Currently, hand-held gamma cameras are being developed for 99mTc imaging, mainly for sentinel lymph node detection. These cameras offer advantages, such as mobility and ease of access, and may be useful also for other applications such as biokinetic studies in animals or for imaging of small, superficial structures in patients. In this work, the suitability of a CZT-based hand-held camera for 177Lu imaging is investigated. The energy response of CZT-based detectors combined with the multiple photon emissions of 177Lu poses new challenges compared to 99mTc imaging, and a thorough camera characterisation is thus warranted. Three collimators (LEHR, LEHS, and MEGP) and three energy windows (55 keV, 113 keV, and 208 keV) are investigated. Characterised camera properties include the system spatial resolution, energy resolution, sensitivity, image uniformity, septal penetration, and temperature dependence. Characterisations are made starting from NEMA guidelines when applicable, with adjustments made when required. The applicability of the camera is demonstrated by imaging of a superficially located tumour in a patient undergoing [177 Lu]Lu-DOTA-TATE therapy. Overall, the results are encouraging. Compared to a conventional gamma camera, the hand-held camera generally has a higher sensitivity for a given collimator. For source-collimator distances below 3 cm, the spatial resolution FWHM is within 6 mm for the LEHR and MEGP collimators. Before uniformity correction, the central field-of-view integral uniformity shows best results for the 113-keV window, with values obtained between 11 and 14%. The corresponding values after uniformity correction are within 3%. Effects of septal penetration are observed but are manageable with a proper combination of collimator and energy window setting. Septal penetration and collimator scatter not only affect the 208-keV window but also contribute with counts in lower windows due to energy-tailing effects. The patient study revealed non-uniform uptake patterns in a region that appeared uniform in a conventional gamma camera image. The results show that the hand-held camera can be used for 177Lu imaging. A 113-keV energy window combined with LEHR or MEGP collimators provides the best image system characteristics.

中文翻译：

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用于177Lu成像的基于CZT的手持式伽马相机的特性。

目前，手持式伽马相机正在开发用于99mTc成像，主要用于前哨淋巴结检测。这些相机具有诸如移动性和易于接近等优点，并且对于其他应用（例如动物的生物动力学研究）或患者的微小表层结构的成像也可能有用。在这项工作中，研究了基于CZT的手持相机对177Lu成像的适用性。与99mTc成像相比，基于CZT的探测器的能量响应与177Lu的多光子发射相结合提出了新的挑战，因此必须对照相机进行全面的表征。研究了三个准直仪（LEHR，LEHS和MEGP）和三个能量窗（55 keV，113 keV和208 keV）。相机的特征包括系统空间分辨率，能量分辨率，灵敏度，图像均匀性，隔片渗透和温度依赖性。从适用的NEMA指南开始进行表征，并在需要时进行调整。摄像机的适用性通过对正在接受[177 Lu] Lu-DOTA-TATE治疗的患者中位于表面的肿瘤进行成像来证明。总体而言，结果令人鼓舞。与传统的伽玛相机相比，手持式相机对于给定的准直器通常具有更高的灵敏度。对于低于3 cm的源准直仪距离，LEHR和MEGP准直仪的空间分辨率FWHM在6 mm之内。在进行均匀度校正之前，中心视场的整体均匀度显示113keV窗口的最佳结果，其值在11％至14％之间。均匀度校正后的相应值在3％以内。可以观察到间隔穿透的效果，但通过将准直仪和能量窗口设置适当组合可以解决。隔片的穿透和准直器散射不仅影响208keV窗口，而且由于能量拖尾效应，还会影响较低窗口中的计数。病人研究发现在常规伽马相机图像中出现均匀区域的摄取模式不均匀。结果表明，该手持摄像机可用于177Lu成像。113-keV能量窗口与LEHR或MEGP准直仪结合使用，可提供最佳的图像系统特性。病人研究显示，在常规伽马相机图像中出现均匀区域的摄取模式不均匀。结果表明，该手持摄像机可用于177Lu成像。113-keV能量窗口与LEHR或MEGP准直仪结合使用可提供最佳的图像系统特性。病人研究显示，在常规伽马相机图像中出现均匀区域的摄取模式不均匀。结果表明，该手持摄像机可用于177Lu成像。113-keV能量窗口与LEHR或MEGP准直仪结合使用可提供最佳的图像系统特性。