Nuclear Medicine Department, University Hospital of Caen, Avenue de la Côte de Nacre, 14033, Caen, Cedex 9, France.
INSERM U1086 ANTICIPE, Normandy University, UNICAEN, Caen, France.
Mol Imaging Biol. 2022 Dec;24(6):1018-1027. doi: 10.1007/s11307-022-01753-x. Epub 2022 Jul 14.
Single-photon emission computed tomography has found an important place in preclinical cancer research. Nevertheless, the cameras dedicated to small animals are not widely available. The present study aimed to assess the feasibility of imaging small animals by a newly released 360° cadmium zinc telluride camera (VERITON, Spectrum Dynamics, Israel) dedicated to human patients.
A cylindrical phantom containing hot spheres was used to evaluate the intrinsic performance of the camera first without the presence of background activity and then with two contrasts between background and hot spheres (1/4 and 1/10). Acquisitions were repeated with different scan durations (10 and 20 min), two tested radioisotopes (Tc-99 m and I-123), and a set of reconstruction parameters (10 iterations [i] 8 subsets [s], 10i16s, 10i32s). A 3D-printed phantom mimicking a rat with four subcutaneous tumours was then used to test the camera under preclinical conditions.
The results obtained from the micro-hollow sphere phantom showed that it was possible to visualize spheres with an inner diameter of 3.95 mm without background activity. Moreover, spheres with diameters of 4.95 mm can be seen in the condition of high contrast between background and spheres (1/10) and 7.86 mm with lower contrast (1/4). The rat-sized phantom acquisitions showed that 10- and 8-mm subcutaneous tumours were visible with a good contrast obtained for the two radioisotopes tested in this study. Both Tc-99 m and I-123 measurements demonstrated that a 10-min acquisition reconstructed with an ordered subset expectation maximization algorithm applying 10i32s was optimal to obtain sufficient image quality in terms of noise, resolution, and contrast.
Phantom results showed the ability of the system to detect sub-centimetre lesions for various radioisotopes. It seemed feasible to image small animals using a 360° cadmium zinc telluride gamma camera for preclinical cancer research purposes.
单光子发射计算机断层扫描在临床前癌症研究中占有重要地位。然而，专门用于小动物的相机尚未广泛普及。本研究旨在评估一种新发布的 360° 碲化镉锌相机（以色列 Spectrum Dynamics 的 VERITON）用于小动物成像的可行性。
使用一个包含热球的圆柱形体模，首先在没有背景活动的情况下评估相机的固有性能，然后在背景和热球之间进行两次对比度测试（1/4 和 1/10）。使用不同的扫描时间（10 和 20 分钟）、两种测试放射性同位素（Tc-99m 和 I-123）和一组重建参数（10 次迭代 [i] 8 个子集 [s]、10i16s、10i32s）重复采集。然后，使用一个模拟带有四个皮下肿瘤的大鼠的 3D 打印体模在临床前条件下测试相机。
从微空心球体模获得的结果表明，在没有背景活动的情况下，可以可视化直径为 3.95mm 的球。此外，在背景与球之间对比度高（1/10）的情况下，可以看到直径为 4.95mm 的球，而在对比度较低（1/4）的情况下可以看到直径为 7.86mm 的球。大鼠大小的体模采集结果表明，对于两种在本研究中测试的放射性同位素，10 毫米和 8 毫米的皮下肿瘤是可见的，并且获得了良好的对比度。Tc-99m 和 I-123 测量结果表明，使用 10i32s 的有序子集期望最大化算法进行 10 分钟采集重建是获得足够图像质量（噪声、分辨率和对比度）的最佳选择。
体模结果表明该系统有能力检测各种放射性同位素的亚厘米级病变。对于临床前癌症研究目的，使用 360° 碲化镉锌伽马相机对小动物进行成像似乎是可行的。
