Is the “Ideal” γ-Probe for Intraoperative Radioguided Surgery Conceivable?
Is the “Ideal” γ-Probe for Intraoperative Radioguided Surgery Conceivable?
复制标题
用于术中放射引导手术的“理想”γ 探针是否可以想象？
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
D. Rubello
中科院分区：
文献类型：
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作者：
G. Mariani;A. Vaiano;O. Nibale;D. Rubello
在本期《核医学杂志》上发表的Classe等人的文章（第395-399（1）页）提供了一个机会，可以从推测和实践的角度考虑使用术中探头进行放射导向手术。在20世纪80年代引入放射免疫引导手术后，在过去的10年左右，术中探针的全球使用持续呈指数增长。这些探针现在用于各种放射导向外科手术，主要（但不限于）处理恶性疾病的治疗，例如寻找前哨淋巴结（2- 13）。这种趋势促使制造商开发并向市场推出几种不同类型的探针，每种探针都声称是广泛临床常规和实验性临床方案中遇到的技术困难的最终、独特的解决方案。考虑到放射导向手术的目标是通过皮肤的手术切口搜索（计数）、检测和定位热病变，可以定义核医学医生和外科医生在选择术中探头时应考虑的特征（10）。因此，术中探针首先应该是小的并且易于操作，从而允许在适当的时候进行微创手术。当考虑特定应用时，探针的人体工程学方面也是重要的;例如，将检测部件设计在侧窗上而不是在探针的尖端上对于腹腔镜检查或胸腔镜检查期间的放射引导手术的应用可能是有利的。敏感性对于检测热病变是重要的。它可以被定义为探头可以检测到的发射辐射的分数;整体灵敏度与几何分量（与探测器相交的发射辐射的分数，这取决于探头对向的立体角）和固有分量（探测器内吸收的辐射的分数，这取决于探测材料）有关。高灵敏度允许检测低活性源。空间分辨率和屏蔽是定位放射源的关键参数;良好的空间分辨率允许人们区分彼此靠近的放射源，如当前哨淋巴结靠近放射性胶体注射部位时。术中探头预期用于定向计数。在这方面，屏蔽对于防止来自不需要位置的辐射与检测器相互作用并产生计数是重要的;当存在高背景信号时，该参数主要是关键的。能量分辨率是计数性能的重要决定因素，因为良好的能量分辨率允许基于能量辨别来识别和丢弃散射辐射。散射辐射导致空间信息的模糊，并虚假地增加背景;因此，重要的是丢弃来自辐射的散射分量的计数。能量和计数率的线性也是期望的，以确保探针在临床实践中使用的放射性核素和活性的范围内最佳地操作。表1总结了定义术中穿刺针性能的最重要物理参数。显然，对于临床使用的所有放射性核素来说，具有最高灵敏度、最佳能量分辨率（表示为光峰的百分比FWHM）、最佳散射抑制和最低空间分辨率的探针将是首选探针。不幸的是，没有一个探头可以为这些性能参数中的每一个具有最佳值;例如，灵敏度和空间分辨率彼此成反比。这些参数的复杂性和其中一些参数之间可能的冲突清楚地表明，无论是从理论上还是从实践的角度来看，都不可能设想出在所有参数中具有最佳性能的探针。因此，可以合理地假设最佳探测器通常是最佳折衷方案.在这种观点中，应该强调的是，最佳的折衷方案严格取决于计划的放射导向手术的类型。例如，当探针的主要用途是对乳腺癌或黑色素瘤（或其他具有高淋巴转移潜力的实体瘤）患者的前哨淋巴结进行放射导向活检时，最重要的参数是灵敏度。事实上，它是至关重要的，以检测与探针，也，淋巴结计数率低（10，11）。另一方面，最大空间分辨率虽然是理想的，但相对于前哨淋巴结手术的灵敏度而言，其重要性较小，尤其是在包括完全切除所有热前哨淋巴结的手术方案中。类似地，旨在限制探头角度视野的探头准直可能不是前哨淋巴结活检的关键因素，至少在2004年11月3日接收; 2004年12月8日接受修订时是如此。如需通信或重印，请联系：Giuliano马里亚尼，MD，Regional Center of Nuclear Medicine，University of比萨医学院，Via Roma 67，I-56126比萨，意大利。电子邮件：g.马里亚尼@ med.unipi.it
Publication in this issue of The Journal of Nuclear Medicine of the article by Classe et al. (pages 395–399 (1)) gives the opportunity for some considerations both from a speculative and from a practical point of view about the use of intraoperative -probes for radioguided surgery. After a slow start with the introduction of radioimmunoguided surgery in the 1980s, the last 10 years or so have witnessed a continuous exponential growth in the worldwide use of intraoperative -probes. These probes are now used in a variety of radioguided surgical procedures, mostly (but not exclusively) dealing with treatment of malignant disease, such as in the search for sentinel lymph nodes (2– 13). This trend has driven manufacturers to develop and introduce to the market several different types of -probes, each claimed to be the ultimate, unique solution to the technical difficulties encountered both in wide clinical routine and in experimental clinical protocols. The features that the nuclear medicine physician and the surgeon should take into account when choosing an intraoperative -probe can be defined, considering that the goal of radioguided surgery is to search for (count), detect, and localize hot lesions through a surgical incision of the skin (10). Therefore, an intraoperative probe should first be small and easy to handle, thus allowing minimally invasive surgery whenever adequate. The ergonomic aspects of -probes are important also when specific applications are contemplated; for instance, designing the detecting component on a lateral window rather than on the tip of the probe could be advantageous for applications of radioguided surgery during laparoscopy or thoracoscopy. Sensitivity is important for detecting hot lesions. It can be defined as the fraction of the emitted radiation that the probe can detect; overall sensitivity is linked to a geometric component (fraction of emitted radiation that intersects the detector, which depends on the solid angle subtended by the probe) and to an intrinsic component (fraction of radiation absorbed within the detector, which depends on the detecting material). High sensitivity allows the detection of low-activity sources. Spatial resolution and shielding are the key parameters for localizing the source; good spatial resolution allows one to distinguish sources close to each other, as when the sentinel lymph node is close to the radiocolloid injection site. Intraoperative probes are intended for directional counting. In this regard, shielding is important to prevent radiation from unwanted locations from interacting with the detector and producing counts; this parameter is critical mostly when a high background signal is present. The energy resolution is an important determinant in counting performance, since good energy resolution allows one to recognize and discard scattered radiation based on energy discrimination. Scattered radiation contributes to the blurring of spatial information and spuriously increases background; therefore, it is important to discard counts coming from the scattered component of radiation. Linearity in energy and counting rate are also desirable to ensure that probes operate optimally in the range of radionuclides and activities used in clinical practice. The most important physical parameters defining the performance of an intraoperative -probe are summarized in Table 1. Obviously, a probe having the highest sensitivity, the best energy resolution (expressed as the percentage FWHM of the photopeak), the best scatter rejection, and the lowest spatial resolution for all radionuclides used clinically would be the probe of choice. Unfortunately, no single probe can have optimal values for each of these performance parameters; for instance, sensitivity and spatial resolution are inversely related to each other. The complexity of these parameters and possible conflict between some of them clearly indicate that it is not possible, either from a theoretic or from a practical point of view, to conceive a -probe characterized by the best performance in all parameters. Therefore, it is reasonable to assume that the best -probe is generally the best compromise. In this view, it should be emphasized that the best compromise depends strictly on the type of radioguided surgery that is planned. For example, when the predominant use of the -probe is for radioguided biopsy of the sentinel lymph node in patients with breast cancer or with melanoma (or with other solid tumors characterized by a high lymphogenic metastatic potential), the most important parameter is sensitivity. In fact, it is crucial to detect with the -probe, also, lymph nodes with a low counting rate (10,11). On the other hand, maximum spatial resolution, although desirable, is relatively less important than sensitivity for sentinel lymph node procedures, especially in surgical protocols including complete removal of all hot sentinel nodes. Similarly, probe collimation aimed at restricting the angular field of view of the probe may not be a crucial factor in sentinel lymph node biopsy, at least when the Received Nov. 3, 2004; revision accepted Dec. 8, 2004. For correspondence or reprints contact: Giuliano Mariani, MD, Regional Center of Nuclear Medicine, University of Pisa Medical School, Via Roma 67, I-56126 Pisa, Italy. E-mail: g.mariani@med.unipi.it
NaI(T1)、CdTe 和 HgI2 手术探头的比较：散射补偿对探头性能的影响。
影响因子：
3.8
作者：
Kwo,DP;Barber,HB;Barrett,HH;Hickernell,TS;Woolfenden,JM
通讯作者：
Woolfenden,JM