向进行测量，并与通过离体计算机断层扫描（CT）扫描测量的距离进行比较，并与病理报告相关联。
徒手SPECT与CT测量之间的差异为2.9±2.7毫米（平均值±标准差）。一名患者基于徒手SPECT切缘阳性。根据病理报告，该标本在肿瘤腹侧包含一个局灶性根治性切除。徒手SPECT到¹²⁵I种子的最小距离为4毫米，CT扫描为5毫米。
对于接受保乳手术的患者，使用¹²⁵I种子和徒手SPECT对肿瘤切除边缘进行准确的离体测量是可行的。将徒手SPECT设备纳入RSL方案可能有助于实时估计切除边缘，这可能有助于外科医生调整切除平面。
