Radioactive seed localization procedures, using I seeds of typical activity 3.7 MBq and higher, are performed to localize nonpalpable lesions in the breast for surgical excision and pathology analysis. This study evaluated the use and dosimetry of I seeds of activity <3.7 MBq in radioactive seed localization procedures through retrospective health record review, Monte Carlo simulation, and experimental detection. An average seed strength at the time of specimen excision of 2.48 ± 0.629 MBq was used in 295 radioactive seed localization procedures at Gundersen Health System in La Crosse, Wisconsin, US. The average explanted seed activity served as a basis for Monte Carlo simulation of an I IsoAid Advantage seed embedded in soft tissue, which scored the dose deposited to soft tissue. Tabulated values of the dose to postsurgical residual tissue as a function of explanted tumor radius were shown and compared with previously published results. Use of seeds of activity from 1.44 to 3.7 MBq at the time of excision did not adversely affect seed detection and excision. The absorbed dose to residual tissue calculated using Monte Carlo was an average of 1.4 times larger than previously published results when scaled to identical seed strengths. This study demonstrates that seeds of activity <3.7 MBq can be used for radioactive seed localization procedures with no loss in efficacy and a benefit of reduced radiation dose to patients. This is important because the estimated radiation dose to residual tissue is approximately 1.4 times higher than previously indicated.

中文翻译：

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降低放射性的种子在乳房放射性种子定位中的应用。

使用典型活性为3.7 MBq或更高的I种子进行放射性种子定位程序，以定位乳房中不可触及的病变，以进行手术切除和病理分析。这项研究通过回顾性健康记录回顾，蒙特卡罗模拟和实验检测，评估了放射性种子定位程序中活性小于3.7 MBq的I种子的使用和剂量测定。在美国威斯康星州拉克罗斯市的Gundersen Health System进行的295项放射性种子定位程序中，样本切除时的平均种子强度为2.48±0.629 MBq。平均外植种子活性是蒙特卡洛模拟的嵌入在软组织中的IsoAid Advantage种子的基础，该种子对沉积到软组织的剂量进行了评分。显示了手术后残余组织剂量的列表值，该值是移植的肿瘤半径的函数，并与先前发表的结果进行了比较。切除时使用1.44至3.7 MBq的活性种子不会对种子的检测和切除产生不利影响。当按相同的种子强度定标时，使用蒙特卡洛方法计算的残留组织吸收剂量平均比以前发表的结果大1.4倍。这项研究表明，活性小于3.7 MBq的种子可用于放射性种子定位程序，而不会降低疗效，并且可减少对患者的辐射剂量。这很重要，因为对残留组织的估计辐射剂量比以前指示的大约高1.4倍。